Variation of Flow Control Configurations to Improve Submerged Inlet Uniformity

A flow control study was initiated upon a generic submerged inlet to determine whether discrete blowing could be effective in eliminating the boundary layer deficit created in the throat and therefore the engine face. The throat was a rectangular area of 7.14 cm2, with the stream wise velocity of Mach 0.064, with a free stream velocity of Mach 0.039. Different mass flow rates were applied to determine the quantity necessary to overcome the effect of the boundary layer upon the inlet. Up to seven percent of the inlet mass flow was injected to determine the mr necessary to overcome the boundary layer and wall spillage induced vortices. Discrete holes were injected at the head of the ramp in a manner in which the flow was angled to follow the ramp. The holes directed the flow parallel to the ramp and in another configuration with a induced secondary angle to direct the flow towards the sidewalls. The hole locations were also altered to be approximately one third of the way down the ramp, closer to the inlet. This was found to decrease the effective amount of blowing required by a small amount, since the boundary layer was being disrupted and reset at this location. The growth would be less after the sluggish region had been energized and this should be reflected in the inlet profile uniformity. Three-component laser Doppler velocimetry (LDV) was the investigative tool utilized in this test to determine the changes created by blowing upon the secondary velocity components and the origin of any improvements in the throat profile. The downstream location, with the addition of the angled flow towards the wall, provided the best results cutting the amount of mass addition required by two percent into the inlet to obtain the same results. Nomenclature u/uavNormalized Streamwise (x-direction) velocity component v/uavNormalized Y-direction velocity component w/uavNormalized Z-direction velocity component u′v′/u2avNormalized uv cross component of the Reynolds stress ui Laser doppler velocimetry measurement components mr The mass flow ratio of the flow control to that measured for the inlet uav Average measured throat velocit