Turbulent Study of Roll Pitch Yaw Phenomena for a Finned Store Released from a Wing Regarding Different Values of Angle of Attack

In this article, the commercial software CFD FASTRAN is applied to study the roll, pitch and yaw phenomena of turbulent flows around a finned store released from a wing regarding different values of angle of attack. The three-dimensional, unsteady Navier-Stokes equations and standard k-ɛ turbulent model are solved in the Cartesian coordinate system. The Chimera two-block grid system is utilized, and grid communication among two blocks are automatically implemented. To evaluate the accuracy of the present calculation, the calculated instantaneous trajectories of center of gravity of store, angles of roll, pitch and yaw, velocities and angular rates are compared with those of experimental data. The satisfactory agreement is achieved. Then, computations of different values of angle of attack applied on the store are carried out to investigate the unsteady roll, pitch and yaw phenomena of the separated store. Longitudinally clockwise roll angle of store from pilot's viewpoint and yaw angle toward the wing tip decrease as the angle of attack increases. Maximum value of pitch angle increases as the angle of attack increases, and the time of maximum value of pitch angle increases as well.