Investigation of Roll Pitch Yaw Phenomena for a Finned Store Released from a Wing

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. The three-dimensional, unsteady Navier-Stokes equations and k-epsilon 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 Mach number and ejector force applied on the store are carried out to investigate the unsteady roll, pitch and yaw phenomena of the separated store. The maximum value of pitch rate of the store decreases as the Mach number increases, and time of maximum value of yaw rate shortens as well. Both roll and yaw rates decrease as the ejector force applied on the store increases, and time of maximum value of roll, pitch and yaw rates shortens as well.