Spatial-Temporal Instability of an Inviscid Shear Layer

Spatial-Temporal Instability of an Inviscid Shear Layer

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In this work, we explore the NEFF I38KHV2S0 N90 Built In 37cm 3 Speeds Island Cooker Hood Black transition of absolute instability and convective instability in a compressible inviscid shear layer, through a linear spatial-temporal instability analysis.From linearized governing equations of the shear layer and the ideal-gas equation of state, the dispersion relation for the pressure perturbation was obtained.The eigenvalue problem for the evolution of two-dimensional perturbation was solved by means of shooting method.The zero group velocity is obtained by a saddle point method.The absolute/convective instability characteristics of the flow are determined by the temporal growth rate at the saddle point.

The absolute/convective nature of the flow instability has strong dependence on the values of the temperature ratio, the velocity ratio, the oblique angle, and M number.A parametric FLOR-ESSENCE study indicates that, for a great value of velocity ratio, the inviscid shear layer can transit to absolute instability.The increase of temperature ratio decreases the absolute growth rate when the temperature ratio is large; the effect of temperature ratio is opposite when the temperature ratio is relatively small.The obliquity of the perturbations would cause the increase of the absolute growth rate.The effect of M number is different when the oblique angle is great and small.

Besides, the absolute instability boundary is found in the velocity ratio, temperature ratio, and M number space.