An approximate method for calculating the pressure wave ahead of an impulsively started blunt-nosed axisymmetric body of arbitrary and variable nose radius and velocity is described. The method is then used to calculate the pressure wave ahead of the spray dome and water plume from 1-lb explosions at depths from 0.3 to 0.6 feet. Agreement with experimental data is good. The results demonstrate that taking the outer contour of the spray dome and water plume as an impervious surface displacing the air is a practicable boundary condition for air wave calculations. They also demonstrate the dominance of the plume motion in producing airblast, at the shallow end of the above depth range.
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