Numerical Simulation of Flow over an Axisymmetric body in Free Flight

Flow field around a projectile after thrust has been stopped and in inertia flight is studied numerically by a finite difference scheme. This study aims at clarifying the mechanism of free flight, which is generated and developed by rotation of body and gravity. Among two types of projectiles concerned a three-dimensional flow around the slender body, such as aircraft body, rocket .causes drastic variation with high angle of attack and has considerable influence on the aerodynamic behavior. The flow over a paraboloidal-nose cylinder at pitching rotation is considered with inertia translating motion and the flow symmetry assumption . Another example is a oblate spheroid, and in these examples the initial condition is the flow at steady \u91flight\u92. In present numerical study coordinate system fixed on the body ,with non-inertial frame of reference, which yields additional terms in Navier Stokes equation. The dual-time pseudo compressibility code is applied for incompressible flow. The Newton\u92s 2nd law is used with the balance of aerodynamic force and gravity together with angular momentum equation. For the slender body the initial incidence angle is horizontal or 40deg. For the spheroid the initial motion is set either upwardi: counter to gravity-direction or downward one. For Reynolds numbers lower than 10000, the behavior of flow field and varying incidence angle will be discussed as well asthe trajectory of body