Direct numerical simulations (DNS) of the incompressible Navier-Stokes equations are limited to relatively low-Reynolds numbers. Therefore, dynamically less complex mathematical formulations are necessary for coarse-grain simulations. Regularization and eddy-viscosity models for Large-Eddy Simulation are examples thereof. They rely on differential operators that should be able to capture well d...

Flow characteristics are presented of simulation results of plane impinging jets at high nozzle-plate distances, with two k-ω based hybrid RANS/LES (Reynolds Averaged Navier–Stokes/Large–Eddy Simulation) models and a k-ω RANS model. The first hybrid RANS/LES model is obtained by substitution of the turbulent length scale by the local grid size in the destruction term of the turbulent kinetic en...

In this work we propose an effective viscosity criterion for the stabilization of annular gas-liquid and liquid-particle flows and an inertial mechanism which drives waves into slugs in slugging gas-liquid flows. Annular flow is stable when the fluid having the higher effective viscosity occupies the core region and the lower viscosity fluid is the annulus. The eddy viscosity criterion is shown...

In this paper we provide an error analysis of a subgrid scale eddy viscosity method using discontinuous polynomial approximations, for the numerical solution of the incompressible Navier-Stokes equations. Optimal continuous in time error estimates of the velocity are derived. The analysis is completed with some error estimates for two fully discrete schemes, that are first and second order in t...

Two-parametric eddy viscosity (TPEV) and other spectral characteristics of two-dimensional (2D) turbulence in the energy transfer sub-range are calculated from direct numerical simulation (DNS) with 5122 resolution. The DNS-based TPEV is compared with those calculated from the test field model (TFM) and from the renormalization group (RG) theory. Very good agree-

A = constant b = vortex spacing C = constant to adjust turbulent spreading q = rms turbulence velocity R = mean radius T = parameter for vortex age t = time u = axial velocity v = lateral velocity w = descent speed y = spanwise coordinate, positive for port vortex z = vertical coordinate, positive pointing upwards = circulation = eddy dissipation rate = standard deviation = (effective) kinemati...

The effect of the spanwise discretisation on numerical calculations of the turbulent flow around a circular cylinder is systematically assessed at a subcritical Reynolds number of 10000 in the frame of three-dimensional large-eddy simulation. The eddy-viscosity k-equation subgrid scale model is implemented to evaluate unsteady turbulent flow field. Large-eddy simulation is known to be a reliabl...

We describe the use of eddy current brakes as fast turn-on, tunable, linear dampers for haptic rendering using a prototype haptic device outfitted with eddy current brakes. We show that at the speeds typically required for haptic interaction, eddy-current-induced drag is proportional to velocity. We also show that a modulation rate of approximately 250 Hz can easily be achieved with off the she...

In this paper we provide an error analysis of a subgrid scale eddy viscosity method using discontinuous polynomial approximations for the numerical solution of the incompressible Navier–Stokes equations. Optimal continuous in time error estimates of the velocity are derived. The analysis is completed with some error estimates for two fully discrete schemes, which are first and second order in t...

Eddy-viscosity closures for large eddy simulations (LES) of atmospheric boundary layer dynamics include a parameter (Smagorinsky constant cs), which depends upon physical parameters, such as distance to the ground, atmospheric stability, and strain. A field study [Horizontal Arrays Turbulence Study (HATS)] specifically designed to measure turbulence quantities of interest in LES, such as the pa...