The influence of Reynolds stresses on roof pressure fluctuations

This paper describes a further development of the quasi-steady theory to in clude the effect of <(uw)over bar> Reynolds stress on building surface pres sures. The theory predicts that <(uw)over bar> Reynolds stresses have a sig nificant influence in suppressing roof pressure fluctuations, even tho ugh its magnitude is typically much smaller than variances for wind velocity co mponents in the atmospheric boundary layer. Experimental evidence for this is provided by a wind tunnel investigation of roof pressures on a 1 : 50 sc ale model of the Texas Tech University (TTU) test building. This novel resu lt immediately explains the overprediction of RMS roof pressure coefficient s by the theory that incorporates only the three turbulence components. It also explains the apparent loss of mid-frequency response of roof pressures reported in the past. It is speculated that Reynolds stresses are also res ponsible for shear layer instabilities that are believed to be responsible for a number of observed phenomena related to roof pressures. (C) 1999 Else vier Science Ltd. All rights reserved.