## 1 Introduction  
The flight environment of hypersonic vehicles is becoming more and more severe, and the issue of environmental adaptability is more important. Through viscous retardation or shock wave compression, the high-speed flow would be slowed down and the gas pressure and temperature increase sharply. The resulting high temperature and pressure environment would cause vehicle ablation and the internal equipment to fail. NASA counts the causes of previous space launch crashes with environmental failures taking the top spot. As a result, accurate aerodynamic environment prediction plays a vital role in designing and optimizing the vehicle [1, 2]. The engineering estimation method, wind experiment, and computational fluid dynamics (CFD) methods are the three general approaches for environmental predictions. The first two methods have the disadvantages of a time consumption, high costs, and limited prediction accuracy. With the development of computer technology, the CFD method has become the primary method in the prediction study [3, 4]. NACA0012 is a typically used airfoil for research on the properties of the external flow field, which is developed by the National Advisory Committee for Aeronautics (NACA). In order to perform aerodynamic environment predictions based on NACA0012 during the flight [5], we need to perform a parameter analysis on calculation accuracy to confirm the optimal simulation configuration. A different flow speed implies different external flow field characteristics, and the corresponding prediction parameters should be specifically confirmed. According to the flow speed, the external flow field is divided into incompressible and compressible. Further, for the compressible external flow field, when the Mach number is lower than one, it is at the transonic speed. When the Mach number is between one and three, it is at the supersonic speed. When the Mach number is between three and five, it is at the high supersonic speed. When the Mach number is over five, it is at the hypersonic speed. The parameter influence analysis of the incompressible external flow field characterized by NACA0012 airfoil under low speed is discussed in another paper by [PERSON] and [PERSON] [3]. During the flight path, the vehicle is mainly at hypersonic speed. Therefore, in this paper, we study the parameter influence on the compressible external flow field prediction at hypersonic speed. Ref. [5] applies the k-epsilon, SST k-omega, and Spalart-Allmaras (SA) three RANS turbulence models to perform CFD prediction on NACA0012 force coefficients, and the results demonstrate that the numerical simulation data are in suitable agreement with the published data. In Refs. [6; 7], the grid strategies for the around NACA0012 turbulence flow are discussed, and the conclusions indicate that the trailing edge shape is a key factor affecting the accuracy. NACA0012 has the sharp trailing edge and the blunt trailing edge of two shapes. In terms of the sharp trailing edge, Refs. [8; 9] adopt the Mach numbers from 1.7 to 2.7 and the turbulence models of SST k-omega and SA to discuss the external flow field property influenced by the geometrical changes, including dimpled and square dimpled NACA0012s. The results demonstrate that the environment temperature increases with the Mach and vice versa. Ref. [10] performs similar research, in which the upper and lower surface temperatures are all investigated. Ref. [11] selects the SST and SA to study the heat effect on the force coefficients. Because of the temperature difference between the extrados and intrados of the airfoil, the drag coefficient declines and the lift coefficient is raised. In Ref. [12], under the conditions of a static, plunging, and pitching NACA0012, the heat transfer effect on the aerodynamic performance, with particular emphasis upon the force coefficients, is discussed. Through a spectral analysis, the force coefficient amplitudes decrease while the surface temperature increases. Ref.