Unstructured method for flows past bodies in general three-dimensional relative motion

A three-dimensional methodology was developed for unsteady flows past bodies that are in relative motion and where the trajectory of the motion was determined from the instantaneous aerodynamic field. This method coupled the equations of fluid flow and those of rigid-body dynamics and then captured the unsteady aerodynamic interference between the stationary and moving boundaries. The time-dependent, compressible Euler equations were solved on dynamic, unstructured meshes by an explicit, finite volume, and upwind method. The grid adaptation was performed within a window placed around a moving body, The Euler equations of dynamics were then solved by a Runge-Kutta integration scheme. The flow solver and the adaptation scheme were validated by simulating the transonic, unsteady flow around a wing undergoing a forced, periodic pitching motion and then comparing the results with the experimental data. Finally, the overall methodology was demonstrated by simulating the unsteady flowfield and the trajectory of a store dropped from a wing, The methodology, with its computational cost notwithstanding, has proven to be accurate, automated, easy for dynamic gridding, and relatively efficient for the required work hours.