Investigation of Turbulent Wake-Boundary Layer Interaction With Injection

Abstract

The present paper is concerned with experimental study of the interaction between a wake, with injection at its begining,and a boundary layer. The wake is developed downstream a finite length and thickness plate inside an open-type wind tunnel test section while the boundary layer is developed over the wall of the test section. The measurements are carried out at Reynolds number 1.8 x 105 and injection to Main stream velocity ratios (A) of (0 < A< 0.7). In the experiments the mean velocity profiles, the wall static pressure distrubtion and the local skin friction coefficient are measured. The results indicate that, for a certain velocity ratio, moving downstream from the trailing edge of the thick plate the wake decays while the boundarey layer grows gradually. Also, the wake depth decreases,the wake width increases and the position of maximum velocity moves into the inner layer. On the other hand-at a certain distance from the trailing edge-as the velocity ratio increases the wall pressure coefficient, the momentum thickness Reynolds number and the shape factor decrease while the skin friction coefficient increases. Also-as the velocity ratio increases the rate of wake decay, the wake center line velocity and the wake width increase while the wake depth decreases.