In this paper, the performance of Reynolds Averaged Navier Stokes (RANS) simulations was evaluated to predict the flow structure developed by the presence of a sidewall obstruction in a uniform open-channel shallow flow. The study of these flow structures is important because they present in several real world configurations, such as groynes in rivers, where the erosion processes, mass transpor...

RANS-LES hybrid approaches have become increasingly popular. One way to construct a hybrid approach is to apply separate flow solvers to components of a complex system and to exchange information at the interfaces of the domains. For the LES flow solver, boundary conditions then have to be defined on the basis of the Reynolds-averaged flow statistics delivered by a RANS flow solver. This is a c...

The turbulent potential model is a RANS model that avoids modeling the Reynolds stress tensor. As a result it has the ability to obtain the physical accuracy of Reynolds stress transport equation models at a cost and complexity comparable to popular two equation models. The model’s ability to predict channel flow, free-shear layers, homogeneous shear flow, stagnation point flow, backward facing...

Developing boundary layer flow and the flow over a backward-facing step are studied here. The LRN PANS k − ε [1] and the WALE turbulence model [2] are used as SGS models. The PANS (Partially AveragedNavier-Stokes) modelling approach [3, 4] is a modified k − ε model that can operate in both RANS and LES mode. An extension of PANS based on a four-equation k− ε− ζ − f model was recently proposed [...

We present results with a parallel CFD code that computes steady-state solutions of the Reynolds-Favre averaged Navier-Stokes equations for the simulation of the turbulent motion of compressible and incompressible Newtonian fluids. We report on preliminary experiments on 2D and 3D problems, for both internal and external flow configurations. In this communication we present numerical results wi...

This paper is addressing of a coupling Large-eddy simulation (LES) and RANS turbulence models with mixture fraction/probability density function as combustion model. The two have been implemented to simulate ethanol-air spray combustion. gas phase described the Eulerian approach while liquid designed using Lagrangian framework. LES/PDF obtained statistically. sub-grid scale energy equation used...

The paper presents a comparison of several hybridization between RANS and LES, and their potential and limitations in an industrial context. The first part of the paper addresses an often eluded problem in the hybrid RANS/LES community: the importance of the baseline statistical model. A new robust low-Reynolds number eddy-viscosity model, derived from a Reynolds-stress model and accounting for...

Predictive capability of RANS and LES models to calculate incipient cavitation of water in a step nozzle is assessed. The RANS models namely, Realizable k-ɛ, SST k-ω and Reynolds Stress Model did not predict any cavitation, due to the limitation of RANS models to predict the low pressure vortex cores. LES WALE model was able to predict the cavitation by capturing the shear layer instability and...

CFD modeling using RANS and LES of pollutant dispersion in a three-dimensional street canyon is investigated by comparison with measurements. The purpose of this study is to confirm the accuracy of LES in modeling plume dispersion in a simple street canyon model and to clarify the mechanism of the discrepancy in relation to RANS computation. Simple LES modeling is shown by comparison with wind ...