Viscous flow calculations of shock diffraction and drag loads on arched structures

The goal of this work is to develop a numerical method for computing both the shock diffraction phase and viscous drag phase of airblast loading on structures. Calculations of single Mach reflection and double Mach reflection demonstrate the accuracy of the numerial method for oblique shock reflections. A long-term calculation of blast loading on a structure demonstrates that the drag coefficient becomes zero if viscosity is neglectd. When the calculation is repeated with viscous effects included, the flow separates and a finite drag coefficient is obtained. We conclude that meaningful long-duration blast loading calculations are possible.