Experimental study on the influence of angle of attack and unit Reynolds number on the transition of the hypersonic boundary layer of the HyTRV lifting body
Abstract
<p indent="0mm">To achieve a higher lift-to-drag ratio, aircraft under real flight conditions typically fly with an angle of attack. Changes in angle of attack cause variations in surface pressure gradients, significantly affecting the boundary layer transition of the aircraft. This study focused on the model of the HyTRV hypersonic flying body configuration. Experimental measurements of the boundary layer of the HyTRV model at different angles of attack were conducted in a Mach 6 Ludwieg tube wind tunnel using high-frequency pressure sensors (PCB) and high-speed infrared cameras. The study analyzed the instability characteristics of the flow vortex region at the abdomen, the transverse flow region at the waist, and the flow vortex region at the shoulders of the HyTRV. The experimental results indicate that the transition position of the flow vortex region at the abdomen changes little with increasing angle of attack. This stability is primarily due to alterations in the transition mechanism at that location as the angle of attack increases. On the windward side of the HyTRV model, the originally independent transition zones undergo movement, merging, and expansion with increasing angle of attack. This phenomenon causes changes in the dominant transition modes of the transverse flow region at the waist and the flow vortex region at the shoulders. Specifically, the dominant mode in the transverse flow region at the waist shifts from the secondary instability mode of transverse flow to the second mode, while the dominant mode in the flow vortex region at the shoulders shifts from the flow vortex mode to the secondary instability mode of transverse flow.</p>
