Numerical Simulation of Pulsed Blowing Coanda-Jet Flow Control for a Wing Section

Large-eddy simulations are carried out to describe the subsonic flow over a wing section, using pulsed blowing Coanda-jet circulation control to augment lift. The section geometry consists of a modified supercritical airfoil, with a quarter-circular trailing-edge Coanda sur- face. Because the configuration does not include a slotted trailing-edge flap, the mechanical complexity and weight may be reduced. The configuration corresponds to an experimental investigation, that provided limited measured data. High-fidelity solutions are obtained to the unsteady three-dimensional Navier-Stokes equations, at a chord-based Reynolds of 475,000, a freestream Mach number of 0.1, and angle of attack equal to 5.0 deg. As a means of decreasing mass-flow requirements, pulsed blowing is supplied to a jet flowing over a trailing edge Coanda surface. Parametric studies are performed for the pulsing frequency and duty cycle. Results are compared among the various cases, and with previous steady-jet simulations. Adverse effects of low-frequency pulsing are uncovered, and an optimal frequency is identified. Features of the time-mean and instantaneous flowfields are characterized.