Combined effects of double flat aerodisks and rear opposing jets on hypersonic spiked blunt body drag and heat reduction: An uncertainty and sensitivity analysis

This study numerically investigates the combined effects of double flat aerodisks and rear opposing jets on the drag and heat reduction performance of a hypersonic spiked blunt body. Uncertainty quantification and sensitivity analysis are performed using the Non-Intrusive Polynomial Chaos (NIPC) method and Sobol indices. The results show that the double flat aerodisk design with rear opposing jets outperforms the single-disk configuration, reducing the peak surface pressure by 54% and maximum temperature by 34.7% on the blunt body. The opposing jet weakens the reattachment shock wave, while the jet gas flows downstream and effectively covers the blunt body wall, isolating it from direct contact with the high-temperature incoming flow, thereby providing efficient thermal protection. Uncertainty analysis reveals that the uncertainty in surface pressure distribution is consistently higher than that of temperature distribution, with uncertainties exceeding 30% in most regions for both pressure and temperature. Sensitivity analysis indicates that the spacing between aerodisks l/L and the radius of the rear aerodisk R 2 dominate the uncertainty in pressure distribution, whereas the uncertainty in temperature distribution is almost entirely governed by the jet pressure ratio PR , which exhibits a negative correlation. Additionally, the sensitivity of the drag coefficient to variations in input parameters is relatively uniform.