Numerical simulation and optimization study of surface pressure and flow field around a triangular prism behind a porous fence

Abstract

The flow structure around upright porous fences and a triangular prism was numerically investigated by using the RNG k-e turbulence model. The numerical method was validated by comparing the simulations with the experimental data, and then the effects of porosity and height of the wind fence on the flow field around the prism model and surface pressures were studied. The aim of this paper is to achieve the best shelter effect of a porous fence on the triangular prism located behind the fence with the height of 0.5h and 1.0h respectively, where h is the height of the prism. The gradient algorithm was adopted as the optimization algorithm to determine the optimum porosity of the wind fence. Three objective functions were considered to minimize (1) the sum of the absolute values of the mean pressure coefficients on the prism surface; (2) the total turbulence kinetic energy around the prism model, and (3) the total values of the peak velocity ratios involving velocity and turbulence. The numerical results showed that a porous fence with the height of about 0.5h–1.0h seems to be most effective in reducing the absolute value of the mean pressure coefficient on the model surface. Additionally, all three objective functions were capable of finding an optimal shelter performance of porous fences on the prism with surface pressure or flow characteristics considerations.