Incident and Normally Reflected Overpressure and Impulse for Detonations of Spherical High Explosives in Free Air

Air-blast parameters, including incident and reflected peak overpressures and impulses, and shock-front arrival times, are typically estimated for protective design using charts developed by Kingery and Bulmash. The charts underpredict incident and normally reflected peak overpressures and incident impulse near the face of the charge. Numerical analyses of detonations of spherical charges of trinitrotoluene in free air are performed using a verified and validated computational fluid dynamics (CFD) code to understand the shortcomings of current approaches for calculating incident and normally reflected overpressures and impulses, and for shock-front arrival time. New equations and design charts are proposed based on CFD calculations.