JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EDA201C21

Subject Category: Aeronautical Technology

PDF (to be added)

• Responsible Representative: Kanako Yasue, Aviation Technology Directorate, team leader, Aviation Integration Innovation Hub, Airmobility Design Team
• Contact Information: Keita Kimura, Japan Aerospace Exploration Agency, Aviation Technology Directrate(kimura.keita@jaxa.jp)
• Members: Fumihiro Kajiwara, Yuki Kishi, Keita Kimura, Hideaki Sugawara, Yasutada Tanabe

Abstract

To advance the design technologies for future rotorcraft, including helicopters and eVTOL vehicles, this study has focused on airfoil design and associated analyses in the current fiscal year. The objective is to develop airfoils that minimize power consumption across various flight conditions, such as hovering, forward flight, and descent. To this end, optimal airfoil design is pursued by combining two-dimensional CFD analyses of airfoil sections with optimization algorithms.

As a preliminary step toward the optimization process, a tool has been developed to generate aerodynamic tables, which compile lift, drag, and moment coefficients over a range of Mach numbers and angles of attack. In rotorcraft applications, airfoils are subjected to a wide range of operating conditions in terms of both Mach number and angle of attack. Therefore, evaluations under limited conditions are often insufficient. By organizing the results into aerodynamic tables, the data can be more effectively utilized and fed back to the design process.

This report presents representative examples of two-dimensional airfoil analyses.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

In airfoil performance analyses for rotorcraft design, aerodynamic data over a wide range of Mach numbers and angles of attack are required, resulting in a large number of computational cases. For reference, approximately 200 cases are needed to generate a single aerodynamic table in this study. Considering that multiple airfoil configurations will be evaluated in future work, the use of high-performance computing (HPC) is indispensable.

Achievements of the Year

Figure 1 shows an overview of the computational grid used in this study. The grid system consists of an overset grid combining an O-type grid around the airfoil with a background grid. By rotating the O-type grid, arbitrary angles of attack can be imposed, while the freestream conditions are adjusted to achieve the desired Mach number and inflow conditions. In this study, a NACA 23012 airfoil with a tab is used as a representative example.

Figure 2 presents examples of CFD results, showing pressure contour distributions at M = 0.5 and angles of attack alpha = −10, 0, and 10deg. The aerodynamic performance coefficients are automatically computed from the time-averaged distributions of pressure and wall shear stress for each condition.

Figure 3 shows a visualization example of the aerodynamic table (in .C81 format) compiled from all CFD cases, presented as a plot of angle of attack versus lift-to-drag ratio. It can be observed that the angle of attack corresponding to the peak performance shifts with Mach number, and that the aerodynamic performance significantly deteriorates, particularly for Mach numbers above approximately M=0.6.

Fig.1: Overview of the 2D-CFD Grid (O-type Grid Around the Airfoil with Background Grid)

Fig.2: Pressure Contour Distribution (Mach = 0.5, NACA 23012 with Tab)

Fig.3: Example of Aerodynamic Table Visualization (AoA vs. L/D)

Publications

- Oral Presentations

Yuki, KISHI, Keita KIMURA, "Multi-Objective Optimization of Blade Airfoil for Utility Helicopter Using Modified PARSEC Representation", 63rd Aircraft Symposium, 1F09, 2025

Usage of JSS

Computational Information

• Process Parallelization Methods: N/A
• Thread Parallelization Methods: OpenMP
• Number of Processes: 1
• Elapsed Time per Case: 2 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.28

Details

Please refer to System Configuration of JSS3 for the system configuration and major specifications of JSS3.

*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.

ISV Software Licenses Used

*2: Fraction of Usage：Percentage of usage relative to each resource used in one year.

JAXA Supercomputer System Annual Report February 2025-January 2026