Numerical Investigation of Interference Effects of Two Rectangular Tall Buildings on Aerodynamic Response

Abstract

In this numerical investigation, the effect of upstream and downstream interference of two identical tall buildings was evaluated using the computational wind engineering (CWE) method. In order to simulate three-dimensional turbulent wind flow with Reynolds numbers in the range of 1.4×〖10〗^4<Re<8×〖10〗^4, the Large Eddy Simulation (LES) model was used. Mean and fluctuating coefficients of drag and lift and pressure distribution were used as the main criteria to evaluate the aerodynamic response of the principal building in different conditions of interference. Streamlines and vorticity contours were presented and their relationship to aerodynamic results was interpreted to provide a better understanding of the physics of the problem. According to the results, the shielding effect of the interfering building in most interference cases led to a reduction of the mean drag coefficient of the principal building compared to the isolated case. Compared to the isolated building, depending on the location of the interfering building, the fluctuating lift coefficient either increases or decreases.Upstream interfering buildings with sufficient distance to the principal building lead to an increase in the fluctuating lift coefficient of approximately about 50 percent. While, the fluctuating lift coefficient of the principal building decreases up to 37 percent, due to the closely spaced tandem interference states. While the mean pressure coefficient at the windward surface is not significantly sensitive to the interference states, it is strongly influenced by the different states of the interference at the lateral and leeward surfaces. Aerodynamic parameters were less sensitive to Reynolds number variations due to the fixed position of the flow separation in the sharp corners of the rectangular section and the zero angle of attack in this study. Changes in the Reynolds number resulted in variations of about 4 to 10% in the drag and lift coefficients of the principal building.