Numerical simulation of circular cylinders and wing sections in unsteady motion

For most of the published research considering separation control for wing sections the effect of wing motion on the fluid dynamics is neglected. In the near-stall and/or full stall regime, where separation control is of interest, some degree of wing movement is always present. Additional terms were added to a compressible Navier-Stokes code to allow for simulations of wing sections undergoing structural motion. Several circular cylinder and wing section validation cases from the literature were considered: Good agreement with earlier published results was obtained for a circular cylinder undergoing a forced and a flow-induced plunge motion. In addition, the interaction of a neutrally buoyant cylinder with a vortex pair was investigated. Simulations were also carried out for a NACA0012 wing section undergoing a harmonic pitching motion and plunging motion. For a plunging motion with a reduced frequency of k=12.3 the unsteady fluid dynamics were found to depend strongly on the freestream Mach number for 0.1≤M≤0.4. Finally, simulations for a NACA64₃-618 wing section illustrated that the flow field can “lock in” to a high-frequency harmonic pitching motion.