Characteristics of transonic rectangular cavity flows

Experiments are performed to study the characteristics of rectangular cavity flows. Mean and fluctuating surface pressure in a Mach-1.28 turbulent flow past rectangular cavities are obtained. The cavity length-to-depth ratio L/D varies from 2.43 to 43.00, and the length-to-width ratio L/W is 0.5, 1.0, and 2.0. The effect of cavity depth is studied, in which L/W or both L/D and L/W are held constant. The results indicate that L/D is the most important parameter in determining the characteristics inside the cavity and in its vicinity. The effect of L/W is significant only at the aft half of the cavity. Lower static pressure aft of the front face and higher static pressure at the aft half of the cavity are observed with decreasing depth-to-incoming boundary-layer thickness D/δ₀ at constant L/W. At constant L/D and L/W, the results show an opposite trend. The amplitude of surface pressure fluctuation decreases at larger L/D. The parameter L/W mainly affects the peak surface pressure fluctuation ahead of the rear face.