Control of Pressure Loads in Complex Cavity Configurations

The need to reduce the fluctuating surface pressure loads in realistic three dimensional cavity configurations is clear for many applications. Here an experimental study was conducted to examine the effects of different leading edge blowing concepts for a highly three dimensional cavity. In addition to the suppression studies the properties of the complex cavity was studied through the use of several simpler cavities with limited features of the full three dimensional cavity. The two leading edge blowing suppression concepts examined were micro jets and segmented slots. Both of the concepts showed significant reductions in the fluctuating surface pressures with modest amounts of mass flowing through the injectors. The reductions observed in the fluctuating surface pressure levels resulted from decreases in both the broad band and resonant features of the surface pressures. Velocity field measurements showed that the controlled cavities had significantly reduced fluctuating velocities in the shear layer and a smaller amplitude reverse flow along the bottom of the cavity. The observations reported in this study have also served as a basis for designing actuators for larger scale tests where consistent results were found.