Turbulent boundary layers in blast wave and shock tube flows /

Abstract

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)."August 1976."Includes bibliographic references (pages 53-54).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).RDT & E Project no. ;Mode of access: Internet