in this study, the turbulent kinetic energy redistribution process is investigated. to this aim, the direct numerical simulation (dns) of incompressible flow of a newtonian fluid through a channel at a shear reynolds number of reτ = 180 is used to produce a flow data base. then, these data are statistically analyzed. the turbulent kinetic energy redistribution is studied using the pressure-stra...

In this research, hydrodynamics of the Bubble Train Flows (BTF) in circular capillaries has been investigated by Direct Numerical Simulation (DNS).The Volume of Fluid Based (VOF) interface tracking method and streamwise direction periodic boundary conditions has been applied. The results show that there exists an appropriate agreement between DNS and experimental correlation results. The re...

Abstract. The present study adresses the turbulent flow over a wavy surface by direct numerical simulation (DNS). Compared to classical channel flow the wavy surface structure adds a degree of complexity to the flow by inducing streamline curvature, flow separation and flow reattachment, thus leading to flow situations which are often present in relevant technical and geophysical applications. ...

We review the direct numerical simulation (DNS) of turbulent flows. We stress that DNS is a research tool, and not a brute-force solution to the Navier-Stokes equations for engineering problems. The wide range of scales in turbulent flows requires that care be taken in their numerical solution. We discuss related numerical issues such as boundary conditions and spatial and temporal discretizati...

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-

in this paper, reduced order proper orthogonal decomposition method has been used for simulation of unsteady incompressible flow fields. after projection of the governing equations along pod modes, a low-dimensional dynamical system is achieved. normally, standard low-dimensional models, due to some reasons, do not predict time variations of flow field accurately. accuracy of dynamical system h...

Separating flow in a channel with streamwise periodic constrictions is investigated using direct numerical simulation (DNS), large eddy simulation (LES), and wall-modeled LES (WMLES). The Reynolds number based on the hill height and the bulk velocity above the hill crest is 10,595. The results presented include mean velocities, Reynolds stresses, and separation/reattachment points. High-resolut...

Direct numerical simulation results of aeolian tones generated by a two-dimensional obstacle (circular cylinder, square cylinder, NACA0012 airfoil) in a uniform flow are presented and the generation and propagation mechanisms of the sound are discussed. The unsteady compressible Navier-Stokes equations are solved by a highly-accurate finite difference scheme over the entire region from near to ...

Direct numerical simulation (DNS) is the most accurate method of solving turbulence in fluids. In DNS the Navier-Stokes equations are solved on a fine mesh to resolve all the spatial and temporal scales present in the flow. In order to ensure high accuracy of the discrete solution, schemes with low numerical errors are necessary. Spectral methods with their low dissipation and dispersion errors...

Direct numerical simulation (DNS) of turbulent flows is widely recognized to demand fine spatial meshes, small timesteps, and very long runtimes to properly resolve the flow field. To overcome these limitations, most DNS is performed on supercomputing machines. With the rapid development of terascale (and, eventually, petascale) computing on thousands of processors, it has become imperative to ...