Wind effects on ‘Z’ plan-shaped tall building: a case study

Rajdip Paul,Sujit Kumar Dalui

doi:10.1007/s40091-016-0134-9

Abstract

The present paper is centered on the study to understand the behavior of various surfaces of a ‘Z’ plan-shaped tall building under varying wind directions. For that purpose, computational fluid dynamics (CFD) package of ANSYS is used. The length scale is considered as 1:300. Force coefficients both in the along and across wind direction as well as the external surface pressure coefficients for different faces of the object building are determined and listed for wind incidence angle 0°–150° with increment of 30°. The wind flow pattern around the building showing flow separation characteristics and vortices are presented. The variation of wind pressure on different surfaces of the building is clearly shown by contour plots. The nature of deviation of external pressure coefficients along the height of the building as well as along the perimeter of the building for different wind angles of attack is presented. The force coefficient (C f) along the X direction is extreme for 15° wind angle and along Y direction it is maximum for 60° angle of attack. Unsteady vortices are generated in the wake region due to a combination of positive and negative pressure in the windward and leeward faces, respectively.

Highlights

As buildings are cantilever structures, there is generation of base moment whenever it is under lateral load
The force coefficient (Cf) along the X direction is extreme for 15° wind angle and along Y direction it is maximum for 60° angle of attack
Force coefficients (Cf) along the X and Y direction are determined using the formula Cf = F/(P 9 A), where ‘F’ is the total force exported from numerical simulation in the desired direction corresponding to the wind angle, ‘P’ is the wind pressure and ‘A’ is the surface area exposed to the wind

Summary

Introduction

As buildings are cantilever structures, there is generation of base moment whenever it is under lateral load. The wind tunnel model experiment and numerical simulation using computational fluid dynamics (CFD) are the available research tools to get deeper insight into the behavior of gigantic structures subjected to turbulent wind load. Bhatnagar et al (2012) presented the results of a wind tunnel study in an open circuit boundary layer flow condition, carried out on a model of low-rise building with sawtooth roof. Raj et al (2013) carried out an experimental boundary layer wind tunnel study to observe the effect of base shear, base moment and twisting moment developed due to wind load on a rigid building model having the same floor area, but different cross-sectional shapes with the variation of wind incidence angle. The dissimilarity in temperature offers rise to the gradients of pressure which set air in motion

Power law:

Results and discussion

Conclusion