Reduced Frequency and Power Spectra of Wind Pressure of a Tall Building Having "Z" Shape in Plan

Abstract

This study envisages a tall building model's dynamic behaviour with a 'Z' shape in plan and exposed to cyclonic wind tested using numerical simulation technique. The computational Fluid Dynamics (CFD) simulation tool of ANSYS-CFX is adopted in the present study. The geometric scale is considered as 1:300, whereas the velocity scale is taken to be 1:5. Wind streamlines under different wind occurrence angles on the building are displayed perceptibly, ensuring vortex shedding at the region of disturbed flow where the wind suction and pressure amalgamates. The peak wind pressures and suctions at building facets are presented under different wind angles. Again the features of normalized power spectra of wind pressure at the top part, main body, and bottom part of the building subjected to wind azimuths ranging from 0° to 150° are presented. It is found that at the bottom part of the building, the peak values of standardized power spectra occur in the low-frequency range, although, at the top part and main body of the building, the vortex shedding energy intensifies at relatively high reduced frequencies. The determination of reduced frequency is of paramount importance to evade resonance under wind tempted shakings of soaring buildings.