Buildings in the wind

Abstract

AbstractSome of the problems arising from the flow of the wind about buildings are selectively illustrated in terms of the aerodynamics of vortex shedding and the interaction between a bluff body and turbulence in the approaching stream. Examples chosen draw attention to the spanwise incoherence of vortex shedding from a rigid body and vortex‐capture by an oscillating body, the effects of geometrical taper and shear in the undisturbed stream and the pecularities exhibited by the wakes behind porous windbreaks. Galloping oscillations of cables together with the large amplitude motions that can be engaged in by stranded electrical conductors are also briefly mentioned.As a preliminary to discussing the effect of turbulence on the flow past a body, as well as the distortion of the turbulence produced by the body, observations are offered on the relation between the known properties of the micro‐spectrum of atmospheric turbulence and wind tunnel measurements made in turbulent boundary layers. An interpretation of the latter in terms of the ‘inactive’ component of the unsteady motion near a surface, contributed by eddies in the outer parts of the boundary layer, suggests that further meteorological data, so frequently demanded by architects and aerodynamicists, may fail to add systematic information about the behaviour of the u‐component of the turbulent velocity other than is already available.Modern techniques of wind tunnel testing, which attempt to represent mean and turbulent properties of the wind, are described and cautionary remarks are made about the prospect for significant further refinement.