## 1 Introduction
[13] discusses the characteristics of the water droplets' impact on NACA0012 type turbine. The Mach number is 0.3 and the turbulence model is the Spalart-Allmaras. Ref. [14] investigates the lattice dependence effect and the tone noise, which is calculated and the results demonstrate that the proposed approach is a cost-effective method for computing sound generation and propagation. Ref. [15] performs similar research. In summary, extant literature characterized by NACA0012 have mainly focused on the following aspects:  
* The influences of airfoil geometrical changes and attitudes on the external flow field properties, including temperature, temperature-related coefficients, force coefficients, and acoustic noise. * The aerodynamic characteristics of the turbines and special purpose airfoils, the shapes of which are similar to NACA0012 airfoils. * The investigation on related property prediction approaches. However, the abovementioned literature often adopts only one trailing edge shape and the trailing edge shape influence analysis on the aerodynamics prediction has been rarely explored, as only several papers underline. Ref. [16] investigates the aerodynamic characteristics through the blunt trailing edge modification, and with a shorter trailing edge, the shedding intensity decreases. However, it does not contain comparative research on the two trailing edge shapes. Ref. [17] analyzes he trailing edge shape influence on the force coefficients and the conclusions show that the angle of attack (AOA) and the Reynolds number (\(R_{e}\)) affect the trailing edge shape selection. Ref. [3] performs a further discussion under high \(R_{e}\) and the analysis shows that although the accuracy differences between the sharp trailing edge and the blunt trailing edge decreases as the AOA range increases; the former is preferred in all studied AOA ranges. But these papers are all discussed under the conditions of an incompressible environment. So far, we have not found reliable literature about trailing edge shape influence analysis under the compressible environment. In particular, the compressible environment property is affected by the Mach number and the typical Mach number of a hypersonic vehicle is often over five, but the maximum Mach number of the above simulations is lower than three, which means the choice criteria under hypersonic speed may be different. Moreover, there are different approaches to establishing the NACA0012 airfoil model while the above literature describes fewer details about them, and the related CFD simulation often adopts a fixed far-field distance and turbulence model. The discussions of these parameters on the numerical accuracy influence and the choice criteria are also inadequate. In this paper, we perform a detailed comparative analysis of different parameters on prediction accuracy under hypersonic speed. Appling three modeling approaches, six two-dimensional NACA0012 models comprising two trailing edge shapes are designed. Next, eighteen computational domains are established under 12 m/16 m/20 m far-field distances. The same number of structured grids is generated through a unified grid strategy and the appropriate numerical methods are confirmed by numerical comparison. According to the obtained CFD results, we conclude the internal relations among parameters, and the optimal configuration through comparative analysis with the reference data is determined. The analysis conclusions enrich the research of the compressible external flow field characterized by the NACA0012 under hypersonic speed. This manuscript is organized as follows: in Section 2 the adopted grid strategy and numerical methods are introduced and the corresponding CFD simulations are executed. Then, based on the numerical results, a detailed comparative analysis is carried out and the internal relations and the optimal parameters are confirmed through comparative analysis with the reference data in Section 3. Section 4 presents our conclusions.