Recently the leading-edge tubercles on the pectoral fins of humpback whales have attracted the attention of researchers who wish to exploit this feature in the design of turbine blades to improve the blade performance. The main objective of this paper is therefore to make a further investigation into this biomimetic design inspiration through a fundamental research study involving a hydrofoil section, which represents a straightened tidal turbine blade, with and without the leading-edge tubercles, using computational and experimental methods. Firstly a computational study was conducted to optimise the design of the leading-edge tubercles by using commercial CFD code, ANSYS-CFX. Based on this study the optimum tubercle configuration for a tidal turbine blade with S814 foil cross-section was obtained and investigated further. A 3D hydrofoil model, which represented a "straightened" tidal turbine blade, was manufactured and tested in the Emerson Cavitation Tunnel of Newcastle University to investigate the effect of various tubercle options on the lift and drag characteristics of the hydrofoil. The experiments involved taking force measurements using a 3-component balance device and flow visualisation using a Particle Image Velocimetry (PIV) system. These tests revealed that the leading-edge tubercles may have significant benefits on the hydrodynamic performance of the hydrofoil in terms of an improved lift-to-drag ratio performance as well as reducing the tip vortex which is main cause of the undesirable end-effect of 3D foils. The study explores further potential benefits of the application of leading-edge tubercles on tidal turbine blades

The rising environmental awareness of various adverse emissions by commercial shipping has recently targeted Underwater Radiated Noise (URN) due to its potential impact on marine mammals. Amongst the various sources on-board a commercial ship, cavitation is the dominating one following its inception. In order to ensure acceptable noise levels for sustainable shipping, accurate prediction of the noise signature is vital. Within this framework, a widely utilized method for full-scale noise prediction is to conduct model tests in cavitation tunnels and to extrapolate to full-scale. The aim of this paper is to provide invaluable URN data of a full-scale vessel and its prediction using cavitation tests from a medium-sized tunnel to evaluate the prediction methodology. Extrapolated URN data based on the tunnel tests was compared with the data obtained from the full-scale trials with The Princess Royal in order to assess the prediction methodology. The comparisons indicate that, whilst the ideal experimental approach is to conduct such involving tests with a full-hull model in large cavitation tunnels, the medium size facilities using dummy-hull models with wake screens, can still provide a very useful means for the URN investigations with a rapid turn around and an economical way of conducting such tests

The effect of shaft inclination can induce important unsteady hydrodynamic phenomenon usually associated with small and high-speed craft. This paper presents systematic cavitation tunnel tests with a 214mm diameter model propeller of a catamaran research vessel. The propeller is subjected to uniform and inclined flow conditions, to investigate its efficiency, cavitation and underwater radiated noise characteristics. The experiments were conducted in the Emerson Cavitation Tunnel of Newcastle University based on the starboard 5-bladed right-hand propeller of the University's research vessel, The Princess Royal. In the paper the details of the tests and significant findings for the effect of the shaft inclination on the propeller efficiency, cavitation and underwater radiated noise characteristics are presented. A better understanding is sought in relation to the noise signatures of different types of cavitation. The systematic tests presented in the paper also have a long-term objective, being the first of an organized round robin test campaign that is being currently undertaken by the members of the Underwater Noise Community of Practice (CoP) of Hydro-Testing Forum (HTF). This long-term objective is to repeat similar tests in the different facilities of all CoP members to reveal the relative merits of their testing facilities for underwater noise investigations.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence Newcastle University ePrints -eprint.ncl.ac.uk Li C, Atlar M, Haroutunian M, Anderson C, Turkmen S. An experimental investigation into the effect of Cu2O particle size on antifouling roughness and hydrodynamic characteristics by using a turbulent flow channel. Ocean Engineering 2018

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