A Large-Eddy Simulation of several cycles of a spark-ignition engine with port fuel injection has been performed. The investigated engine is a modified Rotax-engine with one cylinder and four valves, built and measured (Heidenreich, Private communication) by the Institute of Reciprocating Engines of the University of Karlsruhe (IFKM). A recently modified (Magagnato et al., 2008) progress variab...

We propose a stabilized subgrid finite-element method for the two-dimensional 2D nonstationary incompressible Naver-Stokes equation NSE . This method yields a subgrid eddy viscosity which does not act on the large flow structures. The proposed eddy viscous term is constructed by a fluctuation operator based on an L2-projection. The fluctuation operator can be implemented by the L2-projection fr...

Large-eddy simulations of decaying turbulence and turbulent channel ow using the stretched-vortex subgrid-stress model are presented and discussed. In the stretched-vortex model, the subgrid turbulence is assumed to consist of vortices whose orientations are determined by the resolved velocity eld. This, combined with a relationship connecting the subgrid stresses to the vortex-structure orient...

This article presents a new turbulence closure based on the k-ω SST model for predicting turbulent flows of Herschel–Bulkley fluids, including Bingham and power-law fluids. The has been calibrated with direct numerical simulations (DNS) data fully-developed pipe flow shear-thinning viscoplastic shows good agreement in mean velocity, average viscosity, shear stress budget friction factor. latter...

The filtered fluid dynamic equations are discretized in space by a high-order spectral difference(SD) method coupled with large eddy simulation (LES) approach. The subgrid-scale stress tensor is modelled by the wall-adapting local eddy-viscosity model (WALE). We solve the unsteady equations by advancing in time using a second-order backward difference formula (BDF2). The nonlinear algebraic sys...

The potential of the nonaxisymmetric magnetic instability to transport angular momentum and to mix chemicals is probed considering the stability of a nearly uniform toroidal field between conducting cylinders with different rotation rates. The fluid between the cylinders is assumed as incompressible and to be of uniform density. With a linear theory the neutral-stability maps for m = 1 are comp...

The lattice Boltzmann method has become a widely used tool for the numerical simulation of fluid flows and in particular of turbulent flows. In this frame the inclusion of subgrid scale closures is of crucial importance and is not completely understood from the theoretical point of view. Here, we propose a consistent way of introducing subgrid closures in the BGK Boltzmann equation for large ed...