Vortex-structure Interactions

Maneuvers of solid bodies in fluid often create vortices. These vortices not only dominate the flow but also contribute to the force exerted on solid surface/structures.

Unsteady aerodynamics

The flying mechanism of insects and small birds like hummingbirds is very different from conventional fixed-wing aircrafts. They rely on unsteady motions of their wings to create vortices and generate lift. The dynamics is unsteady, and vortices are shedding from the leading and trailing edges. Simulations using CFD have been very expensive for this problem. Vortex methods could provide another appropriate approach.

Leading-edge vortex (LEV)

Man-made vehicles in water or air rely on control surfaces to adjust their attitude and motion for them to maneuver in air/water. When these control surfaces are in action, they usually create a high angle of attack with the oncoming stream and a lateral force is generated. The flow separates from the leading edge of the surface and a leading-edge vortex will emerge. When a CFD scheme, such as LES or RANS, is used to simulate the flow field, the computational grids and operations require large computer efforts and costs. Vortex sheets or a series of point vortices can be used to approximate the flow field, and the computational cost can be significantly reduced. The low CPU time can provide a possible real-time estimate in engineering applications.

Vortex shedding