UNSTEADY AND QUASI-STEADY MODES OF THE FLOW OVER AN INTAKE TESTED IN A HOTSHOT WIND TUNNEL

Results of a numerical simulation of an unsteady flow in an axisymmetric intake with internal compression tested in a hotshot wind tunnel with a fixed-volume settling chamber are discussed. The present simulations reveal the main features of various modes: unsteady processes of wind tunnel and intake starting, quasi-steady flow over the started intake with a supersonic flow velocity in the intake duct, and subsequent ulterior transition to the flow with a detached bow shock wave in front of the air intake with a subsonic flow velocity in the duct. A previously unknown mode of the flow over the intake with oscillating motion of the bow shock wave is observed. It is shown that oscillations decay with time, and the bow shock wave position in the incoming flow becomes stabilized at a certain distance from the leading edge of the intake with the test flow in the wind tunnel being preserved.