Parallel CFD computations of projectile aerodynamics with a flow control mechanism

This paper describes a computational study undertaken to model the free-flight aerodynamics of a finned projectile both with and without flow control. The flow control is achieved by locating small microflaps between rear fins of the finned projectile. These microflaps alter the flow field in the finned region of the projectile resulting in asymmetric pressure distribution and thus, producing control forces and moments. Both steady-state computational fluid dynamics (CFD) and coupled CFD/rigid body dynamics (RBD) techniques have been used to compute the aerodynamics associated with the free flight of the finned projectile both with and without the microflaps. Some results relating to the parallel performance of the CFD flow solver are also addressed. Navier-Stokes computations have been performed and steady-state solutions have been obtained from subsonic to supersonic speeds. Computed results show the microflaps to be ineffective at transonic speeds and effective at supersonic velocities. Based on these results, additional coupled CFD/RBD calculations were performed at three supersonic velocities (M = 2.0, 2.5, and 3.0). Computed results obtained from these coupled virtual fly-out simulations include the effect of microflaps and are being used to show the potential of these microflaps for providing control authority to maneuver the finned projectile.