Across Wind Load Analysis Using CFD for Sustainable Design of Tall Structures

Abstract

With the advent of tall and complex shaped structures combined with urbanization, the structural designers are posed with a greater challenge to design the structures sustainable to rapid environmental changes. During the design of tall structures, wind loads acting on them are a major factor that needs to be considered. As a pre-requisite, the designer should have the information regarding wind environment of the region, wind forces on the structures and the response of the structure under these forces.

For tall and slender structures, across wind effects are more predominant than along wind effects. Recommendations in building codes for across wind effects are very limited. Several experimental studies were made to determine the across wind effects on structures. As wind tunnel tests are costlier and time consuming, an alternative computational fluid dynamics (CFD) approach has been emerged out to study these across wind effects.

This paper discusses on the across wind effects on tall structures like rectangular buildings and cooling towers in presence of other interfering structure using CFD analysis in ANSYS fluent. Experimental data of Kim et al. (2015) has been adopted to model the geometry of the structure and to simulate the wind environment around the structure in ANSYS fluent. LES (Large eddy simulations) turbulence model is considered to simulate the desired flow parameters around the structure. This 3D CFD model is validated with the experimental result of Kim et al. (2015). Further, the same scheme has been extended to cooling towers. Across wind effects acting on rectangular buildings and cooling towers are evaluated for the two cases: a. Stand alone case, b. interfering case with the same terrain category. In this manner, the response of the tall structures to across wind loading is studied using computational approach.