NUMERICAL-SIMULATION OF FORCED AND FREE-TO-ROLL DELTA-WING MOTIONS

The three-dimensional, Reynolds-averaged, Navier-Stokes (RANS) equatio ns are used to numerically simulate nonsteady vortical flow about a 65 -deg sweep delta wing at 30-deg angle of attack, Two large-amplitude, high-rate, forced-roll motions, and a damped free-to-roll motion are p resented, The free-to-roll motion is computed by coupling the time-dep endent RANS equations to the flight dynamic equation of motion. The co mputed results are in good agreement with the forces, moments, and rol l-angle time histories. Vortex breakdown is present in each case. Sign ificant time lags in the vortex breakdown motions relative to the body motions strongly influence the dynamic forces and moments.