A joint computational fluid dynamics and experimental fluid dynamics program

Abstract

The Air Force Research Laboratory Air Vehicles Directorate (AFRL/VA) initiated a joint Computational Fluid Dynamics/Experimental Fluid Dynamics (CFD/EFD) test program to investigate and analyze the flow field of a lambda wing-body aerodynamic configuration. The test program involves a multitude of cross-functional specialties, ranging from experimental testing to computational resources to state-of-the-art material manufacturing techniques. A preliminary computational grid and subsequent analysis was performed to provide estimated loads and moments necessary for proper manufacturing of a wind tunnel model. The test program used rapid prototyping manufacturing techniques to fabricate a model for ground testing; implemented innovative, non-intrusive measurement techniques in ground test; and compared CFD with experimental data acquired from ground tests. The measurement techniques employed include standard force and moment measurements as well as global optical diagnostic techniques such as intensity- and lifetime-based pressure sensitive paint, projection Moire interferometry, and Doppler global velocimetry. The results obtained from these various measurement techniques will be used for comparison with CFD results. To achieve better correlation between the wind tunnel results and the CFD results, the computational grids will include the wind tunnel structure and appropriate mounting hardware. A comparison of the results from this "virtual" wind tunnel will be made to the results from the actual wind tunnel. Computational results include a variation of multiple trailing-edge flap configurations, angles of attack, and freestream Mach number conditions achievable in the subsonic aerodynamic research laboratory. AFRL researchers acquired a better understanding of the multiple disciplines: rapid prototyping, various measurement techniques, and CFD. It can be concluded that increased communication and comparison between experimental and computational fluid diagnostics was achieved successfully. Joint CFD and EFD test programs will continue to be developed and improved.