Turbulent Boundary Layers in Blast Wave and Shock Tube Flows.

An unsteady boundary layer if formed along the ground as a result of nuclear explosions and large HE bursts. This boundary layer influences overturning vulnerability predictions for combat vehicles subjected to blast loading. An integral boundary-layer theory is used to predict the growth of the turbulent boundary layer behind a blast wave. Predictions are presented for conventional and nuclear yields ranging from 18100 kg 20 ton to 9.07 x 10 to the 8th power kg 1 Mton TNT equivalent. The boundary-layer growth is calculated using two techniques and compared with experimental boundary-layer measurements taken in a 90700 kg 100 ton TNT surface tangent sphere explosion. One of the techniques, based on experimentally-derived values for shock position and velocity appears to give a reasonable estimate of the boundary-layer thickness based on the limited experimental data available for comparison. Shock tube simulation of blast wave boundary-layer effects is discussed. Estimates are presented for the growth of the wall boundary layer in the BRL 2.44m 8 ft shock tube and the boundary layer that can be formed on a ground plane mounted in this shock tube. Testing in the wall boundary layer is not feasible because of balance response-time restrictions. It appears that blast wave boundary layers of moderate thickness, on the order of a meter or less can be simulated using the shock tube ground plane boundary layer. Author