FLOW PATTERNS AND PRESSURE FIELD AROUND A FULL-SCALE BUILDING

This paper describes measurements of the flow patterns and pressure field around a low-rise portal framed building (24 m long x 13 m span x 4 m eaves height, 10-degrees roof pitch) on which extensive full-scale wind load measurements have been made. Flow patterns have been observed using smoke, generated from a smoke canister, nylon tufts attached to the surface of the building, and on one occasion the deposition of snow on and around the building. These techniques provide some quantitative information about the flow pattern but are primarily qualitative, aiding an understanding of the three-dimensional flow field for comparison with wind-tunnel studies and computational fluid dynamics predictions. A technique, using static pressure probes, is described which provides more quantitative information on the pressure field around the building for a wind direction transverse to the line of the ridge. Measurements were made on the major axes of the building, extending to 50 m upstream, 10 m downstream, and 20 m to one side. Over 220 hours of recordings were made when the mean wind speed at building ridge height was greater than 8 m/s. Results of these pressure field measurements are presented and compared with predictions from computational fluid dynamics using a k-epsilon model. These results have implications for the siting of instrumentation in boundary layer wind tunnels where a major problem has been the location of the reference static pressure sensor. The static pressure field measurements give an indication of suitable locations and possible levels of error in past work.