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6.13.16 Asai/Ambo

Title: “Advanced Experimental Techniques for Dynamic Wind-Tunnel Testing”

Speakers: Keisuke Asai, Tohoku University, Sendai Japan

Takumi Ambo, PhD Candidate, Tohoku University, Sendai Japan

Date: June 13, 2016

Time: 10:00am

Location: NIA, Room 101

Abstract: (Dr. Asai Presentation) Recent research activities on advanced measurement techniques at Tohoku University are overviewed with a particular emphasis on applications of pressure-sensitive paint (PSP) to unsteady and dynamic wind-tunnel testing. The effects of properties of paint film on the time response of PSP are discussed and some new unsteady PSP formulations are introduced; one is an ultra-fast PSP coating with sub-micro second time response and the other is a sprayable PSP with low flow intrusiveness. Applications of these paints include interaction between a traveling shock wave and an obstacle, flow behind a square cylinder, unsteady flow induced by an active flow control device, and transonic buffeting on a transport wing. Studies on new experimental techniques in dynamic wind tunnels are also present such as the six degree-of-freedom robotic manipulator and the Magnetic Suspension and Balance System (MSBS). The capabilities of various measurement techniques applied to a moving model are reviewed.

Bio: Keisuke ASAI is a Professor of Aerospace Engineering at Tohoku University in Japan. He received a bachelor degree in Aeronautical Engineering from Kyoto University in 1980 and a Ph.D. degree in Aeronautics and Astronautics from University of Tokyo in 1995. He was a research scientist at National Aerospace Laboratory of Japan from 1980 to 2003. During 1988-1989 for one year, he was a Visiting Researcher in Experimental Techniques Branch, Transonic Aerodynamics Division at NASA Langley Research Center. From 1999-2003, he managed Techno-Infrastructure Program called “MOSAIC” that is an interdisciplinary research project with chemists and material scientists to develop molecular sensor technology for aerodynamic measurements. He is the recipient of the 1998 AIAA Aerodynamics Measurement Technology Best Paper Award, the 2002 AIAA Outstanding Paper Award, the 2003 JSASS Technical Award, the 2016 Science and Technology Award, MEXT, Japanese Government, etc. He is Associate Fellow of the AIAA and Fellow of the JSASS. He has published over 70 papers in the archival literature on experimental aerodynamics.

Investigation rear-end of flow structures on a 6:1 prolate spheroid by using the magnetic suspension and balance system

Abstract: (Mr. Ambo Presentation) To study the flow separation at the rear end of a 6:1 prolate spheroid, oil flow visualization were conducted on a model in free levitation using the 0.3-m Magnetic Suspension and Balance System. Reynolds number based on the model length was 0.5 million and the angle of attack of the model was set at 0 and 5 degrees. Complicated laminar separation patterns were observed at the rear end of the model even at zero angle of attack. To evaluate the influence of support interference, a systematic experiment was conducted with small excrescences simulating disturbance of a support system. The obtained results indicate that the excrescence has a significant influence on the separation patterns, even when its diameter is as small as 0.5 mm. The separation was delayed in the downstream of the excrescence, suggesting that the change of separation pattern is caused by the transition of laminar boundary layer behind the excrescence.

Additional Info: Keisuke Asai is co-Director of the Experimental Aerodynamics Laboratory within the Department of Aerospace Engineering at Tohoku University; Takumi Ambo is a PhD student. The laboratory focuses on the development of instrumentation and test techniques applicable to unsteady flows. This includes molecular imaging techniques for flow field visualization such as Pressure and Temperature Sensitive Paints (PSP/TSP), or Global Luminescent Oil Films (GLOF), dynamic wind tunnel testing using Magnetic Suspension and Balance Systems (MSBS) as well as multi-degree-of-freedom robots, and finally simulation of flight on Mars using the Mars Wind Tunnel.



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