The development of time-dependent biofouling model for ships

Student thesis: Doctoral Thesis

Abstract

Despite a large amount of research, the effect of barnacle fouling on the frictional resistance has a lack of systematical experimental investigation focussing on parameters such as size, coverage area and settlement pattern. Limited roughness functions data about barnacle fouling is available in the literature. Moreover, although a large number of the study has been carried out on the effect of roughness on the frictional resistance, only the limited lab-based results were extrapolated to the full-scale ship results (Schultz et al.,2011).;In addition, antifouling precautions cost 5% of the total fuel-oil cost of world fleet for a year, and to the best of the author's knowledge, there is no scientifically settled approach for selecting the best antifouling coating for the ship in question. This situation forced vessel owners/responsible person have their particular strategy to deal with marine fouling based on personal experience or negotiating with the sales personnel of the paint company.;Based on the background given above, an extensive and systematic experimental study was carried out for investigating the effect of barnacle fouling on ship resistance and powering. One of the most common barnacle geometry was produced on bundles through a 3D technology and attached on the flat plates for towing tank experiments at Kelvin Hydrodynamics Laboratory in the University of Strathclyde. Eighteen different configurations varying in terms of size, coverage area and settlement pattern were tested. Drag characterisations, determination of roughness functions and full-scale extrapolations were performed.;A simplified time-dependent biofouling prediction model for ships was developed in order to be used as a decision support tool, regarding the effect of biofouling on ship resistance due to the performance of the antifouling coating. First, a growth prediction model was developed based on the antifouling field test data (fouling ratings in time) and then time parameter of this model was assigned to the idle times of ships coming from ship operational data. The fouling ratings were predicted in time according to this data, and then these fouling ratings were converted into the sand roughness height in accordance with the roughness data provided in the literature and this PhD thesis. Predicted equivalent sand roughness heights were then employed in the Granville similarity law scaling process to predict the increase in the ship frictional resistance and powering. Finally, the results were compared with real-world operation data and ship performance report provided by a ship performance analysis company. The results of the comparison showed that there is a good agreement between the predictions and real-world operation data as well as the company report.
Date of Award13 Mar 2020
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsUniversity of Strathclyde
SupervisorOsman Turan (Supervisor) & Yigit Kemal Demirel (Supervisor)

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