A compressible finite volume formulation for large eddy simulation (LES) of turbulent channel flows was extended to solve the turbulent flows in pipes and annular passages. A general finite volume scheme was developed based on conservation equations in Cartesian coordinates with non-Cartesian control volumes. A dual-time stepping approach with time derivative preconditioning was employed and ti...

We report a large-eddy simulation (LES)/probability density function (PDF) study of a non-premixed CO/H2 temporally-evolving turbulent planar jet flame, which has previously been studied using direct numerical simulations (DNS) with a skeletal chemical mechanism. The flame exhibits strong turbulence– chemistry interactions resulting in local extinction followed by re-ignition. In this study, th...

This paper describes the reviews of recent works in analysis, modeling, and simulation motion a non-spherical particle. The particles was analyzed detail by means fully resolved direct numerical (DNS). From DNS data, PDF-based drag coefficient model proposed applied to particle dispersion an isotropic turbulent flow assess effect shape comparing it with spherical Moreover, large-eddy (LES) axia...

We present three-dimensional direct numerical simulations (DNS) of the Kida vortex flow, a prototypical turbulent flow, using a novel high-order lattice Boltzmann (LB) model. Extensive comparisons of various global and local statistical quantities obtained with an incompressible-flow spectral element solver are reported. It is demonstrated that the LB method is a promising alternative for DNS a...

This numerical study based on high-order finite-difference schemes presents LES-NWR (Large Eddy Simulation with near-wall resolution) of turbulent channel flows up to Reτ=5200 using non-explicit approaches for which dissipation is introduced via the discretisation viscous terms Navier-Stokes equations. These models are cheaper than explicit LES as no extra needed in equations account contributi...

We develop a reduced order model for large-scale unsteadiness (vortex shedding) in a two-dimensional diffuser and study the mechanisms of active flow separation control. This model can estimate the vortex shedding frequency for inviscid flows by accounting for the accumulated vorticity flux in the diffuser. The model can also predict the stagnation pressure loss, which consists of two parts: A ...

An overview of removal and re-entrainment of particles in turbulent flows is presented. The procedure for the direct numerical simulation (DNS) of the Navier-Stokes equation via a pseudospectral method for simulating the instantaneous fluid velocity field is described. Particle removal mechanisms in turbulent flows in a duct are examined and effects of the near-wall coherent eddies on the parti...

Direct numerical simulations, (DNS), are used to simulate the decay of an isotopic, turbulent, chemically-reacting flow at high temperatures. The independent parameters that govern the physical process are introduced. The different effects from each of the parameters in the flow are explained by using the results from the DNS. It is found that there is a feedback mechanism between the chemical ...

The separation of a turbulent boundary layer, which is encountered in devices such as airfoils, diffusers and turbomachinery, is one of the most challenging research topics in fluid mechanics. Its understanding and its prediction with turbulence models are however still not satisfactory. The reason may be partly due to a shortage of reliable data from numerical simulations, which account for Re...

A spectral element—Fourier method (SEM) for Direct Numerical Simulation (DNS) of the turbulent flow of non-Newtonian fluids is described and the particular requirements for non-Newtonian rheology are discussed. The method is implemented in parallel using the MPI message passing kernel, and execution times scale somewhat less than linearly with the number of CPUs, however this is more than compe...