Indicial Function Predictions of Two Dimensional Unsteady Viscous Flows Around Bluff Bodies Based on Discrete Vortex Simulations

This paper provides aerodynamic indicial functions obtained through a discrete vortex computational fluid dynamics method for two-dimensional geometries, including two canonical sections, rectangular and elliptical shapes, and the Great Belt Bridge cross section. This methodology enables one to determine the unsteady lift and aerodynamic moment necessary in aeroelastic analysis of flexible bodies including flutter and vortex induced vibration. The predictions were obtained using an unsteady viscous flow solver, DVMFLOW, developed by COWI. The indicial functions developed have two exponential groups which parameters have been obtained using a nonlinear least square method. The numerical investigations show significant flow separation for the presented sections and an enhanced dynamic stall region at the initiation of a transient leading to higher values in the lift coefficient response. Vortex shedding frequency was also determined and the results are compared with other studies in the literature.