Effect of spike geometry on hemispherical blunt body

Abstract

The major challenge in aerodynamics is the reduction of drag for high-speed vehicles. Re-entry vehicles usually travel at hypersonic speeds, because of this, they experience high temperature and drag force. One of the ways to reduce the heating and coefficient of drag is by using spike. In the present study we have numerically investigated the aerodynamic performances of a blunt body with sharp spike and hemispherical spike with different length to base diameter ratio using ANSYS fluent. We have compared the performance of the bunt body with and without spike. Density based solver and explicit method have been used as it is most preferred for high-speed flows. Simulations have been carried out at three different Mach numbers 4, 5 and 6. Effect of semi vertex angle of the sharp spike is also studied. Results are validated with the available literature. It is observed that drag coefficient increases with increase in Mach number, semi vertex angle and decreases with increase in L/D ratio. It was also found that both drag coefficient and Heat flux were minimum for hemispherical spike when compared to others.