A reduced-order, unsteady aerodynamic model for deployable Gurney flaps is formulated based on indicial concepts. The model is developed in the time domain to ensure applicability to arbitrary deployments. It takes into account compressibility effects as well as the nonlinear aerodynamic effectiveness of Gurney flaps with respect to their height. The model can be used to predict the aerodynamics of Gurney flaps that are positioned either upstream or at the trailing edge of the airfoil. Upstream Gurney flaps have been shown to be more complex to model because of the formation and convection of lower-surface vortices following their deployment. These vortical disturbances can introduce nonharmonic components in the aerodynamic response, substantially affecting the loads and complicating the analysis. The adopted approach takes advantage of Duhamel's superposition principles to model these vortex effects. A physics-based methodology is used to minimize the number of constants and improve generality. Both lift and pitching-moment coefficients can be obtained as outputs. The model indicial constants are extracted from computational-fluid-dynamics calculations obtained for a number of flow conditions and deployment schedules. The model is computationally inexpensive and should be adequate for use during preliminary design studies in various aerospace applications.
All Science Journal Classification (ASJC) codes
- Aerospace Engineering