Determination of Wing-Only Aircraft Tumbling Characteristics Through Computational Fluid Dynamics

Wing-only aircraft configurations are susceptible to a flight instability called tumbling. Tumbling involves an autorotative pitching motion, primarily about an axis parallel to the aircraft's lateral axis, combined with planar translation. Tumbling is the suspected cause of a wing-only aircraft (Northrop YB-49) crash in the late 1940s and is a potential problem for future wing-only and blended-wing-body aircraft configurations. It may be difficult, if not impossible, for a wing-only aircraft to escape the tumbling motion once it develops. It is therefore important for aircraft designers to understand the causes of tumbling to prevent its onset Tumbling has been demonstrated in qualitative free-flight wind-tunnel experiments, but few have attempted to quantify the motion using computational fluid dynamics. The purpose of this research is to use computational fluid dynamics to study the tumbling characteristics of a wing-only aircraft. Specifically, the effects of initial conditions, degrees of freedom, Reynolds number, and aircraft static margin will be investigated.