Detached eddy simulations of the side-loads in an overexpanded nozzle flow

In this paper, we numerically examine the separated flow in an overexpanded nozzle developed during the starting phase of a rocket engine featuring the side-load effect. We use detached eddy simulation (DES), namely, its version referred to as delayed DES, and compare our results with the existing experimental and numerical data. The calculations are based on finite volume approximation of the Navier–Stokes equations for perfect gas and pressure-based formulation with PISO coupling. By investigating the unsteadiness associated with the shock-induced separation, a better insight can be obtained as to how these affect the nozzle start-up. Three-dimensional, transient, turbulent computational fluid dynamics methodology has been demonstrated to capture major side-load physics with supersonic nozzles. The main flow properties (wall pressure levels, shock waves pattern, side load locus) are rather well reproduced. We suggest using a delayed detached eddy simulation for more accurate predictions of the flow separation.