JAXA Special Publication JAXA-SP-19-003E

Technical Training on High-Speed Rotorcraft
Report Number: R18ETET04
Subject Category: Skills Acquisition System
URL: https://www.jss.jaxa.jp/en/ar/e2018/9165/
Responsible Representative
Yasutada Tanabe, Aeronautical Technology Directorate, Aircraft Systems Research Unit
Contact Information
Dr. Yasutada Tanabe, Aircraft Systems Research Unit, Aeronautical Technology Unit, JAXA
(tanabe.yasutada@jaxa.jp)
Members
Yasutada Tanabe, Hideaki Sugawara, Kaito Hayami, Yusuke Hamamoto
Abstract
Research on the aerodynamic interference of the rotor and wing on the high-speed rotorcraft. Study of theaerodynamic characteristics of a coaxial rotor.
Ref. URL: http://www.aero.jaxa.jp/eng/research/frontier/rotary/
Reasons for using JSS2
This study needed the computational high performance with the rotorcraft analysis code rFlow3d which wasdeveloped by JAXA.
Achievements of the YearWe performed CFD analysis with the rFlow3D where the computational mesh of the rotor and wing are shownin Fig. 1. Fig. 2 shows the interference of the rotor downwash on the wing at advance ratio 0.3. Strong interferenceof rotor downwash on the wing at advance ratio 0.7 is also confirmed.
In thrust variations of the coaxial rotors, different fluctuations are observed as compared with the single rotor.
Two characteristics fluctuations, one is the high-frequency vibration and another one is the low-frequency
vibration, are observed for the coaxial rotor. The high frequencies are caused by pressure interactions at crossing
the coaxial rotor blades as shown in Fig. 3. The cause of low-frequency fluctuations are the interactions between
the blades and the tip vortices generated by the preceding blades as shown in Fig. 4.

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JAXA Supercomputer System Annual Report (April 2018-March 2019)

Fig. 1: Computational Mesh of Rotor and Wing

Fig. 2: Vertical Velocity Distribution around Rotor and Wing in Side View:
Advance Ratio = 0.3－329－This document is provided by JAXA.

JAXA Special Publication JAXA-SP-19-003E

Fig. 3: Distribution of pressure coefficient at blade crossing for a coaxial rotor.
The pressure below the upper rotor is less than the lower one. This phenomena
causes adrupt decrease of system thrust.

Fig. 4: Visualization of the tip vortex generated by a coaxial rotor in forward flight.
The contour on vortex is nondimensionalized (by the sound velocity) flow rate. BladeVortex Interactions (BVI) are observed. BVI are the causes of thrust fluctuations.

Publications- Non peer-reviewed papers
1) Hiroki Oshima, Takeshi Akasaka, Yusuke Hamamoto, Noboru Kobiki and Yasutada Tanabe, Experimental
Investigation of Aerodynamic Interaction Between the Rotor-Tapered Wings at Hover on a Compound Helicopter,
56th JSASS Aircraft Symposium, Yamagata Telsa, November 14-16, 2018, Paper No. JSASS-2018-5166. (inJapanese)2) Ryo Hayakawa, Takeshi Akasaka, and Yasutada Tanabe, Numerical Study of Rotor/Wing Interaction on aCompound Helicopter in High Advance Ratio, 56th JSASS Aircraft Symposium, Yamagata Telsa, November 1416, 2018, Paper No. JSASS-2018-5167. (in Japanese)－330－

This document is provided by JAXA.

JAXA Supercomputer System Annual Report (April 2018-March 2019)

Usage of JSS2


Computational Information
Process Parallelization Methods

N/A

Thread Parallelization Methods

OpenMP

Number of Processes

1

Elapsed Time per Case

36000 Second (s)Resources Used
Fraction of Usage in Total Resources*1 (%): 0.41
Details
Computational Resources
System Name

Amount of Core Time(core x hours)

Fraction of Usage*2 (%)

SORA-MA

330,635.65

0.04

SORA-PP

396,824.58

3.17

SORA-LM

0.00

0.00

SORA-TPP

142,239.75

10.40

File System Resources
File System Name

Storage Assigned (GiB)

Fraction of Usage*2 (%)/home

540.42

0.56

/data

22,786.47

0.40/ltmp

4,340.28

0.37

Archiver Resources
Archiver Name

Storage Used (TiB)

J-SPACE

Fraction of Usage*2 (%)
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.

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This document is provided by JAXA.