Abstract:

ESDU 80024 provides information about the effects of blockage on the forces and pressures on, and flow around, bluff and quasi-streamlined bodies in two- and three-dimensional flows confined by straight, solid-wall boundaries. The data apply to blockage up to about 20 per cent of area. Sources of information are also given for open jet wind-tunnels where blockage corrections may be equally important. A description is given of the effects of blockage on bodies of all shapes and recommended correction methods are given for mean force and pressure measurements together with tabulated data needed to apply the methods to a range of body shapes. The reference flow properties appropriate to both uniform and shear flows are considered. The data include guidance on the application of blockage corrections to estimating forces on, and pressure drop across, bodies in ducts. Appendices give further background information on the methods recommended, sketch out less important bluff-body blockage corrections and discuss practical problems of wind-tunnel testing for blockage effects.