Mach Number Effect on Supersonic Drag Reduction using Repetitive Laser Energy Depositions over a Blunt Body

• Published in: TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES Vol. 60; no. 5; pp. 303 - 311
• Main Authors: IWAKAWA, Akira, SHODA, Tatsuro, MAJIMA, Ryosuke, PHAM, Son Hoang, SASOH, Akihiro
• Format: Journal Article
• Language: English
• Published: Tokyo THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES 01.01.2017; Japan Science and Technology Agency
• Subjects: Aerodynamics; Blunt bodies; Cylinders; Deformation; Deposition; Drag Reduction; Energy consumption; Energy Deposition; High Mach number; Mach number; Projects; Shock-waves; Supersonic drag; Trailers; Wind Tunnel Testing
• ISSN: 0549-3811; 2189-4205
• DOI: 10.2322/tjsass.60.303

Supersonic drag reduction performance using repetitive pulse energy depositions over blunt bodies was experimentally studied under two Mach numbers. The normalized drag reduction and energy deposition efficiency of Mach-1.92 over a 10-mm-dia. blunt-cylinder model were 8% and 1.2 at most, respectively. On the other hand, these values at Mach-3.20 over the same model were 22% and 6.2, respectively. The shock-wave deformation period using single-pulse energy deposition at Mach-3.20 was 64 μs. This duration was shorter than that of 80 μs at Mach-1.92, but the deformation magnitude on the model center axis of 40% at Mach-3.20 was larger than that of 15% at Mach-1.92. These experimental characteristics were consistent as solutions of the Riemann problem. Moreover, a drag reduction performance was much improved with a larger model diameter of 20 mm. Therefore, it has been experimentally demonstrated that the drag reduction performance due to energy deposition improves much at a high Mach number and with large model dimensions.