9713110 Gangadharan The two previous research grants awarded by the National Science Foundation led to: (i) understanding of the adhesion characteristics of Enteropmorpha clathrata and their consequent effects on the hydrodynamic drag of flat plates; (ii) the design, construction and operation of a cost- effective water tunnel at Harbor Branch Oceanographic Institution, and (iii) experimental and theoretical investigation of the flow characteristics (lift, drag and pitching moment) over fouled and unfouled bydrofoils. The current research is an extension of some of this work with the intention of first, continuing the investigation of the adhesion of Enteropmorpha clathrata on hydrofoils, subsequent impact on flow field cavitation, and hydrodynamic response characteristics on hydrofoils and marine propellers; secondly to develop a detailed theoretical model of Enteromprpha clathrata fouling on hydrofoil surfaces, perform extensive experimental testing on hydrofoils in the water tunnel using the Laser Doppler Velocimeter (LDV) system, develop a model from experimental results using response surface methodology and correlate the results obtained from theory and experiments and thirdly to theoretically investigate the impact of fouling of the hull on propeller vibrations and noise. This 3-year research project will be separated into three phases: Phase I (Year 1): Involves the study of the flow characteristics around the fouled hydrofoil surface using the Laser Doppler Velocimeter (LDV) available at the water tunnel facility at Harbor Branch Oceanographic Institution. Phase II (Year 2): Involves the investigation of the impact of fouling on cavitation. The hydrofoil model will be treated as a single blade of a propeller and allowed to cavitate with fouling. The LDV system will be used to characterize the flow patters at Harbor Branch Oceanographic Institution. Phase III (Year 3): Efforts will be primarily concentrated in arriving at a relationship between the biological material properties and cavitation by inducing biological growth or to remove/minimize the biological growth on marine surfaces by inducing cavitation. ***
