Numerical Investigation of Flow Structures Around a Cylindrical Afterbody Under Supersonic Condition

TL;DR

This study uses Large Eddy Simulation with the dynamic Smagorinsky model to analyze complex flow structures around a cylindrical afterbody at Mach 2.46, comparing results with experiments and other models to evaluate turbulence prediction accuracy.

Contribution

It demonstrates the effectiveness of LES over k-epsilon models in predicting flow properties and turbulence structures in supersonic cylindrical wake flows.

Findings

LES accurately predicts flow in recirculation regions

LES results agree better with experiments than k-epsilon model

POD analysis reveals dominant energetic flow structures

Abstract

Large Eddy Simulation (LES) with dynamic Smagorinsky model has been applied to numerically investigate the complicated flow structures that evolve in the near wake of a cylindrical after body aligned with a uniform Mach 2.46 flow. Mean flow field properties obtained from numerical simulations, such as axial velocity, pressure on base surface, have been compared with the experimental measurements as well as with other published results. It has been found that standard k-epsilon model fails to predict the flow properties in the recirculation region where better agreement has been observed between the data obtained from LES and experimental measurements. Flow Statistics like turbulent kinetic energy and primary Reynolds stress have also been calculated and compared with the results obtained from experiments in order to quantitatively assess the ability of LES technique to predict the turbulence properties of flow field in the highly compressible shear layer region. The data obtained from LES has been further analyzed to understand the evolution of coherent structures in the flow field. Proper Orthogonal Decomposition (POD) of the data obtained from central plane in the wake region has been performed in order to reveal the most energetic structures present in the flow field.