Improved convergence characteristics of two-equation turbulence models on unstructured grids

2021 ◽  
Vol 230 ◽  
pp. 105127
Author(s):  
Yair Mor-Yossef
Volume 4 ◽  
2004 ◽  
Author(s):  
Branislav Basara ◽  
Ales Alajbegovic ◽  
Decan Beader

The paper presents calculations of flow in a mixing vessel stirred by a six-blade Rushton impeller. Mathematical model used in computations is based on the ensemble averaged conservation equations. An efficient finite-volume method based on unstructured grids with rotating sliding parts composed of arbitrary polyhedral elements is used together with various turbulence models. Besides the standard k-ε model which served as a reference, k-ε-v2 model (Durbin, 1995) and the recently proposed hybrid EVM/RSM turbulence model (Basara & Jakirlic, 2003) were used in the calculations. The main aim of the paper is to investigate if more advanced turbulence models are needed for this type of CFD applications. The results are compared with the available experimental data.


Author(s):  
Zengrong Hao ◽  
Xiaodong Ren ◽  
Yin Song ◽  
Chunwei Gu

A framework for the simulations of conjugate heat transfer (CHT) problems using discontinuous Galerkin (DG) methods on unstructured grids is presented. The compressible fluid dynamic equations and solid heat conduction equations are discretized into the explicit DG formulations simultaneously. The Bassi-Rebay method is used in the gradients computation inside both fluid and solid domains. Fully coupled strategy based on the data exchange process via the numerical flux of interface quadrature points is devised. Various turbulence models and the local-variable-based transition model γ -Reθ are assimilated into the unified algorithm framework. The feasibility of the methodology is validated by some test cases. The work can be viewed as a primary attempt towards further investigations of DG and other high-accuracy methods applications in the engineering CHT problems.


Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 81 ◽  
Author(s):  
Guillermo Araya

One of the key factors in simulating realistic wall-bounded flows at high Reynolds numbers is the selection of an appropriate turbulence model for the steady Reynolds Averaged Navier–Stokes equations (RANS) equations. In this investigation, the performance of several turbulence models was explored for the simulation of steady, compressible, turbulent flow on complex geometries (concave and convex surface curvatures) and unstructured grids. The turbulence models considered were the Spalart–Allmaras model, the Wilcox k- ω model and the Menter shear stress transport (SST) model. The FLITE3D flow solver was employed, which utilizes a stabilized finite volume method with discontinuity capturing. A numerical benchmarking of the different models was performed for classical Computational Fluid Dynamic (CFD) cases, such as supersonic flow over an isothermal flat plate, transonic flow over the RAE2822 airfoil, the ONERA M6 wing and a generic F15 aircraft configuration. Validation was performed by means of available experimental data from the literature as well as high spatial/temporal resolution Direct Numerical Simulation (DNS). For attached or mildly separated flows, the performance of all turbulence models was consistent. However, the contrary was observed in separated flows with recirculation zones. Particularly, the Menter SST model showed the best compromise between accurately describing the physics of the flow and numerical stability.


2003 ◽  
Vol 32 (3) ◽  
pp. 403-430 ◽  
Author(s):  
D.G. Koubogiannis ◽  
A.N. Athanasiadis ◽  
K.C. Giannakoglou

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