General-purpose thermal fluid modeling software for analyzing large flow fields with complicated geometries, like those arising in studies of gas turbines or automobile aerodynamics

About Software

What is FrontFlow/red-HPC?

FrontFlow/red-HPC is a general-purpose software package for thermal fluidsanalysis. This package began as the FrontFlow/red-HPC Ver.3.0 component of the RSS21 free software suite developed as part of the Revolutionary Simulation Software (RSS21) program operated by Japan’s Ministry of Education, Culture, Sports, Science and Technology (MEXT) for the purpose of designing next-generation IT platforms. Later, the package was further developed and improved by researchers at Hokkaido University and Japan’s RIKEN Center for Computational Science involved in Strategic Programs for Innovative Research Field No. 4: Industrial Innovations and other programs. The software library was specifically developed to accommodate a broad range of usage environments—from standard desktop workstations to next-generation supercomputers—and is widely used by scientists and industrial R&D teams specializing in engineering and manufacturing.


Features of FrontFlow/red-HPC

FrontFlow/red-HPC is a package for solving the equations that govern thermal fluid phenomena. The package, which uses unstructured grids to ensure efficient representation of complicated geometries, is designed with the specific goal of accommodating problems spanning the full spectrum of computational complexity—from simple studies appropriate for small PC clusters to large-scale calculations on next-generation supercomputers. The code is designed to exploit computational efficiencies not only when running on supercomputers such as the K-computer or Fujitsu’s FX10, but also on ordinary computers such as Intel-based desktop workstations—a feature made possible by a collaborative development process in which contributions to the code base are made not only by RIKEN personnel, but also by scientists from various universities who are users of the code, as well as commercial software developers.

Why do engineers and researchers choose to use FrontFlow/red-HPC?

FrontFlow/red-HPC not only solves the steady-state problem arising in the well-known RANS (Reynolds-Averaged Navier-Stokes) formulation—a conventional technique that has long been used in engineering problems—but also offers the option for numerical modeling in the LES (Large Eddy simulation) framework, enabling highly accurate predictions of unsteady phenomena exhibiting temporal variation on various timescales. Because FrontFlow/red-HPC can execute these numerical modeling procedures efficiently on parallel-computing architectures, it has become widely used for problems involving large-scale physical phenomena of extreme complexity, including automobile aerodynamics, combustion in gas turbines, and wind-flow trajectories in urban environments. In addition, FrontFlow/red-HPC is designed to be readily extensible, easily accommodating the addition of new analytical models, new methods, and new ideas—and thus serving as a powerful testing ground for computational experiments, both in practical design projects and in basic research. This makes FrontFlow/red-HPC a valuable platform not only for industrial engineers but for university researchers as well. A commercial edition, based on Ver.3.0, is under active development; it adds a variety of new features—enabling several new methods—and offers options for utilizing sophisticated technological services. As just one example of the capabilities of FrontFlow/red-HPC, a team of researchers from RIKEN and Kobe University recently completed a successful study of automobile aerodynamics using a model that not only incorporated the motion of the vehicle body but even took into account the response of the driver—factors that no previous software package could possibly have handled.

Performance data

The following plot shows measured results for weak-scaling tests conducted on the K-computer (16384 cores, parallelization efficiency 96.5%).


Publications resulting from this research

Research Papers published in Academic Journals

1. Makoto Tsubokura, Kozo Kitoh, Nobuyuki Oshima, Takuji Nakashima, Huilai Zhang, Keiji Onishi, Toshio Kobayashi: Large Eddy Simulation of Unsteady Flow around a Formula Car on Earth Simulator, SAE 2007 Transactions Journal of Passenger Cars : Mechanical Systems, Section 6, volume 116, pp. 40-49, 2007-01-0106(2007).

2. Makoto Tsubokura, Toshio Kobayashi, Takuji Nakashima, Takahide Nouzawa, Takaki Nakamura, Huilai Zhang, Keiji Onishi, and Nobuyuki Oshima: Computational Visualization of Unsteady Flow around Vehicles Using High Performance Computing, Computers & Fluids, vol.38, pp.981-990 (2009).

3. Takuji Nakashima, Makoto Tsubokura, Takahide Nouzawa, Takaki Nakamura, Masashi Ichimiya: Flow Structures above the Trunk Deck of Sedan-Type Vehicles and Their Influence on High-Speed Vehicle Stability, 2nd Report: Numerical Investigation on Simplified Vehicle Models using Large-Eddy Simulation, SAE International Journal of Passenger Cars – Mechanical Systems, 2(1), pp.157-167(2009).

4. Makoto Tsubokura, Takuji Nakashima, Kozo Kitoh, Yoshihiro Sasaki, Nobuyuki Oshima, Toshio Kobayashi: Development of an Unsteady Aerodynamic Simulator Using Large-Eddy Simulation Based on High-Performance Computing Technique, SAE International Journal of Passenger Cars – Mechanical Systems, 2(1), pp.168-178(2009).

5. Makoto Tsubokura, Takuji Nakashima, Masashi Kitayama,Yuki Ikawa, Deog Hee Doh, Toshio Kobayashi: Large Eddy Simulation on the Unsteady Aerodynamic Response of a Road Vehicle in Transient Crosswinds, International Journal of Heat and Fluid Flow, vol.31, pp.1075-1086 (2010).

6. Seeyuan Cheng, Makoto Tsubokura, Takuji Nakashima, Takahide Nouzawa, Yoshihiro Okada: A Numerical Analysis of Transient Flow past Road Vehicles Subjected to Pitching Oscillation, Journal of Wind Engineering & Industrial Aerodynamics, vol.99, pp.511-522 (2011).

7. Masaya Muto, Makoto Tsubokura, Nobuyuki Oshima: Negative Magnus Lift on a Rotating Sphere at around the Critical Reynolds Number, Physics of Fluids, vol.24, issue 1, 014102 (2012).

8. Seeyuan Cheng, Makoto Tsubokura, Takuji Nakashima, Takahide Nouzawa, Yoshihiro Okada: Numerical Quantification of Aerodynamic Damping on Pitching of Vehicle-Inspired Bluff Body, Journal of Fluids and Structures, vol.30, pp.188-204 (2012).

9. Tsubokura, M., Ikawa, Y., Okada, Y., Nakashima, T., Nouzawa, T.: Unsteady vehicle aerodynamics during a dynamic steering action: 2nd report, Numerical analysis, SAE International Journal of Passenger Cars – Mechanical Systems, 5(1), pp.395-411(2012).

10. Takuji Nakashima, Makoto Tsubokura, Mariano Vázquez, Herbert Owen, Yasuaki Doi: Coupled analysis of unsteady aerodynamics and vehicle motion of a road vehicle in windy conditions, Journal of Computers & Fluids, vol.80(10), pp.1-9 (2013).

11. Seeyuan Cheng, Makoto Tsubokura, Yoshihiro Okada, Takahide Nouzawa, Takuji Nakashima, and Deog Hee Doh: Aerodynamic Stability of Road Vehicles in Dynamic Pitching Motion, Journal of Wind Engineering and Industrial Aerodynamics, vol.122, pp.146-156(29 July 2013).

12. Yoshihiro Okada, Takahide Nouzawa, Makoto Tsubokura and Takuji Nakashima: Characteristics of unsteady flow around a vehicle affecting its high-speed stability during a dynamic steering action, Transactions of the JSME Series B, Vol.80,No.809, , DOI: 10.1299/transjsme.2014fe0009, pp.1-17(2014), (in Japanese).

13.Makoto Tsubokura, Andrew Hamilton Kerr, Keiji Onishi, Yoshimitsu Hashizume: Vehicle Aerodynamics Simulation for the Next Generation on the K-computer: Part 1 Development of the framework for fully unstructured grids up to 10 billion numerical elements, SAE International Journal of Passenger Cars – Mechanical Systems, 7(2): 2014-01-0621(2014).

14. Jing Li, Makoto Tsubokura, Masaya Tsunoda: Numerical Investigation of the flow around a golf ball at around the critical Reynolds number and its comparison with a smooth sphere, Flow, Turbulence and Combustion, vol.95, pp.415-436, doi: 10.1007/s10494-015-9630-4 (2015).

15.Keizo Yamamoto, Makoto Tsubokura, Jun Ikeda, Keiji Onishi, Sophie Baleriola: Effect of posture on the aerodynamic characteristics during take-off in ski jumping, Journal of Biomechanics, vol. 49, pp.3688-3696, DOI: 10.1016/j.jbiomech.2016.09.037 (2016).

16. Kousuke Nakasato, Makoto Tsubokura, Jun Ikeda, Keiji Onihsi, Shoya Ota, Hiroki Takase, Kei Akasaka, Hisashi Ihara, Munehiko Oshima, Toshihiro Araki: Coupled 6DoF Motion and Aerodynamic Crosswind Simulation Incorporating Driver Model, SAE International Journal of Passenger Cars – Mechanical Systems, 10(2): 2017-01-1525(2017) (SAE 2017 World Congress & Exhibition).

17. Jing Li, Makoto Tsubokura, Masaya Tsunoda: Numerical Investigation of the Flow past a Rotating Golf Ball and Its Comparision with a Rotating Smooth Sphere, Flow, Turbulence and Combustion, vol.99, pp.837-864, DOI: 10.1007/s10494-017-9859-1 (2017).

Success Stories


If you are interested in using FrontFlow/red-HPC, please contact:

Makoto Tsubokura, Team Leader

Complex Phenomena Unified Simulation Research Team

RIKEN Center for Computational Science

Tel: +81-78-940-5798