Detached eddy simulation of unsteady flow over a frontal cavity

Abstract

Frontal cavity consists of complex unsteadiness which causes bow shock instabilities when the body is moving at supersonic or hypersonic speed through a fluid. These complex unsteady flow fields are an important practical concern in the aerospace applications. Understanding this flow field around the frontal cavity will help us to know more in depth about these instabilities to create effective control methods to avoid structural damages. The main objective of the present research is to analyze the bow shock instabilities at different Mach number around the frontal cavity at supersonic and hypersonic speeds by using the numerical concept of Detached Eddy Simulations (DES) in two dimensional axisymmetric domain. Three different freestream Mach numbers (2, 4 and 6) were considered in the present investigation in order to study the effect of Mach number on flow unsteadiness. It was observed that an increase in Mach number, the frequency of most dominant mode (bow shock pulsation) increases significantly. In addition to that, additional low amplitude sub-dominant modes were observed for all the cases of freestream Mach numbers studied in the present investigation.