Numerical Simulation Study of the Structure of the Separated Flow Around Obstacles: Curved Edge Effect

Abstract

The existence of the obstacle in a flow certainly causes recirculation zone located upstream and downstream of the obstacle. These zones may represent pollution areas, where the pollution remains retained. In addition they are also very interesting in the area of flat plate solar collectors, with the aim of improving their performances. We focus in this work on the upstream edge adapted bright obstacle to the form of the appearance of the recirculation zone and see how it will reduce the recirculation zone in the flow. After a short description of the existent literature in the domain, we present some recent interesting works; a mathematical formulation is also given. The turbulent governing equations, based on the k-e model, are solved by the finite volumes method. The velocity and pressure terms of momentum equations are solved by SIMPLE (Semi- Implicit method for pressure-linked equation) method. A qualitative study of the flow around the obstacle will give us a good idea of the behavior of this recirculation zone. The contours and mean profiles of velocity, rate of turbulence and turbulent dissipation rate are presented for a typical case and at a Reynolds Number of 5×104,5×105 and 5×106.This work allows us to conclude that the dimensions of the recirculation zone are much lower for curved edge obstacle than for the rectangular one, this for all the three values of Reynolds number that have been considerate and the rate of turbulence remain very high above the two models of obstacles