Drag and heat reduction mechanism on a novel combination of spike and micro porous jet concept in supersonic/hypersonic flows

For blunt forebodies flying at supersonic/hypersonic Mach numbers, spike-based concept is widely adopted for simple implementation and economic among various drag and thermal reduction approaches. In this paper, numerical simulation on a mechanical spike attached to a blunt body with micro porous jet is carried out, and the compressible turbulent three-dimensional Navier-Stokes equations are solved with k-ω (SST) turbulence model to compute the typical flow field. The effectiveness of drag reduction and thermal protection is systematically evaluated across varying jet pressure ratios (PR) at different flight altitudes (H = 1 km, 10 km and 27 km) and freestream Mach numbers (Ma_∞ = 4.09, 4.77 and 5.15). When freestream conditions are taken to correspond to a flight speed of Ma = 6 and at an altitude of 27 km, the novel combination configuration with PR = 0.2 can provide drag and heat reduction effect on the spiked forebody by 61.3 % and 73.7 %, respectively. The physics behind the drag reduction and thermal protection associated with the composite configuration is presented with clarity. It is reported that the aerodynamic drag over the spiked blunt model is decreased with rising mass flow rate, and this performance is qualitatively similar for all Mach numbers. Considering that the total drag force increases continuously at large PR and exceeds that with low PR, this study also portrays the necessity of taking the additional jet drag into consideration while comparing the total drag force for different cases.