Level-set simulation of the vortical flow generated by a surface-piercing body.

The flow field around a ship is extremely complex, even for the simplest case of motion through calm water with constant forward speed. In particula, many vortical strucutres are originated by the ship motion. Some of them are directly related to ship breaking waves (Landrini et al 2001). In other cases, vorticity is created at the hull boundary and shed along and downstream the ship. In this paer, we report our ongoing investigations aimed to gain fundamental understanding of the fluid dynamic processes connected with the motion of a ship. In particular, we consider a two-dimensional prototype problem consisting in a vertical flat plate, piercing the air-water interface, and moving forward with known velocity. This rather simple problem is meant to be roughly representative of the fluid phenomena occurring around a blunt ship and near a transom stern. The problem is studied numerically by a Navier-Stokes solver with a Level-Set technique to capture the air-water interface. Details of the method are presented and numerical results are discussed. Preliminary data from a companion experimental investigation, still in its infancy, are presented.