Extension of an amplification factor transport transitional approach with a reynolds stress model

Fernandez, Jose M.Garro, Angland, David and Hu, Zhiwei (2020) Extension of an amplification factor transport transitional approach with a reynolds stress model. In AIAA AVIATION 2020 FORUM. vol. 1 PartF, American Institute of Aeronautics and Astronautics.. (doi:10.2514/6.2020-2979).

Abstract

An extension of the amplification factor transport (AFT) transitional approach is presented with a SSG-LRR-ω Reynolds Stress Model (RSM). Exact descriptions of the convection and production terms for each Reynolds stress component and the pressure-strain by the RSM improve the description of the flow-field in near-wall region and the aft-part of the cylinder compared to linear-eddy-viscosity models (EVM). The implementation of the combined AFT19-RSM model is discussed and verified for different grid resolutions for a zero-pressure-gradient (ZPG) flat-plate. An enhanced anisotropic description of the Reynolds stress tensor in the near-wall region is predicted by the AFT19-RSM compared to Boussinesq-hypothesis closure. As an application of the model proposed in this paper, a two-dimensional (2D) analysis is performed for flow around a circular cylinder at four Reynolds numbers, in regimes covering the subcritical to the trans-critical regime. Results demonstrate an improved prediction within the wake of the cylinder compared to experimental data. Consequently, the better description of the wake improves the tendency of the C_D estimation in the super-critical regime where there are two laminar separation bubbles on each side of the cylinder. The trans-critical prediction show that none of the transitional models tested, including the one proposed in this paper, can recover the fully-turbulent behaviour on the upstream face. This requires further investigation. The incorporation of the transitional framework to a RSM provides the capability of describing a laminar region, laminar separation, laminar separation bubble and turbulent reattachment. In addition, there is a slightly improved description of the flow on the downstream face of the cylinder compared to a more conventional Eddy Viscosity Model (EVM) approach.

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Contributors

Author: Jose M.Garro Fernandez

Author: David Angland

Author: Zhiwei Hu

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