Measurements of the forces and moments generated by swept-back grid fins

Abstract

A swept-back grid-fin with sharp leading edges was proposed in previous studies for reducing the drag associated to the choking of the flow in the lattice cells at transonic speeds. Viscous computational fluid dynamic simulations and experimental measurements at transonic and supersonic speeds and zero angle of attack indicated a 30% drag reduction compared to a standard grid-fin type. The current follow-on study presents additional windtunnel measurements performed at selected freestream conditions by varying the angle of attack of the ogive-cylinder body used to support the grid fins. The results provide information on the control authority of the grid fins and indicate that the swept-back with sharp leading edges type has equal or better control characteristics than the standard type. © 2012 by Temasek Laboratories - National University of Singapore.