Compressibility Effects for Turbulence Models at Supersonic and Hypersonic Flow Regimes. Consistency and Implementation of Mathematical Models versus Flow Physics of Strongly Separated Flows.

摘要

Fluid compressibility can remarkably modify the behavior ofrnturbulent flow with respect to the incompressible case. The presence ofrnstrong pressure induced density changes adds to the turbulencernphenomenology new specific processes and mechanisms, such as newrnpathways for energy exchanges, a strong coupling between momentum andrnenergy exchanges, etc., significantly altering the flow behavior. Manyrnresearch groups are working on methods of including these compressibilityrneffects in conventional turbulence models to predict more realistically thernflow-field for compressible conditions. The aim of this work is thernverification, validation and further implementation of relevantrncompressible corrections to the Navier-Stokes IAI in-house code NESrnwithin the "baseline" Spalart-Allmaras turbulence model. Two differentrntype of flow have been investigated to assess the differences between therncompressibility correction models that have been implemented within NES.rnWe first address the base pressure enhancement for supersonic afterbodyrncomputations. Afterwards the second type of flow deals with shockrnturbulent boundary layer interaction at the junction of a cone flarernconfiguration. The analysis of the numerical results and their comparisonrnwith the experimental data show that in most cases the proposed correctionrnproduces a significant improvement of the numerical predictions.