JAXA Supercomputer System Annual Report April 2018-March 2019

Report Number: R18ETET04

Subject Category: Skills Acquisition System

PDF available here

• 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 the aerodynamic characteristics of a coaxial rotor.

Reference URL

Please refer to ‘Future type rotary-airfoil airplane system technology | Sky Frontier – Sky Frontier Program | Aeronautical Technology Directorate‘.

Reasons for using JSS2

This study needed the computational high performance with the rotorcraft analysis code rFlow3d which was developed by JAXA.

Achievements of the Year

We performed CFD analysis with the rFlow3D where the computational mesh of the rotor and wing are shown in Fig.1. Fig.2 shows the interference of the rotor downwash on the wing at advance ratio 0.3. Strong interference of 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.

Fig.1: Computational Mesh of Rotor and Wing

Fig.2: Vertical Velocity Distribution around Rotor and Wing in Side View : Advance Ratio = 0.3

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. Blade Vortex 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. (in Japanese)

2) Ryo Hayakawa, Takeshi Akasaka, and Yasutada Tanabe, Numerical Study of Rotor/Wing Interaction on a Compound Helicopter in High Advance Ratio, 56th JSASS Aircraft Symposium, Yamagata Telsa, November 14-16, 2018, Paper No. JSASS-2018-5167. (in Japanese)

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

Please refer to System Configuration of JSS2 for the system configuration and major specifications of JSS2.

*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 2018-March 2019