Wind pressure measurements on flat roofs using scaled models

A flat roof surface is known to be subjected to unusually high suction associated with a pair of vortices created under diagonally skewed wind. Prediction of the wind load and its influence on the roof system is an important engineering topic but wind tunnel testing of this situation is not easy with a scaled model. Considering the physics of wind flow for the most critical case, a possibility to use a half-roof configuration instead of the whole roof has been investigated. Results are found to be encouraging, which allows the use of much larger scale or even full-scale models to carry out testing including more accurate structural details of roofing system, such as flexible membranes.