Numerical Simulation of Axisymmetric Supersonic Screech Tones

Abstract

Despite the advances in screech research during the past few decades, it is still a challenge task to predict the screech amplitude and to understand the underlying nonlinear mechanism in detail. In this paper an axisymmetric computational aeroacoustic procedure is developed to predict the axisymmetric supersonic screech tones. The axisymmetric Navier-Stokes equations and the two equations standard k turbulence model modied by Turpin & Troyes are solved in the generalized curvilinear coordinate system. A generalized wall function is applied in the nozzle exit wall region. The dispersion-relation-preserving scheme is applied for space discretization. The 2N storage low-dissipation and low-dispersion Runge-Kutta scheme is employed for time integration. Much attention is paid to far eld boundary conditions and turbulence model. The underexpanded axisymmetric supersonic jet screech tones are simulated over the Mach number from 1.05 to 1.2. Numerical results are presented and compared with the experimental data by other researchers. It is demonstrated that the axisymmetric jet screech tones can be simulated correctly and the modes jumping can be captured. The receptivity process is presented in a screech cycle, and the mechanism of instability waves generation is analyzed. Finally, the phenomena of shock motions are analyzed, and its relationship with the screech tones is discussed.