This paper focuses on the laminar interaction of shock waves and the phenomenon of steady/unsteady flow in the hypersonic double wedge flow. The different working conditions (Ma_∞ and Re) were selected for numerical simulation and flow characteristics research with the developed third-order WENO scheme; The variation patterns of shock wave structure and separation zone in steady/unsteady flow fields caused by parameter changes were summarized. Based on the least squares support vector machine (LS-SVM) model, we developed a steady/unsteady flow states prediction model for the double wedge flow using various kernel functions (linear, polynomial, and radial basis functions) in order to forecast the steady/unsteady flow states of the double wedge flow at various Ma_∞ and Re. Three prediction models were validated and evaluated on the validation set. With 16 working circumstances, the results demonstrate that the radial basis function prediction model is capable of successfully predicting every double wedge flow state. The accuracy and true positive rate of the prediction results are 1, and the false positive rate is 0. The prediction ability is the strongest and has better generalization ability. The polynomial kernel prediction model takes second place in prediction ability, and the linear kernel prediction model has the worst prediction ability.

In view of the friction and heat flux prediction problems in the hypersonic flows around a lift body, the influence of different gas models (perfect gas and equilibrium gas), slip boundary models (M-S and Le), and incoming flow conditions (height, Mach number, and wall temperature) on the prediction of friction and heat flux was studied with the developed third-order weighted essentially non-oscillatory scheme. Firstly, numerical simulation and analysis of double Mach reflection problem and typical hypersonic examples were carried out by different slip boundary models and gas models. The results show that high-fidelity gas models, slip boundary models, and high-precision schemes show better accuracy in the calculation of hypersonic problems. On this basis, numerical simulation and analysis of hypersonic flows around a lift body at different heights, Mach numbers, and wall temperatures are carried out. The effects of slip boundary models and gas models on the prediction of friction and heat flux are comprehensively analyzed. The results show that different gas models are quite different, and the equilibrium gas model gets lower temperature in the boundary layer, smaller thickness of the boundary layer, greater wall heat flux, and slightly larger friction coefficient and total drag coefficient. The difference between the two gas models increases with the increase in height. Under the perfect gas model, the total drag coefficient, position of the center of pressure, and heat flux distribution of different slip boundary models show greater difference, which increases with the increase in height. Under the equilibrium gas model, the results of different slip boundary models are similar.