Analysis of flowfield characteristics for equal polygon opposing jet on different freeflow conditions

Drag and heat flux reduction efficiency induced by the equal polygon opposing jet could be higher than the one issuing from conventional circular orifice. The two-equation SST k-w turbulence model has been utilized to study the detailed information of flow field, and the numerical method has been validated against the available experimental data in the open literature. At last, the effects of angle of attack (α), angle of sideslip (β) and angle of jet flow (δ) on the aerodynamic characteristics have been investigated numerically in the current study. The obtained results show that the drag force increases with a higher absolute value of α and the Stanton number (St) reaches its maximum when α=−10°. Moreover, the peak St appears when α=5°. The influence of β on drag reduction shows similarity with that of α, and the maximum Cc appears when |β|=10°. More severe aero-heating occurs on the upper surface when |α| or |β| changes from 0° to 15°. The δ can reduce the maximum heat flux (Qmax) in the whole flow field and improve the thermal protection characteristics. The Qmax can reduce 22.5% and 9.3% at most when δ is −5° and 5° respectively.