On the Control of Turbulent Axisymmetric Separating/Reattaching Flows Using Zonal Detached Eddy Simulation

Abstract

The present work focuses on the numerical simulation of a turbulent tridimensional axisymmetric step controlled by means of continuous jets. The dynamics of this configuration with a Mach number M∞ =0 .7 leading to a Reynolds number based on the largest diameter which is equal to 1.2 × 10 6 has already been thoroughly investigated in previous studies. Thus, the main objective is here to analyse the influence of two controlled devices acting in different regions of the separated flows, i.e. in the shear layer or in the recirculation area. The final purpose consists in controlling side loads occurring on the massively separated afterbody due to intense pressure fluctuations. For both controlled configurations, instantaneous, statistical and fluctuating properties are scrutinized. Especially, a two-point spectral analysis is performed on the entire wall of interest of the afterbody. This last investigation permits to understand the influence of the control on the mechanisms related to the dimensionless frequency StD =0 .2 and its associated antisymmetric mode m =1 .I t also provides an explanation for the different efficiencies obtained.