Particle Temperature and Mach Number Effects on Drag Coefficient in Shock-Particle Interaction

In this study, the effects of particle temperature and Mach number on the drag coefficient in shock-particle interaction were investigated by direct numerical simulations of three-dimensional compressible Navier–Stokes equations. Axisymmetric simulations were mainly conducted, while three-dimensional simulations were employed for validation.

The particle Reynolds number based on quantities behind the shock was set to 200 or 300, the particle temperature and the Mach number were varied. The isothermal condition or adiabatic condition was imposed on the particle surface.

The results of three-dimensional simulation showed that evaluation of the drag coefficient using axisymmetric simulations is appropriate. The results of axisymmetric simulations showed that the viscous drag coefficient increases with higher particle temperature. In contrast, the pressure drag coefficient is almost independent of particle temperature. It was also found that Mach number affects both the viscous and pressure drag coefficient. The peak value of total drag is almost insensitive to particle temperature since the pressure drag is dominant. At later phase, the contribution of viscous component increases significant relative to the peak value, leading to a tendency for the total drag coefficient to increase with higher particle temperatures.

The effects of particle temperature and Mach number obtained in this study are expected to contribute to the development of flow models for shock-particle interaction.