Ramjet diffuser flowfield response to large-amplitude combustor pressure oscillations

Abstract

The unsteady flow of a two-dimensional ramjet diffuser is studied numerically by solving the Navier-Stokes equation with a two-equation turbulence model. Unsteadiness is introduced by prescribing a pressure disturbance at the diffuser exit plane. The case with a sinusoidal exit plane pressure flucutation of 20% of the mean exit pressure is considered to simulate pressure oscillation from a ramjet combustor. The resulting flowfield exhibits a complicated interaction between the terminal shock, separation pocket, and inviscid core flow. The exit plane flow properties feature a nonlinear response to the imposed sinusoidal pressure variation.