Characterization of Jet Flow From a Decaying Wave Blast Simulator.

A computational study was performed to characterize the time-dependent jet flow exiting the expansion tunnel of the large blastthermal simulator LBTS. The aerodynamic environment produced by the jet flow has been identified as a possible means of testing full scale military equipment in high drag blast events. Two-dimensional 2-D axisymmetric calculations were used to estimate the peak pressure, velocity, and impulse levels in the jet flow as a function of the initial conditions. Next, a set of 2-D planar symmetry calculations was performed to assess the effect of the ground plane on the flow field and determine the changes in flow parameters as a function of distance from the exit plane. Finally, a set of three-dimensional 3-D calculations was used to generate a detailed description of the time-dependent flow and to determine its spatial uniformity for vehicle testing. The 3-D calculation simulating the maximum operational limit of the facility resulted in a peak flow velocity of approximately 420 ms in an event with a duration of approximately 1.2 s.