Innovation Award Finalist: Hi-Res CFD for Wind Loading of Tall Buildings

Nick Wirth
Founder
Wirth Research, Bicester

Rob Rowsell
Engineering Manager
Wirth Research, Bicester

Advancing Computerized Wind-Loading Tests to the Next Level

Accurate analysis of the mean and resonant wind loads is vital for the structural design of tall buildings. Whereas physical Wind Tunnel Testing (WTT) to determine these loads is still accepted by the industry as the necessary default practice, the wind engineering community recognizes that a time will come when computational fluid dynamic CFD modelling is able to accurately model the interaction of wind and buildings. In the meantime, a combination of wind tunnel testing and CFD modelling is often undertaken.

High Resolution Computational Fluid Dynamics (HRCFD) is one of many experimental computational methodologies which could potentially move the industry forward. Ultimately, the objective would be where CFD can provide an accurate full pressure map on the building surfaces. However we are not at that point yet. The technology has been adapted from motorsport racing, where aerodynamics is a fundamental factor in split-second timing differences between winning or losing a race. The process uses a full-scale digital model of a tall building, accurate to detailed features of 100 millimeters or smaller when necessary, placed within a surrounding area of up to 10 kilometers’ radius. Wind conditions are simulated by using an atmospheric boundary layer profile and data from many decades of local historical wind data.

HRCFD takes advantage of recent advances in super-computing to model flow conditions, with correlations back to physical data when it exists. Novel methods of model generation, coupled with a rapid and flexible solving capability, lead to the potential to provide fast feedback into the design loop. The modeling environment is discretized into several hundred million cells, from which an initial solution can be obtained in a matter of hours to days, depending on the computing environment available. While HRCFD is still untested on real buildings, the advancement of computer aided engineering is occurring at a rapid pace. Bestowing of Finalist status in the Innovation Award category for this method is thus recognizing the potential advancement in the field, and likely future importance of such technologies.