Some Modelling Issues on Trailing Edge Vortex Shedding

A numerical study has been carried out to investigate modelling issues on trailing edge vortex shedding. The vortex shedding from a circular cylinder and a VKI turbine blade is calculated using a 2-D unsteady multi-block Navier-Stokes solver. The unsteady stresses are calculated from the unsteady solutions. The distributions of the unsteady stresses are analysed and compared for the cylinder case and the cascade case, respectively. The time-averaged equations are then solved and the effectiveness of the “unsteady stresses” in suppressing trailing edge vortex shedding is checked. Finally, the time-independent solution produced by solving the time-averaged equations is compared with the time-averaged solution obtained by integrating the unsteady solutions. The numerical results have demonstrated that a time-independent vortex shedding solution can be achieved by solving the Navier-Stokes equations with the unsteady stresses and the time-averaged effects of the vortex shedding can be included.