Unsteady Vortex Structures in the Wake behind Bluff Bodies

Unsteady features of bluff body wake with application to building wake length

This study is targeted at obtaining fluctuating characteristics of building wakes through measurement of unsteady velocity fields with time-resolved particle image velocimetry (PIV). Proper orthogonal decomposition is applied to the PIV data to identify low-dimensional substructures of the building wake. This leads to a more reliable estimation of the fluctuating ground-level length of the buil...

Numerical Simulation of the Wake Flow Behind an Ellipse using Random Vortex Method (RESEARCH NOTE)

Direct numerical simulation of the wake flow around and behind a planar ellipse using a random vortex method is presented. Fluid is considered incompressible and the aspect ratios of ellipse and the angles of attacks are varied. This geometry can be a logical prelude to the more complex geometries, but less time dependent experimental measurements are available to validate the numerical results...

Modeling the Wake Behind Bluff Bodies for Flow Control at Laminar and Turbulent Reynolds Numbers Using Artificial Neural Networks

Longitudinal vortex structures in a cylinder wake

Recently, flow visualizations by Wei and Smith,’ Williamson,’ Welsh et a1.,3 and Bays-Muchmore and Ahmed4 have shown that three-dimensional (3-D) vertical structures develop in the wake of a bluff body. The 3-D vertical structures were found to include pairs of counterrotating longitudinal vortices superimposed on the nominally two-dimensional (2-D) Kirmin vortex street as speculated by Grant’ ...

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...