Assessing IDDES-Based Wall-Modeled Large-Eddy Simulation (WMLES) for Separated Flows with Heat Transfer

Rozie Zangeneh

doi:10.3390/fluids6070246

Abstract

The Wall-modeled Large-eddy Simulation (WMLES) methods are commonly accompanied with an underprediction of the skin friction and a deviation of the velocity profile. The widely-used Improved Delayed Detached Eddy Simulation (IDDES) method is suggested to improve the prediction of the mean skin friction when it acts as WMLES, as claimed by the original authors. However, the model tested only on flow configurations with no heat transfer. This study takes a systematic approach to assess the performance of the IDDES model for separated flows with heat transfer. Separated flows on an isothermal wall and walls with mild and intense heat fluxes are considered. For the case of the wall with heat flux, the skin friction and Stanton number are underpredicted by the IDDES model however, the underprediction is less significant for the isothermal wall case. The simulations of the cases with intense wall heat transfer reveal an interesting dependence on the heat flux level supplied; as the heat flux increases, the IDDES model declines to predict the accurate skin friction.

Highlights

Wall-bounded turbulent flows play a key role in industrial applications in addition to their importance in relatively simple configurations for academic research
This study is conducted to assess the performance of the Improved Delayed Detached Eddy Simulation (IDDES) model acting as a Wall-modeled Large-eddy Simulation (WMLES) in separated flows with heat transfer
The results obtained by the IDDES model with respect to the reattachment lengths, C f and Stanton number distributions, fluid flow, and thermal fields follow the reference experiment and reference LES results closely

Summary

Introduction

Wall-bounded turbulent flows play a key role in industrial applications in addition to their importance in relatively simple configurations for academic research. Simulation (LES), in which all of the large energetic scales throughout the boundary layer need to be resolved. This could lead to serious challenges of modeling when flow separation, drag, or heat transfer are of interest [3]. In WMLES, the large-scale unsteady, energetic turbulent configurations in the outer region of the boundary layer are resolved, meaning structures with low energy and universal behavior to be modeled. This enables a competitive computational cost compared with other high fidelity approaches

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