Abstract |
Direct measurements of the drag of two- and three-dimensional obstacles in linearly stratified fluid are compared with the implications of inviscid, unsteady theory and with the few similar measurements already available in the literature. Attention is concentrated on obstacles which generate separated wakes and it is shown that prior to the appearance of stationary lee waves the stratification always leads to a drag reduction whose magnitude increases with the spanwise width of the obstacle. Once the stratification increases to the point where a stationary lee wave exists the drag rises again, but usually falls thereafter whenever an integral value of the parameter, K, is approached. |