Free Surface Effects on Horizontal Hydrofoils

Abstract

The current report is the result of two students master thesis project at Chalmers University of Technology in the master programme Naval Architecture and Ocean Engineering. This project aims to investigate the influence of a free water surface on hydrofoils using the Computational Fluid Dynamics (CFD) software StarCCM+. This is investigated by running simulations for different depths of submergence, angles of attack and Froude numbers. The results of the simulations are studied by producing plots of the lift forces, drag forces, wave patterns and streamlines around the wing. The different phenomena that can be observed when the Froude number (Fn) and the depth of submergence are varied are explained using the produced results. The report includes theory about the fluid dynamics used in this project, theory about the methods that are used in the project as well as basic theory about hydrofoil hydrodynamics. This is followed by the methodology and recommendations from the StarCCM+ manual (“STARCCM+ ® Documentation Version 12.04”, 2017) to set up the simulations used in the project. Lastly the results from the conducted simulations are presented together with conclusions and explanations of the different phenomena that are observed, that also are linked to boats where hydrofoils have been applied.