## 1 Introduction  
The quality of aerodynamic characteristics parameters has a direct impact on the maneuverability, flight stability, and control accuracy of the projectile. It is therefore one of the key technical parameters that must be given due consideration in the development and use of projectiles. With the increasingly demanding requirements of modern projectiles for high maneuverability and high angles of attack flight performance, the efficient and accurate evaluation of projectile aerodynamic characteristics is becoming increasingly important, especially under the high angle of attack flight conditions. The nonlinearity of aerodynamic calculations for projectile is high, and modeling and simulation are difficult. Small variations in flight conditions and structural parameters, etc., may cause large deviations in aerodynamic responses. Taking a small cylindrical projectile as an example, and to realize its attitude control, it is necessary to conduct aerodynamic characteristics analysis on it and analyze the main influencing factors of its aerodynamic characteristics parameters. Many scholars have carried out a lot of research on the numerical simulation of aerodynamic characteristics regarding rotating bodies, especially blunt cylinders, and have discussed the problems of static aerodynamics, asymmetric separation eddy, and pitch dynamic stability derivatives in the state of different angles of attack [1; 2; 3; 4; 5; 6; 7; 8; 9]. [PERSON] (1982) solved the three-dimensional flow field of a supersonic pointed arched spiral at an angle of attack of 20\({}^{\circ}\), and obtained a vortex structure on the leeward side of the spinning body [1]. [PERSON] (2006) used the realizable k-\(\varepsilon\) model to study the separation of the flow on the leeward side of the pointed slender spiral under a medium and large angle of attack at supersonic speeds [4]. [PERSON] (2005) used the three-dimensional N-S equation to calculate the change process of the elongated spiral from the symmetrical flow with the small angle of attack to the asymmetric flow with the large angle of attack, and gave the characteristics of the vortex structure and physical quantity distribution before and after the change [5]. [PERSON] (2021) used the SST k-\(\omega\) turbulence model to solve the three-dimensional N-S equation based on the finite volume method, and analyzed the variation of the flow field around the projectile and the lateral force under different angles of attack [9]. In particular, the effects of boundary conditions and the flow angle relative to the axis of a cylindrical object on vortex shedding and flow patterns have been studied [10; 11; 12; 13]. [PERSON] [14] analyzed the pressure distribution on the surface of a hemispherical cylindrical model at low Reynolds numbers and different angles of attack, and pointed out the effect of the separation phenomenon on the downstream development of asymmetric separating vortices at the top and back wind surfaces of the model. In order to determine the main parameters affecting the aerodynamic characteristics of the cylinder, the sensitivity analysis of the aerodynamic characteristics at different angles of attack states is needed. A lot of sensitivity analysis methods have been proposed. Among them, the global sensitivity analysis (GSA) method can extend the input parameter range to the whole domain, without the limitation of the linear model, so it can study the nonlinear aerodynamic characteristics analysis problem [15; 16; 17; 18; 19; 20; 21]. The Sobol method is a GSA method based on variance decomposition, and can conveniently quantify the input parameters, the coupling between parameters, and the effects of the group input factors on the model outputs [19; 20; 21]. However, the computational time for single-sample analysis of the aerodynamic performance is quite long, which will result in the computational cost of the Sobol method being quite high. Therefore, it is necessary to improve the solution efficiency of Sobol sensitivity analysis.