Abstract:

ESDU 74013 gives a method of predicting when the shock first appears downstream of the point of maximum cross section, either on first being formed or on moving from an upstream station. It has been observed experimentally that this condition corresponds to the rapid increase in shock-wave drag. The fins are taken into account as distributed cross-sectional area to give an equivalent body, and the method relies on computing an incompressible velocity distribution from the body geometry. Comparison of the method with experimental data shows it predicts the drag-rise Mach number to within 0.015.