The hullform of a ship is decisive for its energy consumption and efficiency in that a large part of the overall resistance is determined by form effects and the aft body shape influences the propulsive losses. The shape related aspects are traditionally the domain of a ship model basin and HSVA is no exception. While in the past numerous physical ship models have been created and tested in a towing tank to find the optimal solution, this role has been taken over by CFD, numerical methods which allow analysing the performance of a ship hull before the first model is built. HSVA employs different methods to compute hull resistance at different stages of a design:
- Potential flow methods (ν-SHALLO) are used for rapid initial design space exploration.
- Viscous methods (FreSCo+) are used for accurate and detailed design investigations.
HSVA experts apply CFD methods over a period of more than 20 years already, constant advancement of the CFD codes included. Their work resulted in substantial improvements of ship hullforms for vessels as diverse as tankers, bulk carriers, container ships or RoRo and Passenger ships. On average an improvement of (5) % can be obtained, In individual cases enhancements up to (15-20) % have been found. Modern challenges include form optimisation for a much larger design space which includes different operating conditions, e.g. speed or draft / trim variations resulting from operational requirements. These can be covered using CFD codes more quickly and efficiently than in model testing.
Traditional search-based optimisation strategies have been established since long. Together with our development partner TUHH advanced optimisation concepts using adjoint solvers are presently explored in projects and tested on a number of hullforms.