Flow Characteristics over a Missile at Higher Angle of Attacks Using Experiments and Simulation

The need to determine forces and moments acting on bodies of revolution at high angles of attack originally arose in connection with airships. In general missile aerodynamics is dominated with vertical and separated flows. The advent of highly manoeuvrable missile design concepts has required a major effort in understanding the problem of slender bodies of revolution at high angles of attack. An extensive experimental investigation was conducted to determine the aerodynamic forces and moments. The aerodynamic data are needed to establish the structural and control system requirements. Tests were conducted on a smooth missile model with several interchangeable nose parts in a wind tunnel at subsonic level at high angle of attack. The yaw moments and side forces are determined using force measuring systems by which maximum induced side force was found. Using oil flow visualization technique, vortex shedding location and vortex strength were traced at various angles of attack. Computational analysis was carried out for the cone, elliptical and ogive nose shapes. It is then compared with the experimental results to know where the least flow separation occurs and proper reasons for the side forces.