Obstacle array drag coefficient parametric response surface analysis

Abstract

Throughout literature, one finds where numerous methodologies and models have been developed to predict the effect of surface roughness on a flat surface. Many of the models utilize a drag coefficient as one of the necessary parameters. In urban settings with groups of buildings, the drag coefficient on an individual obstacle would be determined by parameters like wind direction and the relative positioning of a building, in addition to Reynolds number and shape. Computational experiments were performed to simulate the fluid flow around a single row and two rows of “cube” obstacles. Based on dimensional analysis, the drag coefficient was formulated as a function of four input variables. The effect of these input variables on the drag coefficient was individually studied. Finally, using the central composite design method and the numerically obtained experiment data, a second-order mathematical model was devised for the drag coefficient as a function of the four input variables.