Wake of Elongated Low-Rise Building at Oblique Incidences

Abstract

We investigated the turbulent wake of an elongated low-rise building at oblique wind incidence via wind tunnel experiments and numerical simulations. The deflection phenomenon of mean building wake is clearly supported by the downwind trajectory of the point of maximum velocity deficit. A two-step mechanism is proposed for the understanding of the wake deflection process and its evolution in the building wake. The oblique wind incidence leads to a location shift of shear layer flow competition in the near-wake region (“WD1”) and then the deflected prevailing wind extends its effect in the far-wake region (“WD2”). The streamwise development of lateral wake deflection predicted from this mechanism, as well as the variations with height due to the three-dimensional wake structure, compares well with the measurement and simulation results. For aviation safety assessment of wake effect of the present building on aircraft landing, the data are compared to the “1:35 rule” and “7-knot criterion”. In addition, the importance of velocity fluctuation is demonstrated with an exceedance probability analysis.