Application of an Unstructured Free Surface Flow Solver for High Speed Transom Stern Ships

Robert V. Wilson, D. Stephen Nichols, Brent Mitchell, Steve L. Karman, Jr., Daniel G. Hyams, Kidambi Sreenivas, Lafe K. Taylor, W. Roger Briley, and David L. Whitfield
The University of Tennessee at Chattanooga, Chattanooga, Tennessee, 37403

An unsteady Reynolds-averaged Navier- Stokes unstructured two-phase free surface capturing solver developed at the UT SimCenter at Chattanooga is applied to the solution of surface ship flows at higher Froude numbers, where steep and overturning waves are present. The solver utilizes artificial compressibility and a multiphase free surface capturing model to resolve the fluid motion in both the air and water regions and to manage complex free surface topologies. The one-equation Spalart-Allmaras model is used for turbulence closure. A general multielement unstructured mesh is utilized to achieve resolution requirements for the free surface interface, near-wall viscous spacing, and complex geometries. Inviscid fluxes are evaluated using a second-order accurate Roe approximate Riemann scheme and viscous fluxes are evaluated using a second-order directional derivative approach. The present paper describes the initial phase for application of the algorithm to study the hydrodynamic performance of novel hull concepts for high speed operations. Results are presented and compared with available data for the R/V Athena research vessel, a double wedge model, and a Wigley hull with incident waves.