Adjoint-based Shape Optimization of a Ship Hull Using Various Propeller Resolution Methods: Methodological Aspects
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The environmental footprint as well as the direct operating cost of a ship are governed by the fuel consumption, which in turn depends on the hydrodynamic efficiency of the hull. The latter is partially governed by the interaction between the hull and the propeller [1]. Therefore, efficient simulations-based optimization methods able to concurrently resolve the fluid dynamics around the ship hull and its’ propulsion system are highly appreciated. High-fidelity methods, in which the transient rotational motion is resolved by a corre- sponding rotation of the propeller grid, are afflicted by substantial computational costs due to the unsteady nature of the application. Computationally efficient alternatives to the transient primal rotational motion and their adjoint counterpart are, thus, important and can be the first step towards an efficient unsteady hull-shape optimization. To this end, we present different routes to an adjoint-based shape optimization method that distinguish in the treatment of the rotating propeller. Strategies discussed refer to simple body-force approaches, moving reference frame (MRF) [2], fully resolved grid rotation and their hybrids. REFERENCES [1] J.E. Kerwin and J.B. Handler. Propulsion. SNAME, 2010. [2] J. Aubin, D. F. Fletcher, and C. Xuereb. Modeling turbulent flow in stirred tanks with CFD: The influence of the modeling approach, turbulence model and numerical scheme. Experimental Thermal and Fluid Science, 28:431–445, 2004.
