Wind flow over the low-rise building models with gabled roofs having different pitch angles

In this study, the turbulent flow fields on the low-rise building models with gabled roofs having different pitch angles immersed in atmospheric boundary layer have been investigated experimentally and numerically. The models of the Belgian Building Research Institute (BBRI) test building with a scale of 1:100 were studied with 15 degrees, 30 degrees and 45 degrees roof pitches for the wind direction of 90 degrees. Flow visualization, measurements of velocity and surface pressure around the models placed in wind tunnel were made. 3D solutions of the flow fields were obtained with two different turbulence models. The mean velocity and turbulence kinetic energy profiles are influenced by the roof pitch. Recirculation regions occur on the leeward part of roofs and at the behind of the models due to flow separation. These regions are much stronger and spread up to the roof ridge with increasing roof pitch. Largest values of turbulence kinetic energy for entire flow field occur at height of the roof level and they prove the presence of the mixing layer between the free stream flow and reverse flow region. It is seen from the surface mean pressure distributions that the 15 degrees roof pitch causes more critical suction on the roofs than those of the 30 degrees and 45 degrees roof pitches. The numerical results shows that Realizable k-epsilon turbulence model exhibit better agreement at the prediction mean velocity and turbulence kinetic energy while Standard k-omega turbulence models exhibit better agreement at the prediction of mean pressures coefficients. (C) 2015 Elsevier Ltd. All rights reserved.