SBIR-STTR Award

Development of the capability to predict flow fields around naval ships,submarines in particular, both accurately and efficiently is crucial to the Navy in the design of naval ships. State-of-the-art Reynolds-averaged Navier-Stokes solvers are capable of predicting the general flow field a=out an appended submarine , but there are two major shortcomings: the long computing time required and the lack of resolution of the vortical flows generated in junctures and appendage tips of the sulxnarine. The multilevel adaptive method can overcome these two shortcomings by improving the rate of convergence of the solver by an order of magnitude,therefore significantly reducing computing time, and by placing denser grid distributions strategically in regions where the vortical flow dominates, enabling accurate resolution of the vortical flow. The implementation of the multilevel adaptive methods with an existing 3-D Reynolds-averaged Navier-Stokes solver, such that the vortical flows generated by appended submarines can be both accurately and efficiently predicted, is the main goal of the proposed Phase I project. The improvement and the development of more accurate and efficient numerical schemes is the goal of the Phase II project.

Development of the capability to predict flow field around naval ships, submarines in particular, both accurately and efficiently is crucial to the Navy for effective design. State-of-the-art Reynolds-average Navier-Stokes solvers are capable of predicting the general flow field about an appended submarine, but there are two major shortcomings: the long computing time required and the lack of resolution of flows at juncture and appendage tips of the submarine. The propose Phase II can overcome these two shortcomings by improving the rate of the convergence of the solver by one or two orders of magnitude and by providing dynamic adaptive grid generation and solution to get accurate resolution for the vertical flow. The Phase II approach also includes fully implicit time-marching and high-order differencing on a stretched and staffered grid, a new plane-box relaxation, a semi-coarsening multigrid and local refinement code, which will be issued at the end of Phase II, will provide the means to assess various complex flows with general geometries. This will significantly shorten the design iteration process for new ships.