Direct numerical simulation-based characterization of pseudo-random roughness in minimal channels

Direct Numerical Simulation of the Wake Flow Behind a Cylinder Using Random Vortex Method in Medium to High Reynolds Numbers

Direct numerical simulation of turbulent flow behind a cylinder, wake flow, using the random vortex method for an incompressible fluid in two dimensions is presented. In the random vortex method, the primary variable is vorticity of the flow field. After generation on the cylinder wall, it is followed in two fractional time step in a Lagrangian system of coordinates, namely convection and diffu...

Absolute Permeability Calculation by Direct Numerical Simulation in Porous Media

Simulating fluid flow at micro level is an ongoing problem. Simplified macroscopic flow models like Darcy’s law is unable to estimate fluid dynamic properties of porous media. The digital sample reconstruction by high resolution X-ray computed tomography scanning and fluid-dynamics simulation, together with the increasing power of super-computers, allow to carry out pore-scale simulations throu...

Some aspects of pseudo random binary array-based surface characterization

In this paper, we report on an algorithm which we have developed to model three-dimensional (3-D) scenes with color-coded Pseudo Random Binary Arrays (PRBAs). The algorithm comprises three steps: first, a graph recovery, then an iterative reinspection, and finally application of the PRBA information. The combination of these three steps allows the algorithm to become auto adaptive to the surfac...

Direct Numerical Simulation of Hypersonic Flow over a Blunt Cone with Axisymmetric Isolated Roughness

The ability of a finite roughness element to suppress the hypersonic second-mode instability on a cone is explored. A new code for simulating discrete roughness using a body-fitted grid over an analytic shape is developed. Linear stability analysis is performed on the Mach 8 meanflow of a 7◦ half-angle straight cone. The resulting N-factor analysis determines the second-mode frequency of 240 kH...

Direct Numerical Simulation of vortices