Exploring the drag reduction caused by a combined spike and jet setup for a hypersonic blunt object at low elevations

When hypersonic vehicles fly at low altitudes during the end of the trajectory, they often face extremely high dynamic pressure and greater resistance. Studying the drag reduction features of the hypersonic vehicle at low altitudes is highly important. The Reynolds-averaged N-S equations are solved using the finite-volume method with the SST k-ω turbulence model. Numerical simulations are conducted on three-dimensional hypersonic flow fields involving spike and combined spike and jet configurations at low altitudes with hypersonic speeds to investigate drag reduction effects and analyze flow field characteristics. The data indicates that the presence of a spike can effectively reduce drag during low-altitude hypersonic flight. Enhancing the spike length, its drag reduction efficiency first increases and then slightly decreases. Enhancing the Mach number, the length of the spike that achieves the best drag reduction efficiency becomes longer. A spike and jet combination can enhance drag reduction efficiency when flying at an angle of attack. Enhancing the spike length or the pressure ratio in this configuration can enhance its effectiveness in reducing drag. The findings of this study provide practical guidance for developing drag-reduction strategies for hypersonic aircraft flying at low altitudes.