On determining the wave characteristics of controlled disturbances in the boundary layer under the action of a pair of weak shock waves
Yu.G. Yermolaev, A.D. Kosinov, L.V. Afanas’ev, M.V. Piterimova
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
Keywords: supersonic flow, experimental studies, flat plate, controlled disturbances, N-wave, wake, subharmonic resonance
Abstract
The paper describes experimental results on the action of weak shock waves on the development of controlled disturbances in a supersonic boundary layer on a flat plate at the Mach number of 2.0, which are obtained by measurements performed by a constant-temperature hot-wire anemometer. A two-dimensional surface roughness element 150×7×0.13 mm in size, mounted on the side wall of the test section of the T-325 wind tunnel based at ITAM SB RAS, generated a pair of weak shock waves in the free stream. Controlled disturbances are inserted into the flow by a high-frequency glow discharge in a chamber inside the model. Owing to interaction of the pair of weak shock waves with the leading edge of the flat plate, a steady wake is formed in the boundary layer, where the evolution of controlled disturbances occurs. A weakly nonlinear regime of evolution of controlled disturbances is studied under the conditions of a homogeneous boundary layer on the flat plate and a boundary layer distorted by the wake. The wave characteristics of disturbances are analyzed. A new method of estimating the dispersion relation is proposed. The experimental data are compared with the numerical results. Numerical simulations are performed based on the liner stability theory under the conditions of a homogeneous boundary layer.
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