Flutter Derivative Identification using Turbulence Modelling

The 2D discrete vorticity method [1] and a vorticity-stream function formulation [2] were employed previously for aeroelastic study of prismatic structures. The two-equation k-? model was applied to simulate flows around stationary rectangular sections with different aspect ratios (B/D=Breadth/Depth) and satisfactory results have were reported [3]. The current work is to test applicability of two-equation RANS models in aeroelastic study of prismatic structures with streamlined or bluff sections. For this the k-ω model and the shear stress transportation (SST) model, a derivative of k- ω, both allowing low Reynolds number treatment of boundary layers, have been used on the NACA0012 and the B/D=4 rectangular sections pitching or translating in a sinusoidal way. The resultant unsteady aerodynamic pressure and friction on the model are integrated o give the transient drags, lifts and moments. Combined with the motion function specified for the model, the flutter derivatives (FD) of the sections are identified. The simulated FDs are compared with the Theodorsen theoretical values for the NACA-0012 section; with the Huston’s experimental results for the rectangular section. Good agreement is observed indicating the RANS turbulence models can be potentially applied to aeroelastic study of prismatic structures with streamlined or bluff cross sections.