VARIOUS SOURCES OF WING ROCK

Limit cycle oscillations in roll of advanced aircraft can result from three different fluid mechanical flow processes. The so-called slender wing rock is caused by asymmetric vortex shedding from highly swept wing leading edges. A completely different flow mechanism causes wing rock for aircraft with moderately swept leading edges. In this case, the causative mechanism is dynamic airfoil stall. Finally, if the aircraft has a slender forebody, the rocking motion can be generated by asymmetric body vortices from the nose, which interact with a nonaxisymmetric aft body, e.g., due to the presence of wing or tail surfaces. This paper describes the nonsteady fluid dynamic processes generating the different types of wing rock. © 1990 by L. E. Ericsson.