Supersonic Wind Tunnel Tests of Wavy-Walled Cylinders
[Technical Report, Final Report]
AEROSPACE RESEARCH LABS WRIGHT-PATTERSON AFB OH
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The primary objective of the experiment was to provide pressure measurements for use in flutter calculations. Wavy-walled cylinders were wind tunnel tested at Mach 3.0 and 4.62. The walls of the cylinders were rigid, with a sinusoidal deflection pattern machined in the outer surface. The waves extended in both the axial and circumferential direction. Flow was directed along the cylinder axis. Static pressures were measured at the wavy surface of each cylinder. The pressure perturbations proved to be smaller in amplitude than predicted by inviscid aerodynamic theories. The pressure distribution also had a small phase shift downstream. The tests are helpful in studying viscous flow effects on the pressures. A direct comparison with an existing idealized boundary layer theory was impossible, however, because of the choice of wave height on the model. Boundary layer separation occurred under some conditions. Separation was observed in the form of a small bubble lying behind a wave, particularly in regions where the boundary layer was laminar. Oil film studies were made by using a thin film of oil on the surface. When exposed to ultraviolet light, the oil film fluoresced, revealing the stream line pattern. Photographs of the oil film patterns and a number of Schlieren pictures are presented.
- Fluid Mechanics