Fluid turbulence is commonly modeled by the Navier-Stokes equations with a large Reynolds number. The simulation of turbulence model is known to be very difficult. We study artificial spectral viscosity models that render the simulation of turbulence tractable. The models introduce several parameters. We show that the models have solutions that converge, in certain parameter limits, to solution...

Energy transfers within LES and DNS grids are studied. The spectral eddy viscosity for conventional dynamic Smagorinsky and variational multiscale LES methods are compared with DNS results. Both models underestimate the DNS results for a very coarse LES, but the dynamic Smagorinsky model is significantly better. For moderately to well-refined LES, the dynamic Smagorinsky model overestimates the...

Abstract Turbulence pervades most flows of engineering interest, and its prediction remains a challenge on both accuracy cost. One promising predictive approach that reduces cost combines large‐eddy simulation (LES) with based Reynolds averaged Navier–Stokes equations (RANS). This study presents method to overcome stability issues associated these hybrid LES‐RANS methods. The developed involves...

This study is inspired by the observation and hypothesis that the spreading and decay behaviors of a jet directly depend on the momentum-mixing mechanism between the jet and surrounding fluid. This mixing behavior is dictated by the kinematic viscosity ν for a laminar jet, which can be dramatically enhanced in a turbulent flow and is represented by the eddy viscosity ε. Similarly, pulsation in ...

The possibility of a dynamical core helium Ñash has been studied with two-dimensional hydrodynamic simulations using three separate turbulence models for the treatment of time-dependent convection. Two of these are simple algebraic eddy viscosity models. The third model involves a separate equation for the turbulent kinetic energy density, which then feeds into an expression for the eddy viscos...

A model for the kinematic eddy viscosity has been developed which accounts for the turbulence produced as a result of jet interactions between adjacent streams as well as the turbulence initially present in the streams. In order to describe the turbulence contribution from jet interaction, the eddy viscosity suggested by Prandtl has been adopted, and a modification has been introduced to accoun...

Characteristics of rotor blade tip clearance flow in axial compressors can significantly affect their performance and stable operation. It may also increase blade vibrations and cause detrimental noises. Therefore, this paper is contributed to investigate tip leakage flow in a low speed isolated axial compressor rotor blades row. Simulations are carried out on near-stall condition, which is val...

This paper presents a CFD modelling study of the bubble driven hydrodynamics in aluminium reduction cells. A time-averaged (steady state) bubble driven flow model has been developed using a full scale air-water model of part of an aluminium reduction cell as a test-bed. Simulated results have been compared with experimental data taken under similar conditions using Particle Image Velocimetry (P...

Motivated by the recent interest in ocean energetics, the widespread use of horizontal eddy viscosity in models, and the promise of high horizontal resolution data from the planned wide-swath satellite altimeter, this paper explores the impacts of horizontal eddy viscosity and horizontal grid resolution on geostrophic turbulence, with a particular focus on spectral kinetic energy fluxes P(K) co...