Graeme S. Wood

Physical and numerical modelling of thunderstorm downbursts

Abstract In this study, a static continuous impinging jet has been used to simulate a thunderstorm downburst. Velocity characteristics have been investigated at various positions in the flow over flat terrain, and over simple topographic features, thereby yielding topographical speed-up factors. A generic empirical equation describing the development of the velocity profile over a flat board has been developed. Comparison with previous works with impinging jets and conventional boundary layer flow speed-up factors has been completed. Speed-up factors were similar at the crest of the embankment, but dropped off rapidly behind the crest compared with boundary layer flow. Preliminary studies using computational fluid dynamics to predict the flow regime over topographical features has been shown to give reasonable agreement.

Interference effects on wind-induced coupled motion of a tall building

Abstract Interference effects from neighbouring buildings on wind-induced coupled translational–torsional motion of tall buildings have been investigated through a series of wind tunnel aeroelastic model tests. Interference effects on the CAARC standard tall building by an 8:1:1 tall interfering building both upstream and downstream were investigated. The results indicated a significant increase in responses at the critical wind speed where the frequency of the shed vortices originated from the interfering building coincides with the modal natural frequency of vibration of the principal tall building. The along-wind, cross-wind, and twisting moment responses of the principal building were significantly increased when the interfering building was located diagonally upstream. A more substantial increase in responses was evident when the interfering building was located directly upstream from the principal building.