摘要: In the present study, a supersonic cavity flow is actively controlled using high-frequency flapping jets. A two-dimensional rectangular cavity with a ratio L/D = 5.0 of the cavity length L, 50 mm, to the depth D, 10 mm, is used as... 展开 In the present study, a supersonic cavity flow is actively controlled using high-frequency flapping jets. A two-dimensional rectangular cavity with a ratio L/D = 5.0 of the cavity length L, 50 mm, to the depth D, 10 mm, is used as a test model. The Mach number of the freestream is M = 1.9, and the cavity flow without any flow control oscillates at the frequencies of the dominant "Rossiter modes" ranging between 2 kHz and 15 kHz. The flapping frequency of the jets is adjusted to vary in between approximately 15 kHz - 22 kHz. The effect of the jet discharging location is investigated by setting the location at the leading edge (LE), bottom-wall upstream side (BU), bottom-wall downstream side (BD), and trailing edge (TE). The effects of jet injection are evaluated from the power spectral densities (PSD) of the bottom wall pressure oscillations and contrast fluctuations in the time-sequential schlieren images. The velocity fields are also investigated through the non-time-resolved Particle Image Velocimetry (PIV) measurements. The jet discharging from TE and BU enhanced the turbulent intensity inside the shear layer and the cavity. The reverse flow in the vicinity of the bottom wall of the cavity was enhanced in the case of LE, although the reverse flow inside the cavity was weaken in the case of the BU. The flow field in the case of BU shows the possibility that the flow field type was transformed from the open cavity to closeed cavity. The (PSD) of the bottom wall pressure oscillations were decreased in the case of BD, although there were no significant changes on the PSD in the case of TE. The effects of flapping oscillation were also evaluated by comparing the results of steady jet discharge cases with the same discharge locations. The effects of flapping oscillation are minor than those of the locations. The growth rate of the shear layer was found to be different depending on whether it was oscillating or not. 收起