Re-visiting the wind tunnel method for determining wind loads on low buildings

Overview

The Scruton Lecture is part of ICE’s prestige event series and is held in honour of Christopher ‘Kit’ Scruton. Scruton played a role in the evolution of wind engineering from pragmatic provider of wind loading data to ‘prophetic’ predictor of structural response of increasingly complex structures in increasingly chaotic flows.

The use of boundary layer wind tunnels for determining wind loads on low-rise buildings has always been a challenge since there is a trade-off between the simulation of the atmospheric boundary layer (ABL) and the size and accuracy of the building model. To fully simulate the turbulence spectrum in most wind tunnels typically requires a small model scale and a relatively low Reynolds number.

In contrast, a larger model scale improves the Reynolds number and allows for more accurate building features to be modelled, but at the expense of the accuracy of the wind simulation. This conundrum will be examined in the lecture. In particular, recent research into the fundamental mechanisms related to peak pressures on low building surfaces along with theoretical developments suggest that mismatches in the simulated ABL characteristics can be corrected implying that larger model scales can be used when needed.