JAXA Supercomputer System Annual Report April 2017-March 2018

Basic research for system integration of silent supersonic airplane technologies
Report Number：R17ETET01
Subject Category：Skills Acquisition System
URL：https://www.jss.jaxa.jp/ar/e2017/4466/
Responsible Representative
Yoshikazu Makino,
Next Generation Aeronautical Innovation Hub Center, Aeronautical Technology Directorate

Contact Information
Yoshikazu Makino makino@chofu.jaxa.jp

Members
Yuki Kishi, Shinya Kitazaki, Jun Yamamoto, Go Iwamoto, Masahiro Kanazaki,
Hiroaki Fujiwara, Hideyuki Obata, Yohei Kasuga, Masaya Miyazaki, Yuki Sato

Abstract
The system integration design technologies for achieving low sonic-boom, low aerodynamic drag, lowlanding and take-off noise, and light weight simultaneously are the key technologies for future supersonic
airplanes. JAXA is promoting the R&D for these technologies based on our experiences of demonstrating
the advanced low-drag and low-boom design concepts.
http://www.aero.jaxa.jp/eng/research/frontier/sst/

Reasons for using of JSS2
To achieve low sonic-boom, low aerodynamic drag, low landing and take-off noise, and light weight
simultaneously, the multi-objective optimization tools are utilized in the design study. The supercomputer is necessary to obtain the multiple objective function efficiently with many numericalsimulations.

Achievements of the Year
The planform dependency for supersonic airfoil was investigated. In results, it was found that, in airfoil
design, the shape of the forward camber and the twisted angle have the largest influence on dragreduction.

JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.1 Surface pressure distribution on high and low swept back wing.

Publications
 Peer-reviewed papers
1) Y. Kishi, M. Kanazaki, Y. Makino and K. Matsushima, Wing planform dependency on optimum
supersonic airfoil, Transactions of the JSME (in Japanese), Vol.83, (2017), p.16-00454.
 Non peer-reviewed papers
1) Y. Kishi, S. Kitazaki, A. Ariyarit, Y. Makino and M. Kanazaki, Planform Dependency of Optimum
Supersonic Airfoil for Wing-Body-Nacelle Configuration using Multi-Fidelity Design Optimization,
AIAA 2017-4468, (2017).
 Presentations
1) Y. Kishi, M. Kanazaki and Y. Makino, Investigation of supersonic forward-swept wing for
simultaneous reduction of sonic boom and aerodynamic drag, 49th Fluid Dynamics
Conference/35th Aerospace Numerical Simulation Symposium, 1A09, (2017).
2) J. Akatsuka, N. Ogura, T. Homma, Y. Watanabe and M. Kameda, Experimental Evaluation of
Acoustic and Thrust Characteristics, 49th Fluid Dynamics Conference/35th Aerospace Numerical
Simulation Symposium, 1B11, (2017).
3) Y. Kishi, M. Kanazaki and Y. Makino, Study on SST with Forward Swept Wing for Simultaneous
Reduction of Low Drag and Low Boom, 55th Aircraft symposium, 3A02, (2017).
4) G. Iwamoto, Y. Kasuga, H. Ishikawa and N. Tokugawa, An Approach to Fully Natural Laminar Flow
Wing Design of NEXST-1, 55th Aircraft symposium, 3A08, (2017).

JAXA Supercomputer System Annual Report April 2017-March 2018

Usage of JSS2
 Computational Information
Parallelization Methods

MPI

Thread Parallelization Methods

Automatic Parallelizatio

Number of Processes

4 - 128

Elapsed Time per Case

12,000.00 seconds

 Resources Used
Fraction of Usage in Total Resources*1 (%): 0.35
Details
Computing Resources
System Name

Amount of Core Time (core x hours)

Fraction of Usage*2 (%)

SORA-MA

1,789,166.76

0.24

SORA-PP

83,621.32

1.05

SORA-LM

1,104.56

0.57

SORA-TPP

0.00

0.00

File System Resources
File System Name

Storage assigned(GiB)

Fraction of Usage*2 (%)/home

2,969.57

2.06

/data

73,850.95

1.37

/ltmp

16,927.09

1.28

Archiver Resources
Archiver System Name

Storage used(TiB)

Fraction of Usage*2 (%)

J-SPACE

75.21

3.23

*1 Fraction of Usage in Total Resources: Weighted average of three resource types (computing, file system,
and archiver)*2 Fraction of Usage: Percentage of usage relative to each resource used in one year

JAXA Supercomputer System Annual Report April 2017-March 2018

Numerical calculation of Green engine (study of ultrahigh-temperature low NOx emission
combustor technology) filming-type airblast atomizing process
Report Number：R17ETET03
Subject Category：Skills Acquisition System
URL：https://www.jss.jaxa.jp/ar/e2017/4467/
Responsible Representative
Toshiya Nakamura,
Aeronautical Technology Directorate, Next Generation Aeronautical Innovation Hub Center

Contact Information
Kazuaki Matsuura matsuura.kazuaki@jaxa.jp

Members
Kazuaki Matsuura, Mitsumasa Makida, Naoki Nakamura, Jun Iino, Huilai Zhang,
Shunya Uesaka, Tomoyuki Iwasaki, Ryuta Shinohara, Kazuki Toukaishi

Abstract
Experimental study of planner filming-type airblast atomizer shows the clear effects of the ambientpressure and the vane angles on atomization characteristics. Since the atomization process occurs in the
narrow region which is vicinity of the injection outlet, it is difficult to understand the atomization
phenomena only by experiment. The objective of this work is to understand the atomization mechanism
by numerical study which calculate the atomization field in the near region of the injection outlet.

Reasons for using of JSS2
The particle diameter is order of 10 micron in the experiment. In order to calculate this size ofatomization field precisely, large scale calculation with more than a few of hundred million of cells which
size is a few micron meter order is needed and the use of super computer is necessary.

Achievements of the Year
We revised VOF code to reproduce the experimental results of planner filming-type airblast atomizer
that the particle diameter with lower ambient pressure becomes larger. We conducted the numericalsimulation of milk crown as benchmark test (Fig.1,2). It was confirmed that the revised code reproduce
instability needed to form a crown. In the numerical analysis by the revised code for planner filming-typeairblast atomizer (Fig.3,4), it was shown that large droplets are divided from ligament, and we came to
be able to understand detailed mechanism of break-up which is difficult in the experiment.

JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.1 Milk crown (Old code)

Fig.2 Milk crown (New code)

JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.3 Planner filming-type airblast atomizer (Low ambient pressure)Fig.4 Planner filming-type airblast atomizer (High ambient pressure)JAXA Supercomputer System Annual Report April 2017-March 2018

Publications
N/A

Usage of JSS2
 Computational Information
Parallelization Methods

MPI

Thread Parallelization Methods

OpenMP

Number of Processes

96 - 768

Elapsed Time per Case

600.00 hours

 Resources Used
Fraction of Usage in Total Resources*1 (%): 0.53
Details
Computing Resources
System Name

Amount of Core Time (core x hours)

Fraction of Usage*2 (%)

SORA-MA

4,123,371.56

0.55

SORA-PP

1,243.18

0.02

SORA-LM

0.00

0.00

SORA-TPP

0.00

0.00

File System Resources
File System Name

Storage assigned(GiB)

Fraction of Usage*2 (%)/home

168.11

0.12

/data

42,757.27

0.79

/ltmp

14,865.46

1.12

Archiver Resources
Archiver System Name

Storage used(TiB)

Fraction of Usage*2 (%)

J-SPACE

0.14

0.01

*1 Fraction of Usage in Total Resources: Weighted average of three resource types (computing, file system,
and archiver)*2 Fraction of Usage: Percentage of usage relative to each resource used in one year

JAXA Supercomputer System Annual Report April 2017-March 2018

Research on combustor simulation
Report Number：R17ETET05
Subject Category：Skills Acquisition System
URL：https://www.jss.jaxa.jp/ar/e2017/4468/
Responsible Representative
Takashi Aoyama, Aeronautical Technology Directorate, Numerical Simulation Research Unit

Contact Information
Himeko Yamamoto himeko@toki.waseda.jp

Members
Himeko Yamamoto

Abstract
For the development of a jet engine combustor with high environmental compatibility, we develop the
combustion calculation code that can capture the pressure propagation and chemical reaction withpractical calculation cost. In addition, a verification calculation of this calculation code is conducted on
the scramjet test engine of DLR.

Reasons for using of JSS2
It is necessary to use supercomputer to conduct development and verification of the combustion
calculation code.

Achievements of the YearIn this research, the implementation of the combustion calculation code based on compressible flamelet
model to a density-based fluid analysis solver, FaSTAR (FAST Aerodynamic Routines) was conducted.
Then, an artificial neural network (ANN) model was applied to reduce the calculation cost whenreferring to the flamelet library. The ANN model has 2 input units (mixture fraction and scalardissipation rate), 3 hidden units, and output units corresponding to mass fraction of each chemical
species (As an example, Fig.1 shows the ANN model of OH mass fraction). Approximation of theflamelet library using this model achieved reduction of memory usage (more than 50%) during numericalsimulation compared with conventional linear interpolation. For evaluation of this combustion
calculation code in actual combustion field, a numerical simulation of the hydrogen combustion in ascramjet test engine of the German Aerospace Center (DLR) was conducted (Fig.2 shows time-averaged
density distribution by ANN model).

JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.1 OH mass fraction generated by ANN

Fig.2 Time-averaged density distribution [kg/m3]

Publications
 Non peer-reviewed papers
1) Himeko Yamamoto, Rui Toyonaga, Yasuhiro Mizobuchi, Tetsuya Sato, Numerical analysis of jet
lifted flames using G-equation, JAXA Special Publication, 2017.12
2) Rui Toyonaga, Himeko Yamamoto, Yasuhiro Mizobuchi, Tetsuya Sato, Numerical investigation onsupersonic combustion in SCRAMJET engine by FaSTAR, JAXA Special Publication, 2017.12
 Presentations
1) Himeko Yamamoto, Rui Toyonaga, Yasuhiro Mizobuchi, Tetsuya Sato, Numerical study on flame
structure of jet lifted flames by FaSTAR, 57th Aerospace Propulsion Conference of Japan Society
for Aeronautical and Space Science, 2017.3
2) Himeko Yamamoto, Rui Toyonaga, Yasuhiro Mizobuchi, Tetsuya Sato, Numerical analysis of jet
lifted flames using G-equation, 49th Fluid Dynamics Conference/ 35th Aerospace Numerical
Simulation Symposium, 2017.6
3) Himeko Yamamoto, Rui Toyonaga, Yusuke Komatsu, Koki Kabayama, Yasuhiro Mizobuchi, Tetsuya
Sato, Improvement of compressible flamelet model using artificial neural network, The Asian Joint
Conference on Propulsion and Power, 2018.3

JAXA Supercomputer System Annual Report April 2017-March 2018

Usage of JSS2
 Computational Information
Parallelization Methods

MPI

Thread Parallelization Methods

N/A

Number of Processes

2 - 1024

Elapsed Time per Case

120.00 hours

 Resources Used
Fraction of Usage in Total Resources*1 (%): 0.60
Details
Computing Resources
System Name

Amount of Core Time (core x hours)

Fraction of Usage*2 (%)

SORA-MA

4,907,710.77

0.65

SORA-PP

4,541.23

0.06

SORA-LM

1.66

0.00

SORA-TPP

0.00

0.00

File System Resources
File System Name

Storage assigned(GiB)

Fraction of Usage*2 (%)/home

476.84

0.33

/data

19,531.26

0.36

/ltmp

1,953.13

0.15

Archiver Resources
Archiver System Name

Storage used(TiB)

Fraction of Usage*2 (%)

J-SPACE

0.48

0.02

*1 Fraction of Usage in Total Resources: Weighted average of three resource types (computing, file system,
and archiver)*2 Fraction of Usage: Percentage of usage relative to each resource used in one year

JAXA Supercomputer System Annual Report April 2017-March 2018

CFD analysis of wind turbine wake
Report Number：R17ETET09
Subject Category：Skills Acquisition System
URL：https://www.jss.jaxa.jp/ar/e2017/4469/
Responsible Representative
Yasutada Tanabe, Aeronautical Technology Directorate, Next Generation Aeronautical Innovation
Hub Center

Contact Information
Keita Kimura k.kimura@ilab.eco.rcast.u-tokyo.ac.jp

Members
Keita Kimura, Yasutada Tanabe, Yousuke Shinozaki

Abstract
In a large wind farm (arrays of wind turbines), wind turbine wake can cause power deficits or/and
additional fatigue in turbine stands in wake region. In this study, several wake simulations were
performed to obtain the characteristics of wind profiles in wind turbine wakes. These information canbe used for design of wind farm. In this year, we focused on the effect of the properties of natural wind,such as wind shear and wind fluctuation.

Reasons for using of JSS2
In order to resolve the detail structure of wind turbine wake, computational domain should extends toabout 10 rotor diameters downwind. On the other hand, to resolve the fluctuations from rotational
blades, grid scales need to be the order of chord length of blade tips. As a result, it is necessary to put
large computational grid which has high grid resolution. Thanks to JSS2, such simulations of highcomputational cost can be performed.

Achievements of the YearIn this year, two inflow conditions were generated to model the characteristics of natural wind. One ofthem is the atmospheric boundary layer (ABL) conditon whose inflow speed varies with height above
ground (wind shear), and the other is atmospheric turbulence condition whose inflow has specified
fluctuations. By using such conditions, we investigated effects of natural wind on the wind speeds inwake regions. As the results of the velocity deficit in wake region, the effect of wind shear is not strong
in far-wake region. On the other hand, the atmospheric turbulence condition accelerates the recovery ofwind speed by causing dynamic mixing of tip vortices.

JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.1 wake simulation by using ABL condition

Fig.2 Contour of wind speeds ( upper : uniform condition lower: ABL condition)

JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.3 Isosurface of vorticity ( upper : turbulence condition lower : uniform condition)

Fig.4 Transition of averaged wind speed in wake region

Publications
 Peer-reviewed papers
1) Keita Kimura, Yasutada Tanabe, Takashi Aoyama, Yuichi Matsuo, Chuichi Arakawa, and Makoto
Iida, "CFD simulations of a wind turbine for analysis of tip vortex breakdown," Journal of Physics:
Conference Series, 749 (2016) 012013, 2016

JAXA Supercomputer System Annual Report April 2017-March 2018

 Non peer-reviewed papers
1) Yosuke Shinozaki, Yasutada Tanabe, Takashi Aoyama, Yuichi Matsuo, Chuichi Arakawa, Hirofumi
Daiguji, and Makoto Iida, "A Study on Spreading Wakes by Wind Turbine Wake Simulation,"
Nagare, 36(6), pp.403-408, 2017.
 Presentations
1) Yosuke Shinozaki, Yasutada Tanabe, Takashi Aoyama, Yuichi Matsuo, Chuichi Arakawa, and
Makoto Iida, "Effect of tip vortex release cycle on wind turbine wake", 49th Fluid Dynamics
Conference/35th Aerospace Numerical Simulation Symposium, Tokyo, 2017.
2) Yosuke Shinozaki, Yasutada Tanabe, Takashi Aoyama, Yuichi Matsuo, Chuichi Arakawa, Hirofumi
Daiguji, Makoto Iida, "A Study on Spreading Wakes by Wind Turbine Wake Simulation", Annual
meeting of Japan Society of Fluid Mechanics2017, Tokyo, pp.1-6, 2017.
3) Yousuke Shinozaki, Yasutada Tanabe, Takashi Aoyama, Yuichi Matsuo, Chuichi Arakawa, and
Makoto Iida, "Dependent characteristic of tip vortex release cycle on energy recovery in windturbine wake", The Japan Society of Mechanical Engineers annual meeting, 17(1), Saitama,
J0540206, 2017.
4) Yosuke Shinozaki, Yasutada Tanabe, Takashi Aoyama, Yuichi Matsuo, Chuichi Arakawa, Hirofumi
Daiguji, Makoto Iida, "Dependent characteristics of tip vortices on kinetic energy transition in windturbine wakes", WindEurope Conference & Exhibition 2017, Amsterdam, PO153, 2017.
5) Keita Kimura, Yasutada Tanabe, Takashi Aoyama, Yuichi Matsuo, Chuichi Arakawa, and Makoto
Iida, "Evaluation of wind turbine wake simulation focusing on grid resolution", WWEC 2016, Tokyo,
Japan, October, 2016.
6) Keita Kimura, Yasutada Tanabe, Takashi Aoyama, Yuichi Matsuo, Chuichi Arakawa, and Makoto
Iida, "CFD analysis of the effect of Atmospheric Boundary Layer on wind turbine wake", AHS 73rd
Forum, #28, Texas, USA, May, 2017.
7) Keita Kimura, Yasutada Tanabe, Takashi Aoyama, Yuichi Matsuo, Chuichi Arakawa, and Makoto
Iida,"Dependency of tip speed ratio for tip vortex decay around wind turbine blade", 49th Fluid
Dynamics Conference/35th Aerospace Numerical Simulation Symposium, 1B08, Tokyo,2017.
8) Keita Kimura, Yasutada Tanabe, Takashi Aoyama, Yuichi Matsuo, Chuichi Arakawa, and Makoto
Iida, "Numerical study of wake flow mixing in turbulence condition", WindEUROPE
Conference&Exhibition2017, Amsterdam, Netherlands, November, 2017.
9) Keita Kimura, Yasutada Tanabe, Takashi Aoyama, Yuichi Matsuo,and Makoto Iida, "Numericalanalysis of wind distributions in wind turbine wake", 39th Japan Wind Energy Symposium, Tokyo,
2017.

JAXA Supercomputer System Annual Report April 2017-March 2018

Usage of JSS2
 Computational Information
Parallelization Methods

MPI

Thread Parallelization Methods

OpenMP

Number of Processes

2-8

Elapsed Time per Case

1,000.00 hours

 Resources Used
Fraction of Usage in Total Resources*1 (%): 0.75
Details
Computing Resources
System Name

Amount of Core Time (core x hours)

Fraction of Usage*2 (%)

SORA-MA

561,986.58

0.08

SORA-PP

1,028,549.46

12.88

SORA-LM

0.09

0.00

SORA-TPP

0.00

0.00

File System Resources
File System Name

Storage assigned(GiB)

Fraction of Usage*2 (%)/home

096.56

0.07

/data

10,986.33

0.20

/ltmp

2,197.27

0.17

Archiver Resources
Archiver System Name

Storage used(TiB)

Fraction of Usage*2 (%)

J-SPACE

0.00

0.00

*1 Fraction of Usage in Total Resources: Weighted average of three resource types (computing, file system,
and archiver)*2 Fraction of Usage: Percentage of usage relative to each resource used in one year

JAXA Supercomputer System Annual Report April 2017-March 2018

Numerical Study of Hypersonic Intake
Report Number：R17ETET10
Subject Category：Skills Acquisition System
URL：https://www.jss.jaxa.jp/ar/e2017/4470/
Responsible Representative
Takashi Aoyama, Aeronautical Technology Directorate, Numerical Simulation Research Unit

Contact Information
Atsushi Hashimoto hashimoto.atsushi@jaxa.jp

Members
Tsukasa Nagao, Hidekazu Yoshida, Masakazu Sano

Abstract
JAXA is developing a hypersonic turbojet which work at less than Mach 1 to Mach 5. The intake of thehypersonic turbojet reduces air speed and compresses air. We conducted the CFD analysis to understandthese flow field and operating conditions and develop a higher efficiency hypersonic turbojet.
http://www.aero.jaxa.jp/eng/research/frontier/hst/

Reasons for using of JSS2
We need to calculate about 30 unsteady or steady three dimensional models to investigate theperformance of the inlet for High Mach Integrated Control experiment.

We use fast flow solver

FaSTAR developed by JAXA for the CFD analysis.

Achievements of the Year
The inlet for HIgh Mach Integrated COntrol experiment; HIMICO has a variable geometry inlet andthe height of inlet throat can be changed by moving the 2nd and 3rd ramps. The inlet has a clearance
between the 2nd or 3rd ramps and the side wall to avoid interference between them. We call this sideclearance and define the width of side-clearance as wside. Numerical simulation has been conducted toinvestigate the side-clearance effect on the Inlet performance of HIMICO by comparing several cases
each of which has different wside.
(Fig.1) and (fig.2) show Mach number contours along the center line (Upper) and the line 16.5 mm
away from the center line (Lower). (Fig.1) is the case at the nozzle height =13 mm and (fig.2) is the caseat the nozzle height=9 mm. From (fig.1), we can see that a large flow separation at the 2nd ramp occurs
only when wside=1 mm at the center line. On the other hand, it occurs when wside=0.5 mm, 0.75 mm, andJAXA Supercomputer System Annual Report April 2017-March 2018

1 mm nearby the side wall and a oblique shock from the 2nd ramp leaks to out of the inlet. From (fig.2),
we can see the same flow separation when wside=0.5 mm, 0.75 mm, and 1 mm at the center line.
(Fig.3) shows performance maps each wside. The performance map of the case wside=1 mm agrees with
EFD results within 5% errors of mass capture ratio; MCR and that of the case wside=0 mm agrees withtheoretical value within 2% errors of MCR. From these results we concluded that the cause of the MCR
difference between EFD results and theoretical value is the side-clearance and the leaking to out of theinlet of an oblique shock from 2nd ramp causes the MCR reduction of EFD results compared withtheoretical value.

Fig.1 Mach Number Contour along center line (Upper) and nearby the side wall (Lower) atheight of nozzle= 13 mm

JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.2 Mach Number Contour along center line (Upper) and nearby the side wall (Lower)
at height of nozzle= 9 mm

Fig.3 Performance map

JAXA Supercomputer System Annual Report April 2017-March 2018

Publications
 Peer-reviewed papers
1) Nagao, T., et al.,"Numerical analysis on Supersonic Inlet Buzz",The Japan Society for Aeronauticaland Space Science (submitted)
 Presentations
1) Yoshida,H., et al.,"Numerical Study of Hypersonic Air Intake Aerodynamics Performance for HighMach Integrated Control Experiment "HIMICO"", AIAA Propulsion and Energy Forum 20172) Yoshida,H., et al.,"Numerical Study of Inlet Buzz Prediction for the Silent Supersonic Transport",
55th Aircraft Symposium3) SANO, M., et al.,"Influence of the side clearance on the inlet for Hi-Mach Integrated Control
Experiment (HIMICO)", Space Transportation Symposium FY2017
4) Yoshida, H., et al.,"Numerical Study of Inlet Performance with Airframe/Propulsion Interference
for High Mach Integrated Control Experiment "HIMICO"", AJCPP2018
5) SANO, M., et al.,"Numerical Analysis of Supersonic Air-Intake Buzz", Aerospace Fluid Science
Summer School 2017

JAXA Supercomputer System Annual Report April 2017-March 2018

Usage of JSS2
 Computational Information
Parallelization Methods

MPI

Thread Parallelization Methods

N/A

Number of Processes

512 - 1024

Elapsed Time per Case

12.00 hours

 Resources Used
Fraction of Usage in Total Resources*1 (%): 0.93
Details
Computing Resources
System Name

Amount of Core Time (core x hours)

Fraction of Usage*2 (%)

SORA-MA

7,438,629.22

0.99

SORA-PP

26,731.96

0.33

SORA-LM

2,995.19

1.54

SORA-TPP

0.00

0.00

File System Resources
File System Name

Storage assigned(GiB)

Fraction of Usage*2 (%)/home

495.91

0.34

/data

29,296.89

0.54

/ltmp

5,859.38

0.44

Archiver Resources
Archiver System Name

Storage used(TiB)

Fraction of Usage*2 (%)

J-SPACE

3.56

0.15

*1 Fraction of Usage in Total Resources: Weighted average of three resource types (computing, file system,
and archiver)*2 Fraction of Usage: Percentage of usage relative to each resource used in one year

JAXA Supercomputer System Annual Report April 2017-March 2018

Numerical study on unsteady flow fields around a re-entry capsule
Report Number：R17ETET12
Subject Category：Skills Acquisition System
URL：https://www.jss.jaxa.jp/ar/e2017/4471/
Responsible Representative
Takashi Takahashi, Aeronautical Technology Directorate, Numerical Simulation Research Unit

Contact Information
Kenji Kobayashi knjkoba@chofu.jaxa.jp

Members
Kenji Kobayashi

Abstract
Coherent structures around a re-entry capsule were investigated using the unsteady flow solver
FaSTAR. A re-entry capsule shows dynamic instability in subsonic and transonic speeds. This study
focused on

the subsonic unsteady flow around the capsule and investigated the mechanism of the

dynamic instability.

Reasons for using of JSS2
Large computational cost is required to simulate the unsteady flow field.

Achievements of the Year
Coherent structures around a reentry capsule at M=0.4 and 0.8 were simulated. It reproduced thefluid phenomena which had frequency of St ~ 0.01 , where St is the Strouhal number. We found thisfrequency was close to the frequency of the dynamic instability of the capsule.

JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.1 Instantaneous flow field of M = 0.4 (Iso-surface of Q-criterion))Fig.2 Frequency distribution of lift coefficientJAXA Supercomputer System Annual Report April 2017-March 2018

Publications
N/A

Usage of JSS2
 Computational Information
Parallelization Methods

MPI

Thread Parallelization Methods

N/A

Number of Processes

512

Elapsed Time per Case

700.00 hours

 Resources Used
Fraction of Usage in Total Resources*1 (%): 0.13
Details
Computing Resources
System Name

Amount of Core Time (core x hours)

Fraction of Usage*2 (%)

SORA-MA533,290.78

0.07

SORA-PP

14,231.82

0.18

SORA-LM

17,487.62

9.01

SORA-TPP

0.00

0.00

File System Resources
File System Name

Storage assigned(GiB)

Fraction of Usage*2 (%)/home

238.42

0.17

/data

42,480.49

0.79

/ltmp

976.560.07

Archiver Resources
Archiver System Name

Storage used(TiB)

Fraction of Usage*2 (%)

J-SPACE

5.80

0.25

*1 Fraction of Usage in Total Resources: Weighted average of three resource types (computing, file system,
and archiver)*2 Fraction of Usage: Percentage of usage relative to each resource used in one year

JAXA Supercomputer System Annual Report April 2017-March 2018

Environment Conscious Aircraft Systems Research in Eco-wing Technology
Report Number：R17ETET15
Subject Category：Skills Acquisition System
URL：https://www.jss.jaxa.jp/ar/e2017/4472/
Responsible Representative
Yoshikazu Makino, Aeronautical Technology Directorate Next Generation Aeronautical Innovation
Hub Center

Contact Information
Dongyoun Kwak kwak.dongyoun@jaxa.jp

Members
Hotaka Kobayashi, Yutaro Yamasaki, Dongyoun Kwak, Shihoko Endo, Hiroki Adachi, Shoya Ogino

Abstract
Innovative drag reduction technologies are investigated to reduce the fuel consumption for aconventional aircraft configuration. Aircraft noise prediction technologies and the conceptual design
technologies are also developed for future aircraft which achieve low noise and high efficiency.
http://www.aero.jaxa.jp/eng/research/ecat/ecowing/

Reasons for using of JSS2
CFD analysis are used for the understanding of aerodynamic characteristics and evaluation of theperformance in the aircraft design phase. Huge calculation resources and costs were required for thehigh fidelity and quick response CFD analysis for the optimum aerodynamic design process on complex
aircraft geometry. JSS2 can achieve those requirements, the cost and time are drastically saved on the
CFD analysis.

Achievements of the Year
Drag reduction technologies and noise reduction technologies are investigated by cooperation with
universities.
On the drag reduction technologies, two wingtip geometries were designed to reduce induced dragcomponent using numerical analysis. A downward rakelet configuration, which is a wingtip configuration
with a raked wingtip accompanied by a downward winglet section, can reduce the induced drag by reducethe interaction caused by trailing edge vortex, and reduce the wave drag by cotrolling the shock wave
caused from the corner area of the winglet. The downward rakelets with a 105% span length achieve a

JAXA Supercomputer System Annual Report April 2017-March 2018

drag reduction more than 3% compared with the baseline configuration(Fig.1). These benefits werevalidated from experimental data obtained by JAXA 2mx2m transonic wind tunnel campaign.
On the aircraft noise reduction technologies, a reduction method of airframe noise from leadingedge slat deployed at take-off/landing high-lift conditions by slat setting optimization has been
investigated. An empirical noise evaluation parameter proposed for slat setting optimization using low
cost steady RANS CFD has been validated with high-fildeity unsteady DDES CFD simulations. The
noise generation/reduction mechanisms have been investigated by the detail comparison of flowfields
and noise levels of baseline and evaluated configurations with slat settings varied and the design
knowledge toward low-noise slat has been acquired (Fig.2).

Fig.1 TRA2022 2nd configuration with a downward rakelet

Fig.2 Study on slat noise reduction by slat setting optimization and noise generation/reduction
mechanisms: (a) Three-element high-lift airfoil, (b) Visualization of unsteady flowfields(Q-criterion colored by x-vorticity) and OASPL, (c) Comparison of PSDs of m

JAXA Supercomputer System Annual Report April 2017-March 2018

Publications
 Non peer-reviewed papers
1) Yuhara, T., Kubota, K. and Rinoie, K., "Drag Divergence Characteristics of Winglets", AIAA
SciTech 2018, AIAA Paper 2018-0046.

Usage of JSS2
 Computational Information
Parallelization Methods

MPI

Thread Parallelization Methods

OpenMP

Number of Processes

15 - 50

Elapsed Time per Case

300.00 hours

 Resources Used
Fraction of Usage in Total Resources*1 (%): 0.18
Details
Computing Resources
System Name

Amount of Core Time (core x hours)

Fraction of Usage*2 (%)

SORA-MA

1,038,242.42

0.14

SORA-PP

14,889.15

0.19

SORA-LM

8.52

0.00

SORA-TPP

0.00

0.00

File System Resources
File System Name

Storage assigned(GiB)

Fraction of Usage*2 (%)/home

889.49

0.62

/data

22,837.66

0.42

/ltmp

20,833.34

1.57

Archiver Resources
Archiver System Name

Storage used(TiB)

Fraction of Usage*2 (%)

J-SPACE

62.92

2.71

*1 Fraction of Usage in Total Resources: Weighted average of three resource types (computing, file system,
and archiver)*2 Fraction of Usage: Percentage of usage relative to each resource used in one year

JAXA Supercomputer System Annual Report April 2017-March 2018

Research of Lattice Boltzmann Method
Report Number：R17ETET17
Subject Category：Skills Acquisition System
URL：https://www.jss.jaxa.jp/ar/e2017/4473/
Responsible Representative
Takashi Aoyama, Aeronautical Technology Directorate, Numerical Simulation Research Unit

Contact Information
Takashi Ishida ishida.takashi@jaxa.jp

Members
Toru Yamaya, Daichi Asaoka

Abstract
The purpose of this research is to construct a collision model considering the influence of bulk viscosityand verify the stability in high Reynolds number flow analysis. In order to compare the computational
stability and calculation time using SRT (Single-Relaxation Time) w/o bulk viscosity, the calculation of
2-dimensional shear layer flow was carried out for the verification. It is found that SRT with bulk viscosity
improves the stability and accuracy even at low grid-resolution.

Reasons for using of JSS2
The computational cost of unsteady flow simulation by LBM is very high.
We use JSS2 to reduce the computational cost by paralleization.

Achievements of the Year
By adding the influence of bulk viscosity to SRT,the computation stability and accuracy was

improved even in the case of high Reynolds number flow and low grid-resolution.

JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.1 2-dimensional shear layer flow (Reynolds number 10,000)

Publications
 Presentations
1) Toru Yamaya, "Performance evaluation of collision model on Lattice Boltzmann Method",Computational Fluid Dynamics symposium 2016, B06-1.
2) Toru Yamaya, "Numerical simulation of unsteady flows with LBM and statistics comparison of flow
fields", Computational Fluid Dynamics symposium 2017, D08-1.

JAXA Supercomputer System Annual Report April 2017-March 2018

Usage of JSS2
 Computational Information
Parallelization Methods

MPI

Thread Parallelization Methods

OpenMP

Number of Processes

2Elapsed Time per Case

90.00 seconds

 Resources Used
Fraction of Usage in Total Resources*1 (%): 0.34
Details
Computing Resources
System Name

Amount of Core Time (core x hours)

Fraction of Usage*2 (%)

SORA-MA

2,528,479.04

0.34

SORA-PP

0.00

0.00

SORA-LM

0.00

0.00

SORA-TPP

0.00

0.00

File System Resources
File System Name

Storage assigned(GiB)

Fraction of Usage*2 (%)/home

486.37

0.34

/data

48,923.51

0.90

/ltmp

3,906.25

0.29

Archiver Resources
Archiver System Name

Storage used(TiB)

Fraction of Usage*2 (%)

J-SPACE

0.00

0.00

*1 Fraction of Usage in Total Resources: Weighted average of three resource types (computing, file system,
and archiver)*2 Fraction of Usage: Percentage of usage relative to each resource used in one year

JAXA Supercomputer System Annual Report April 2017-March 2018

Air flow distribution control by a fluidic element
Report Number：R17ETET18
Subject Category：Skills Acquisition System
URL：https://www.jss.jaxa.jp/ar/e2017/4474/
Responsible Representative
Takashi Yamane, Aeronautical Technology Directorate, Propulsion Research Unit

Contact Information
Seiji Yoshida yoshida.seiji@jaxa.jp

Members
Seiji Yoshida(JAXA), Mitsumasa Makida(JAXA), Naoki Nakamura(ASIRI),
Takeishi Ikumi(Waseda univ.)

Abstract
Lean combustion is promising to reduce nitrogen oxide emission from jet-engines. To solve
combustion instability, that is a problem of lean combustion, a pilot burner for ensuring stablecombustion and a main burner for performing lean, low-NOx combustion are used. The purpose of thisstudy is improvement of combustor performance by controlling air flow rate distribution between thepilot burner and the main burner using a fluidic element, which has no moving part.
http://www.aero.jaxa.jp/eng/research/basic/propulsion/advanced-core-engine/

Reasons for using of JSS2
It is necessary that numerous CFD analysis about geometry of fluidic elements to optimize its geometry.

Achievements of the Year
In order to improve the characteristics of the fluidic elements, numerical analysis were conducted formore than 25 computational grids of the fluidic element with different flow channel shape. As a result,by changing both the shape and position of the splitter that separates the two outlet flow channels, it was
confirmed that the main flow jet was bent at the tip of the splitter, and the performance target of thefluidic elements could be achieved.

JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.1 Visualization of streamlines inside the fluidic elements before changing
the splitter shapeFig.2 Visualization of streamlines inside the fluidic elements after changing
the splitter shape

Publications
N/A

JAXA Supercomputer System Annual Report April 2017-March 2018

Usage of JSS2
 Computational Information
Parallelization Methods

MPI

Thread Parallelization Methods

Automatic Parallelizatio

Number of Processes

36

Elapsed Time per Case

50.00 hours

 Resources Used
Fraction of Usage in Total Resources*1 (%): 0.14
Details
Computing Resources
System Name

Amount of Core Time (core x hours)

Fraction of Usage*2 (%)

SORA-MA

1,115,250.61

0.15

SORA-PP

915.970.01

SORA-LM

0.00

0.00

SORA-TPP

0.00

0.00

File System Resources
File System Name

Storage assigned(GiB)

Fraction of Usage*2 (%)/home

104.37

0.07

/data

3,158.78

0.06

/ltmp

3,472.22

0.26

Archiver Resources
Archiver System Name

Storage used(TiB)

Fraction of Usage*2 (%)

J-SPACE

0.14

0.01

*1 Fraction of Usage in Total Resources: Weighted average of three resource types (computing, file system,
and archiver)*2 Fraction of Usage: Percentage of usage relative to each resource used in one year

JAXA Supercomputer System Annual Report April 2017-March 2018

Study of numerical simulation for three-dimensional buffet
Report Number：R17ETET21
Subject Category：Skills Acquisition System
URL：https://www.jss.jaxa.jp/ar/e2017/4475/
Responsible Representative
Takashi Aoyama, Aeronautical Technology Directorate, Numerical Simulation Research Unit

Contact Information
Atsushi Hashimoto hashimoto.atsushi@jaxa.jp

Members
Yoimi Kojima, Yoichi Saito

Abstract
Shock-wave/boundary layer interaction on the suction side of the wing at high Mach number and/or
high angle of attack leads to large scale self-sustained motion of the shock wave. This phenomenon iscalled transonic buffet. The buffet leads to dangerous structural vibrations.
There are many studies of the buffet on a two-dimensional wing which have a uniform shape in the
spanwise direction. On the other hand, there are not many studies on the buffet on a three-dimensional
wing which resembling realistic aircraft. Several studies have reported that an oscillation of the shockpropagates in the spanwise direction on a three-dimensional wing, but its mechanism is not wellunderstood.
The purpose of our project is to clarify the mechanism of the buffet in a three-dimensional wing. The
buffet on parallelogram wings with different sweep angle were simulated. As a result, the propagation ofshock oscillation in the spanwise direction was simulated. In addition, it was observed that the
propagation of the pressure wave in the chordwise direction.

Reasons for using of JSS2
Three-dimensional buffet is a complicated unsteady flow, and its simulation requires large scalecalculation resources. Therefore, use of supercomputer is indispensable. Also, large capacity memory is
required for analyzing large scale calculation results. Therefore, JSS 2 was used for execution ofnumerical simulation and analyzing of unsteady data.

Achievements of the Year
(Fig. 1) and (Fig. 2) are movies of surface pressure coefficients in cases with sweep angle of 0 degrees
and 15 degrees, respectively. In Fig. 1, the shock front oscillates in the chordwise direction. The

JAXA Supercomputer System Annual Report April 2017-March 2018

oscillation is uniform in the spanwise direction and this is a two-dimensional phenomenon. On the other
hand, in Fig. 2, it can be observed that an oscillation of the shock propagates in the spanwise direction,
which is a three-dimensional phenomenon. In addition, the propagation occurs from around of the midspan of the wing.
We observed pressure waves (Kutta wave) generated from the trailing edge of the wing in the case of
sweep angle of 15 degrees (Fig. 3). The caption in Fig. 3 indicates dimensionless time. In Fig. 3, it canbe observed that the Kutta wave is parallel to the trailing edge and is propagating in the chordwise
direction.
In this study, the three-dimensional buffet was well simulated. We also observed propagation of Kutta
waves generated at the trailing edge in the chordwise direction.

Fig.1 Time variation of surface pressure fluctuation (AoS 0 degrees)Fig.2 Time variation of surface pressure fluctuation (AoS 15 degrees)JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.3 Propagation of Kutta waves generated at the trailing edge

Publications
 ■ Peer-reviewed papers
1) Yoimi Kojima, Atsushi Hashimoto, Takashi Aoyama and Masaharu Kameda, "Variation in
Spanwise Direction of Transonic Buffet on a Three-dimensional Wing," Journal of the Japan
Society for Aeronautical and Space Sciences, Vol. 66, No. 1, pp. 39-45, (2018). (In japanese) Presentations
1) Yoimi Kojima, Atsushi Hashimoto, Takashi Aoyama and Masaharu Kameda,"Variation in

spanwise direction of transonic buffet on a three-dimensional wing," 31st International symposium
on shock waves, Nagoya, Japan, (2017).

JAXA Supercomputer System Annual Report April 2017-March 2018

Usage of JSS2
 Computational Information
Parallelization Methods

MPI

Thread Parallelization Methods

N/A

Number of Processes

320

Elapsed Time per Case

60.00 hours

 Resources Used
Fraction of Usage in Total Resources*1 (%): 0.92
Details
Computing Resources
System Name

Amount of Core Time (core x hours)

Fraction of Usage*2 (%)

SORA-MA

7,331,969.95

0.96

SORA-PP

40,867.27

0.51

SORA-LM

180.590.09

SORA-TPP

0.00

0.00

File System Resources
File System Name

Storage assigned(GiB)

Fraction of Usage*2 (%)/home

104.90

0.07

/data

19,531.26

0.36

/ltmp

3,906.25

0.29

Archiver Resources
Archiver System Name

Storage used(TiB)

Fraction of Usage*2 (%)

J-SPACE

93.24

4.01

*1 Fraction of Usage in Total Resources: Weighted average of three resource types (computing, file system,
and archiver)*2 Fraction of Usage: Percentage of usage relative to each resource used in one year

JAXA Supercomputer System Annual Report April 2017-March 2018

Research on combustor simulation
Report Number：R17ETET23
Subject Category：Skills Acquisition System
URL：https://www.jss.jaxa.jp/ar/e2017/4476/
Responsible Representative
Takashi Aoyama, Aeronautical Technology Directorate, Numerical Simulation Research Unit

Contact Information
Rui Toyonaga toyonaga.l.0121@ruri.waseda.jp

Members
Rui Toyonaga

Abstract
For the development of a jet engine combustor with high environmental compatibility, we develop the
combustion calculation code that can capture the pressure propagation and chemical reaction withpractical calculation cost. In addition, a verification calculation of this calculation code is conducted on
the scramjet test engine of DLR.

Reasons for using of JSS2
It is necessary to use supercomputer to conduct development and verification of the combustion
calculation code.

Achievements of the YearIn this research, the implementation of the combustion calculation code based on compressible flamelet
model to a density- based fluid analysis solver, FaSTAR (FAST Aerodynamic Routines) was conducted.
Then, an artificial neural network (ANN) model was applied to reduce the calculation cost whenreferring to the flamelet library. The ANN model has 2 input units (mixture fraction and scalardissipation rate), 3 hidden units, and output units corresponding to mass fraction of each chemical
species (As an example, Fig.1 shows the ANN model of OH mass fraction). In addition, we introduced
the variance of the mixing fraction to the Flamelet library, which was conventionally obtained by mixing
fraction and scalar dissipation rate. By this, the effect of turbulence of each species mass fraction was
taken into account, and the precision of the Flamelet library has been improved (Fig2: Extension of theFlamelet library by the probability probability function method).

JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.1 OH mass fraction generated by ANN

Fig.2 Extension of the Flamelet library by the probability probability function method

Publications
 Non peer-reviewed papers
1) Rui Toyonaga, Himeko Yamamoto, Yasuhiro Mizobuchi, Tetsuya Sato, Numerical investigation onsupersonic combustion in SCRAMJET engine by FaSTAR, JAXA Special Publication, 2017.12
2) Himeko Yamamoto, Rui Toyonaga, Yasuhiro Mizobuchi, Tetsuya Sato, Numerical analysis of jet
lifted flames using G- equation, JAXA Special Publication, 2017.12

JAXA Supercomputer System Annual Report April 2017-March 2018

 Presentations
1) Himeko Yamamoto, Rui Toyonaga, Yasuhiro Mizobuchi, Tetsuya Sato, Numerical study on flame
structure of jet lifted flames by FaSTAR, 57th Aerospace Propulsion Conference of Japan Society
for Aeronautical and Space Science, 2017.3
2) Himeko Yamamoto, Rui Toyonaga, Yasuhiro Mizobuchi, Tetsuya Sato, Numerical analysis of jet
lifted flames using G- equation, 49th Fluid Dynamics Conference/ 35th Aerospace Numerical
Simulation Symposium, 2017.6
3) Himeko Yamamoto, Rui Toyonaga, Yusuke Komatsu, Koki Kabayama, Yasuhiro Mizobuchi, Tetsuya
Sato, Improvement of compressible flamelet model using artificial neural network, The Asian Joint
Conference on Propulsion and Power, 2018.3

JAXA Supercomputer System Annual Report April 2017-March 2018

Usage of JSS2
 Computational Information
Parallelization Methods

MPI

Thread Parallelization Methods

N/A

Number of Processes

2 - 1024

Elapsed Time per Case

150.00 hours

 Resources Used
Fraction of Usage in Total Resources*1 (%): 0.22
Details
Computing Resources
System Name

Amount of Core Time (core x hours)

Fraction of Usage*2 (%)

SORA-MA

1,746,759.24

0.23

SORA-PP

980.730.01

SORA-LM

361.16

0.19

SORA-TPP

0.00

0.00

File System Resources
File System Name

Storage assigned(GiB)

Fraction of Usage*2 (%)/home

476.84

0.33

/data

9,765.63

0.18

/ltmp

1,953.13

0.15

Archiver Resources
Archiver System Name

Storage used(TiB)

Fraction of Usage*2 (%)

J-SPACE

0.00

0.00

*1 Fraction of Usage in Total Resources: Weighted average of three resource types (computing, file system,
and archiver)*2 Fraction of Usage: Percentage of usage relative to each resource used in one year

JAXA Supercomputer System Annual Report April 2017-March 2018

Study on Aerodynamics of Space Plane
Report Number：R17ETET24
Subject Category：Skills Acquisition System
URL：https://www.jss.jaxa.jp/ar/e2017/4477/
Responsible Representative
Yusuke Maru, Department of Space Flight Systems, Institute of Space and Astronautical Science

Contact Information
Yusuke Maru maru.yusuke@jaxa.jp

Members
Mafuyu Imai, Tomoya Mukai

Abstract
Conducting aerodynamic design and evaluation of aerodynamic characteristics on space plane carrying
amor breathing engines with CFD simulations.

Reasons for using of JSS2
Simulation environment is arranged well. And also, CFD software is substantial.

Achievements of the Year
CFD simulations have been carried out using "Fluent".
In order to confirm the validity of CFD, CFD simulation was performed on the shape of which windtunnel experiment was performed and the results were compared. A consistent result was obtained forlift and drag. (fig.1)
We are considering to apply the concept of wave rider to the aerodynamic shape of space planes. In
wave rider, we considered improvement of performance at non-design Mach number by changing
aerodynamic shape, and evaluated its effect and characteristics by CFD. By bending the tip of the wing
to approach the shock wave surface, we considered to improve the performance below the design Mach
number, however the performance did not change very much. While, it showed that the performance canbe improved at above design Mach number by contracting the wings. (fig.2)

JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.1 Comparison in lift and drag coefficients between experiment and CFD

Fig.2 effect of aerodynamic shape deformation on lift-drag ratio

JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.3 relationship between shock wave surface and wing tip

Publications
 Presentation
1) Mafuyu Imai, Hiroyasu Manako, Yusuke Maru, Shujiro Sawai, "Study on improvement of off-design
performance of wave riders by aerodynamic shape deformation", 61st UKAREN, 2J14, Niigata,
2017/102) Mafuyu Imai, Hiroyasu Manako, Yusuke Maru, Shujiro Sawai, "Study on off-design aerodynamic
performance of wave riders", Symposium on dynamics for space flight 2017, Sagamihara, 2017/12
 Others
1) Mafuyu Imai, Study on aerodynamic performance of space planes, Master's thesis, Teikyo
University, 2018

JAXA Supercomputer System Annual Report April 2017-March 2018

Usage of JSS2
 Computational Information
Parallelization Methods

N/A

Thread Parallelization Methods

N/A

Number of Processes

1

Elapsed Time per Case

10.00 hours

 Resources Used
Fraction of Usage in Total Resources*1 (%): 0.00
Details
Computing Resources
System Name

Amount of Core Time (core x hours)

Fraction of Usage*2 (%)

SORA-MA

0.00

0.00

SORA-PP

0.00

0.00

SORA-LM

0.00

0.00

SORA-TPP

0.00

0.00

File System Resources
File System Name

Storage assigned(GiB)

Fraction of Usage*2 (%)/home

019.07

0.01

/data

190.73

0.00

/ltmp

3,906.25

0.29

Archiver Resources
Archiver System Name

Storage used(TiB)

Fraction of Usage*2 (%)

J-SPACE

0.00

0.00

*1 Fraction of Usage in Total Resources: Weighted average of three resource types (computing, file system,
and archiver)*2 Fraction of Usage: Percentage of usage relative to each resource used in one year

JAXA Supercomputer System Annual Report April 2017-March 2018

Study of calculation method for chemical reactions in turbulent combustion
Report Number：R17ETET25
Subject Category：Skills Acquisition System
URL：https://www.jss.jaxa.jp/ar/e2017/4478/
Responsible Representative
Takashi Aoyama, Aeronautical Technology Directorate, Numerical Simulation Research Unit

Contact Information
Yusuke Komatsu ksw.koma2@asagi.waseda.jp

Members
Yusuke Komatsu

Abstract
For the purpose of realization of hypersonic transport, research and development aiming atdemonstration of integrated control technology for aircraft / propulsion under hypersonic conditions isunder way. It is difficult to acquire the data necessary for the performance evaluation of the ramjet engine
mounted on the experimental aircraft only by the combustion test. Therefore, numerical analysis isnecessary to interpolate the experimental data and to understand the phenomena in the combustor. Then,
we develop a reacting flow solver with detailed chemical kinetics based on the CFD solver FaSTAR
developed by JAXA. In addition, a verification calculation of this solver is conducted on the twodimensional shape.

Reasons for using of JSS2
When numerical analysis including chemical reactions is performed on the actual combustor scale, thecalculation cost becomes very large. Therefore, we used JSS2 which can parallelize.

Achievements of the YearWe developed a reacting flow solver with detailed chemical kinetics by implementing species transport
equations and Arrhenius equation in the CFD solver FaSTAR developed by JAXA. We also implemented
a time integration method combining LU-SGS method and Point-Implicit method.
Numerical analysis was carried out with this solver for the premixed flow in the two-dimensional
channel as a verification calculation, and the result quantitatively agreed with the analytical solution(Fig.
1). In addition, in the analysis of the supersonic diffusion combustion experiment conducted by Burrows
and Kurkov, relatively large errors occurred in the distribution of species mass fraction and temperature,
but their maximum values agreed with the experimental results(Fig. 2, 3).

JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.1 O2 mass fractions along the main flow direction(line : Numerical solution, plot : analytical solution)

Fig.2 Static temperature contours in test section

Fig.3 H2O mole fractions and total temperature at test section exit

Publications
N/A

JAXA Supercomputer System Annual Report April 2017-March 2018

Usage of JSS2
 Computational Information
Parallelization Methods

MPI

Thread Parallelization Methods

N/A

Number of Processes

32 - 64

Elapsed Time per Case

120.00 hours

 Resources Used
Fraction of Usage in Total Resources*1 (%): 0.68
Details
Computing Resources
System Name

Amount of Core Time (core x hours)

Fraction of Usage*2 (%)

SORA-MA

5,618,850.84

0.75

SORA-PP

3,882.99

0.05

SORA-LM

1.60

0.00

SORA-TPP

0.00

0.00

File System Resources
File System Name

Storage assigned(GiB)

Fraction of Usage*2 (%)/home

476.84

0.33

/data

9,765.63

0.18

/ltmp

1,953.13

0.15

Archiver Resources
Archiver System Name

Storage used(TiB)

Fraction of Usage*2 (%)

J-SPACE

0.00

0.00

*1 Fraction of Usage in Total Resources: Weighted average of three resource types (computing, file system,
and archiver)*2 Fraction of Usage: Percentage of usage relative to each resource used in one year

JAXA Supercomputer System Annual Report April 2017-March 2018

Numerical study on

low-speed buffet
Report Number：R17ETET26
Subject Category：Skills Acquisition System
URL：https://www.jss.jaxa.jp/ar/e2017/4479/

Responsible Representative
Takashi Aoyama, Aeronautical Technology Directorate, Numerical Simulation Research Unit

Contact Information
Masashi Kanamori kanamori.masashi@jaxa.jp

Members
Masashi Kanamori, Takahiro Yoshikawa

Abstract
It is of a great importance to predict a so-called low-speed buffet phenomenon for realizing safer flight.
During a flight with a high angle-of-attack condition in a low-speed regime, separated flow at a leadingedge of main wing impinges on its tail, resulting in a hazardous vibration. Our research group works ona preliminary study on low-speed buffet by means of computational fluid dynamics (CFD) in order tograsp the essence of the phenomenon.

Reasons for using of JSS2
It is absolutely necessary to prepare a computational grid with high-resolution near the separated zone
in order to predict a low-speed buffet phenomenon accurately. The number of grid point is of the orderof tens of millions, which is prohibitively large from a view point of a computation with a personal
computer. The processing capability of JSS2 is therefore necessary for our research.

Achievements of the Year
Two models were considered in this study; NASA Common Research Model (NASA CRM) as model 1
and the same model without main wing as model 2 as shown in (Fig.1). Comparison of flowfield aroundeach model were conducted by carefully calculating the effective angle of attack of the tail by subtracting
a downwash from a flow velocity in the flowfield around model 1. (Fig. 2) presents a variation of lift
coefficient of the tail against its effective angle of attack, clearly showing an apparent difference in lift
coefficient at angle of attack of 8 degrees, at which model 1 began to stall. This indicates a clear
correlation between a stall of main wing and a sharp drop of the lift of a tail.

JAXA Supercomputer System Annual Report April 2017-March 2018

Fig.1 model 1 and model 2

Fig.2 variation of lift coefficient of tail against effective angle of attack

Publications
N/A

JAXA Supercomputer System Annual Report April 2017-March 2018

Usage of JSS2
 Computational Information
Parallelization Methods

MPI

Thread Parallelization Methods

N/A

Number of Processes

512

Elapsed Time per Case

12.00 hours

 Resources Used
Fraction of Usage in Total Resources*1 (%): 0.20
Details
Computing Resources
System Name

Amount of Core Time (core x hours)

Fraction of Usage*2 (%)

SORA-MA

1,585,547.03

0.21

SORA-PP

864.950.01

SORA-LM

929.75

0.48

SORA-TPP

0.00

0.00

File System Resources
File System Name

Storage assigned(GiB)

Fraction of Usage*2 (%)/home

476.84

0.33

/data

9,765.63

0.18

/ltmp

1,953.13

0.15

Archiver Resources
Archiver System Name

Storage used(TiB)

Fraction of Usage*2 (%)

J-SPACE

0.00

0.00

*1 Fraction of Usage in Total Resources: Weighted average of three resource types (computing, file system,
and archiver)*2 Fraction of Usage: Percentage of usage relative to each resource used in one year