The Aerodynamic Shape Design And Aerodynamic Characteristics Analysis Of Non-parachute Terminal Sensing Ammunition

In the thesis, the aerodynamic shapes and characteristics of non-parachute terminal sensing ammunition (TSA) were studied. The aerodynamic shapes of non-parachute TSA were designed; the wind tunnel force experiments and rotation speed measurement were conducted; the grid generation methods of the flow field around the complicated figuration of projectiles were studied; the programs of the flow field around the low speed projectile were developed. The flow field around the non-parachute TSA was numerically simulated and the aerodynamics of the shapes are obtained. Based on the results, the aerodynamic shapes of the TSA were improved.Firstly, the principle of the aerodynamic shape design of the non-parachute TSA was proposed. The basic aerodynamic shapes and characteristics of the body and the tail wings of the TSA were studied and the aerodynamic shapes of the projectile body and tail wings were chosen. Based on the blunt short cylinder, both lengthways-folded and radial-folded tail fins were designed, and the distribution of wings was also studied. Based on the flat short cylinder, the double lengthways-folded wings were designed. The coordinate systems about the asymmetric double-wing non-parachute TSA were built based on which the aerodynamic forces are defined. The criterion of the stabilization of the scanning angle of the double-wing TSA was given, and the integral expressions of the aerodynamic forces were proposed.Secondly, wind tunnel experimental models of the non-parachute TSA were designed and low speed wind tunnel experiments were carried out from which the aerodynamic force data of models both fixed and rotating were obtained and the rotation speed was measured. Through the experiment, the aerodynamic characteristics of the model were grasped, and the direction of choosing and improving the aerodynamic shape is clear.Thirdly, the numerical methods of the flow filed around the non-parachute TSA were studied, and the entire method about the generation of the flow field grid around the projectiles were developed. With the low-speed preconditioning method, the multigrid method and the parallel algorithm as the core, the reliable and efficient solver was written. The numerical methods can be used in the aerodynamic calculation of the non-parachute TSA and in the flow field numerical simulation of other projectiles.Fourthly, based on the established numerical methods, the flow field and the aerodynamics of the non-parachute TSA were calculated, and the flow field and the aerodynamic characteristics were analyzed. Based on the shape of the wind tunnel model, the grids of the flow field around the four-and triple-wing TSA were respectively generated. The flow field was numerical calculated, and thus, the longitudinal aerodynamic coefficients were obtained. The pressure coefficient along the axial of cylindrical part of the projectile and the chordwise and spanwise of the tail wing was analyzed and was compared with the pressure coefficient along single body and wings. The rule of the aerodynamics variation with the deflection angle of the wing was obtained.The flow field and the aerodynamic forces of the remodeled shape of the double-wing non-parachute TSA based on the wind tunnel experiment were calculated, which shows that the static stability of the remodeled shape was improved. The flow in the chord section of the wing was studied. Through the analysis and contrast of the pressure distribution along the chord with and without the little wing, the method of improving the static stability of the double-wing non-parachute TSA was raised, and the rolling damping of the little wing was proved.