Numerical Flow Designing Co., Ltd.
1-10-7 Higashi-Gotanda, Shinagawa-ku,
Tokyo 141-0022 JAPANE-mail: info@nufd.jp URL : http: //www.nufd.jp

Fluid Dynamics Simulation software: The Next Generation

Next-generation IT program of MEXT/Revolutionary Simulation Software project
Entity Developer：Institute of Industrial Science, the University of Tokyo

NuFD/Front
FlowRedNuFD/FrontFlowRed
Large Eddy Simulation (LES) can be conducted by using high performance computing (HPC)
techniques for turbulence simulation in engineering fields. The unstructured-grid LES code
“ NuFD/FrontFlowRed ” based on the finite volume method (FVM) is optimized for the execution onHPC. “ NuFD/FrontFlowRed ” provides not only turbulence simulation, but also simulation for thecomplex multi-physics problems, such as turbulent combustion, multi-phase flow and so on.
Details reaction model

Flow oscillation

For accurate analysis with combustion, two or more reaction models
are needed. A sample simulation of diffuse flame of a co-axial jetburner is shown, considered with 9 chemical species and 21 elementary reaction formulae.
Temperature/velocity vector
General axial-symmetriclaminar diffusion flame isrecognized.
Radical OH
Radical-OH exists
mainly around interfaceof oxidizer and fuel ofdiffusion flamelet
Products H2O
Without changing chemically, H2O is spreadingfrom reaction zone.

temperature[K]velocity vector[m/s]mass fraction of OH[-]

mass fraction of H2O[-]

Large-Scale Simulation of
Spray Combustion
Right figure shows the snapshot of temperature anddroplets in spray combustion.
The simulation isdone by using 50
million grids meshand 2 million droplet
particles withflamelet model.
（Cooperative development withDr. Eng. Ryoichi Kurose,
Associate Professor,Dept. of Mechanical Engineering &Science, Kyoto University.）

Flame temperature and droplet distribution inspray combustion

High Performance Computation
The main purpose of thissimulation is to evaluate thevalidity of LES, as an alternative
to the conventional wind tunnel
testing as well as the RANS
method for the foreseeable future,to the aerodynamic assessment ofautomobiles.
“NuFD/FrontFlowRed” wasintensively optimized for the Earth
Simulator, and finally we could
successfully conduct the simulation on the parallel environment
using 100 nodes/800 CPUs.

（Institute of Industrial Science, the University Tokyo）

Turbulence analysis result ofT-junction composed ofunstructured-grid is shown.
Fully-developed turbulence
flows from the main pipe andthe branch.

water
0.23 [m/s]321.15 [K]Re=41937

water
1.0 [m/s]
306.15 [K]Re=60779

It is well known that the flowof jet from the branch into themixing region can be classified
to 4 following patterns troughflow visualizing experiments.
Velocity vector[m/s]1) wall jet flow2) reattaching jet flow3) deflected jet4) impinging jetThis analysis result isconsistent with the experimental results corresponding toTemperature[K]impinging jet.

Flamelet model
By adopting 2-scalar flamelet model (massfraction equation and G-equation for premixedflame model), “NuFD/FrontFlowRed” provides
complex unstable flow analysis with diffusionand premixed flame. For examples,“NuFD/FrontFlow Red” can compute lifted flamein turbulence and flame stabilization mechanism
by interference from vortex and flame

Two-phase flow/cavitation
simulation for problem of siphon
As to two-phase flow model,（for DMW CORPORATION）“NuFD/FrontFlowRed” will provide two-fluid flow model
based on phase separation method and VOF/level-set method by interface-tracking
method. With demands from analysis targets, “NuFD/FrontFlowRed” can computegas-liquid two phase flow, free surface flow, compressible cavitation and so on.

Features●high parallelization/vectorization for large-scale computations●modern turbulence models (LES/RANS)●flexible with compressible/incompressible scheme●pulverized coal/spray combustion with particle tracking method●LES flamelet models for diffusion, premixed andpartial-premixed flames●sound pressure level predictions with turbulence noise models●coupling radiative andconvective heat transfer using real gas model●two phase flow with complicated physical phenomenon●assessment of wind environment andair-diffusion simulation based on meteorological model●polyhedral mesh support●data import/export for many meshes and visualization tools