Summary

ESDU 74036 is based on correlations of experimental results obtained on a plate at zero incidence, for predicting the increment in drag for Mach numbers less than 3. The methods apply to a cavity with sharp edges, walls normal to the plate, flat bottom and no through-flow; no information is available on rounding or chamfering of the corners, but such edge modifications should not be assumed to be beneficial. The depth/diameter ratio varied from 0.04 to 1.5 but a method of dealing with a cavity in which the ratio is less than 0.04 and based on the method of ESDU 75031 is presented. The data apply strictly in zero pressure gradient flows, but guidance on their use where there is a pressure gradient is given in the Data Item.