To study the influence characteristics of downstream wave systems on shock wave/boundary layer interference (SWBLI) in hypersonic inlet, a model was designed which can generate a stable first shock wave by a linear com-pression ramp, and can simulate the change of the downstream wave system by changing the shape of the adjusta-ble compression ramp downstream of the first shock wave. The relation between different shapes of adjustable compression ramp and SWBLI generated by the first shock wave on the upper wall is studied. The simulation re-sults show that the downstream adjustable compression ramp has a significant impact on the SWBLI. Significant SWBLI is observed when the compression ramp is adjusted to be linear or convex. While by adjusting the compres-sion ramp to be concave, the area of the up-stream separation region can be effectively reduced or even eliminated. The results show that the upstream SWBLI can be influenced by the downstream wave system, and can be mini-mized or eliminated by adjusting the wave system.
Since the current conventional straight isolator cannot meet the needs of various new engines, the annular isolator has become a hot research object. At present, there are few studies on the flow field in the annular isolator, and most of the research contents are aimed at the shock train leading edge in the annular isolator, and there are relatively few studies on the motion of the shock train in the annular isolator. Therefore, this paper conducts experiments on the annular isolator under the steady-state back pressure to explore the motion characteristics of the shock train in the annular isolator. An experimental device of the annular isolator under static wind tunnel is designed, and the wall pressure datas of the annular isolator under different steady-state back pressures are collected. The experimental results show that the oscillation of the shock train leading edge in the annular isolator is a low frequency oscillation, and the shock train has a hysteresis effect during the movement.
To realize the quasi-quantitative Schlieren measurement of the shock train structure across the cylindrical isolator in the supersonic flow field, based on the theory of Schlieren measurement and light transmission, we propose the design scheme of conformal windows and discuss the machining feasibility with the window’s parameters. The relationship between the Schlieren imaging effect, the deflection of parallel light in the Schlieren apparatus, and the conformal optical window aberrations was researched, putting forward the optical simulation model of the conformal optical windows and the quasi-quantitative Schlieren measurement. Moreover, considering the actual wind tunnel test conditions, under the speed of Mach 2 at the isolator’s inlet, the distortion brought by conformal optical windows in the Schlieren observation region was simulated by the computational fluid dynamics method. Finally, the image correction algorithm for the distorted picture caused by the conformal windows was presented, and the quasi-quantitative Schlieren measurement through the conformal optical window pair was conducted for the experimental verification. The results reveal the quasi-quantitative Schlieren measurement effect across the high-precision conformal optical window pair of the cylindrical isolator, providing guidance on maintaining the balance between the manufacturing feasibility and the observation performance of conformal windows.
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