DAHWIN: Digital/Analog-Hybrid Wind Tunnel

The development of ‘Digital/Analog-Hybrid WINd tunnel (DAHWIN),’ which is an innovative system integrating CFD (Computational Fluid Dynamics) with EFD (Experimental Fluid Dynamics), is presented. The aim of the system is to improve efficiency, accuracy, and reliability of aerodynamic characteristics evaluation in aerospace vehicle developments through mutual support between EFD and CFD. DAHWIN is constructed based on two large facilities, JAXA 2m x 2m Transonic Wind Tunnel for EFD and JAXA Supercomputer System for CFD. The function of this system consists of optimization of test planning, an accurate correction of the wind tunnel wall and support interaction effects, the most probable aerodynamic characteristics estimation based on both EFD and CFD data, and so forth. Key technical challenges in the system development, such as an automatic grid generator, high-speed CFD solver, and a high-speed data processing technique for image measurement data, are addressed. Some preliminary applications of DAHWIN to practical wind tunnel tests showed the usefulness and reliability of DAHWIN.