Aerodynamic Shape Optimization Of Loitering Missile Based On Discrete Adjoint Method

Loitering missile is a kind of new weapon,which has both characteristics of missile and unmanned aerial vehicle,so it is usually with complicated shape.To achieve better flight performance,aerodynamic shape design is of great importance.For this reason,research on aerodynamic shape optimization of loitering missile is significant in the development of loitering missile.Aerodynamic shape optimization based on traditional CFD method is usually of large amount of calculation.This paper conducted a research on aerodynamic shape optimization design method based on discrete adjoint method.Adjoint equation is established,and the solution is deduced.An aerodynamic shape optimization system is constructed based on computation and analysis of flow field、 calculation of discrete adjoint equation and aerodynamic shape parameterization method using FFD technology.An example of inverse design is given to verify the feasibility of the shape optimization method.The flow field of two-dimensional airfoil and three-dimensional missile wing is calculates using numerical simulation method.Different situations whose angle of attack is of 0 °-16 ° has been studied respectively.The lift coefficient 、 drag coefficient and lift-to-drag ratio are analyzed to support aerodynamic analysis and shape optimization.Aerodynamic shape optimization of two-dimensional airfoil is achieved.Restrain the thickness of airfoil and improve the lift-to-drag ratio.The lift coefficient of optimized airfoil has been increased by 68.33% at the angle of attack of 0°。 The lift-to-drag ratio has been increased by 123.69%,and the increase speed decreases gradually with the increasing angle of attack.The lift-to-drag ratio of optimized airfoil is less than that of initial airfoil when the angle of attack reaches 12°.The stalling angle of attack of optimized airfoil is smaller,and better aerodynamic performance will be provided under the small angle of attack.Aerodynamic shape optimization of missile wing of loitering missile is achieved.Restrain the volume of missile wing and achieve drag reduction.Drag coefficient is reduced by 27.24% the angle of attack of 0°.The lift coefficient、 drag coefficient and lift-to-drag ratio of optimized loitering missile、loitering missile with optimized airfoil and initial loitering missile has been compared.The lift coefficient of loitering missile with optimized airfoil is the biggest of all,the drag coefficient is smaller and the lift-to-drag ratio is the biggest at small angle of attack.The stalling angle of attack is kind of small,and the aerodynamic performance is poorer at large angle of attack.The lift coefficient of optimized loitering missile is just the same as that of initial missile,and the drag coefficient is the smallest.The lift-to-drag ratio is larger than that of initial missile,but less than that of loitering missile with optimized airfoil at small angle of attack.The stalling angle of attack of optimized loitering missile is relatively large,and the aerodynamic performance is better at large angle of attack.This paper has the reference value in practical application of aerodynamic shape design of loitering missile.