Instability of Astrophysical Jets. II : Numerical Simulation of Two-Dimensional Choked Underexpanded Slab Jets : Astrophysics and Relativity

概要

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Lateral oscillations of choked underexpanded rectangular jets with a large aspect rario are observed experimentally. We compare the experiments with the results of our numerical simulations of two-dimensional slab jets. A time-dependent technique of solution is applied to solve the Euler equations for a compressible ideal gas. The numerical results show that the jet does not oscillate laterally when the symmetric boundary condition is applied. On the other hand, the self-sustained asymmetric oscillation of the jet occurs under the asymmetric boundary condition. When an asymmetric jet oscillation appears in the computed domain, it continues even after the asymmetric boundary condition was replaced by the symmetrical ones. The oscillation of the supersonic jet is self-sustained. This is probably because of the feedback loop consisting of the sound waves propagating towards the nozzle exit and the coherent structures convected with jets.
理論物理学刊行会の論文
1990-11-25