Simulation of three-dimensional separation with a zonal near-wall approximation

The focus of the paper is on the performance of an approximate 'zonal' near- wall treatment applied within a LES strategy to the simulation of flow separating from a three-dimensional hill at high Reynolds numbers. In the zonal scheme, the state of the near-wall layer of the flow is described by parabolized Navier-Stokes equations solved on a...

Recent progress on flux-limiting based ILES

We review our recent progress in understanding the theoretical basis of Implicit Large Eddy Simulation (ILES) and fundamental features relating to its performance. We use the Modified Equation Analysis (MEA) to show that the leading order truncation error terms introduced by a particular class of hybrid methods provide implicit Subgrid Scale ...

Large scale urban simulations with MILES

Airborne contaminant transport in cities presents challenging new requirements for CFD. The unsteady flow physics is complicated by very complex geometry, multi-phase particle and droplet effects, radiation, latent, and sensible heating effects, and buoyancy effects. Turbulence is one of the most important of these phenomena and yet the overall...

Numerical study of the unsteady flow structures around train-shaped body subjected to side winds

Large-eddy simulation (LES) is made to investigate the flow around a generic train under side wind conditions. Two different side-wind yaw angles are used in the investigation: 35 and 90 degrees. The Reynolds numbers based on the height of the train and the freestream velocity are 300,000 and 370,000 for the 90 and 35 degrees yaw angles,...

Evaluation of the SST-SAS Model: Channel Flow, Asymmetric Diffuser and Axi-symmetric Hill

The SAS model (Scale Adapted Simulation) was invented by Menter and co-workers. The idea behind the SST-SAS k-omega model is to add an additional production term -- the SAS term -- in the omega equation, which is sensitive to resolved (i.e. unsteady) fluctuations. When the flow equations resolve turbulence, the length scale based on velocity...

ILES of shock waves and turbulent mixing using high-resolution Riemann solvers and TVD methods

This paper derives the implicit model for high-resolution MUSCL reconstruction-based upwind Godunov schemes for turbulent flows. A Mach number expansion of the numerical scheme allows analysis of the theoretical behaviour of the implicit subgrid model as the Mach number becomes small. This shows that different limiting methods within the same...

ILES and LES of Complex Engineering Turbulent Flows

The present study concerns the application of Large Eddy Simulation (LES) and Implicit LES (ILES) to engineering flow problems. Such applications are often very complicated, involving both complex geometries and complex physics, such as turbulence, chemical reactions, phase changes and compressibility. The aim of the study is to illustrate what...

A generalized patch AMR platform that uses cell centered or cell vertex solvers

A patch adaptive mesh refinement (AMR) platform is presented. Presently two Navier-Stokes solvers are available within this platform : a MUSCL and DG solver (FLUX AMR) and a multi-species MUSCL solver (MAJIC) for reacting flows. The first solver is based on cell centered approaches of finite volume type, the second solver is based on a cell...

Use of explicit filtering, second-order scheme and SGS models in LES of turbulent flow

In large eddy simulations (LES) using low-order finite-difference-type methods, the numerical error can be large in comparison to the effect of the sub-grid scale (SGS) model. In this paper, we study two approaches to explicit filtering which can reduce the numerical error involved. In the first approach, the non-linear convection term of the...

LES and URANS Unsteady Boundary Layer Strategies for Pulsating and Oscillating Turbulent Channel Flows Applications

The use of wall functions has been investigated for LES and URANS numerical simulation in pulsating and oscillating channel flow applications. The results show that the wall function approach is accurate in the so-called quasi-steady regime but there are discrepancies with the experimental results in the intermediate frequency range. A special...

Influence of Numerical Parameters for Large Eddy Simulations of Complex Flow Fields

Large eddy simulation (LES) becomes more and more important for the simulation of practical turbulent flows. The application for technically relevant, complex configurations leads to systems from around 500,000 up to several million degrees of freedom. For a statistical analysis of the turbulent flow field a large number of time steps have to be...

Large-eddy Simulation of Isotropic Homogeneous Decaying Turbulence

Simulations of three dimensional freely decaying homogeneous turbulence in a periodic cube have been used to examine in a detailed and quantitative manner the behaviour of a Large Eddy Simulation (LES) using implicit subgrid modelling. This paper details the form and behaviour of the implicit subgrid models for the Minmod and third order...