Influence of pitching motion on subsonic wing rock of slender delta wings

A numerical simulation of the subsonic wing-rock phenomenon for slender delta wings is described. The present numerical model accounts for a second degree of freedom in pitch. According to the present simulation, there are two onset angles of attack: a, and a2, all initial disturbances lead to large-amplitude motions in both roll and pitch. The roll motion in this case differs markedly from the motion for a single degree of freedom. The present results suggest that the motion observed in the wind tunnel for the single-degree-of-freedom case differs significantly from the motion for the two-degree-of-freedom case. The numerical simulation of the wing-rock phenomenon for only one degree of freedom agrees very closely with two sets of experimental observations.