Experimental and Numerical Investigation of Active Control of Inlet Ducts

Abstract

The effect of steady and unsteady control jets on the performance of a very aggressive (length to exit diameter ratio, L/D, of 1.5) inlet duct was investigated. Experiments were performed for a range of inlet Mach numbers from 0.2 to 0.45 and compared with numerical simulations for the baseline flow case at an inlet Mach number of 0.45. A brand new facility was designed and built to enable various actuation methodologies as well as multiple measurement techniques. In the present work, a pair of control jets was placed in streamwise locations where flow was expected to separate. Steady and unsteady static pressure measurements, along the upper and lower walls of the duct, were performed for various combinations of actuation. The parameters that were tested include the control jets momentum coefficient, the blowing ratio, the actuation frequency, as well as different combinations of jets. It was shown that using mass flux ratio as a criterion to define flow control is inappropriate, and one needs to provide...