Globalization is reaching the furthest corners of the world and with globalizations comes a rising demand on transportation. In shipping; a significant cost both to the ship owners and the environment are the fossil fuels used for propulsion, even a small reduction in the wave resistance can bring considerable reductions both in operating costs and emissions for such ships. When designing a ship it is important to be able to make fast and accurate predictions of its resistance so that more efficient hull forms can be selected early in the design process. A panel method based on potential flow is a fast scheme to determine the wave resistance and is therefore suitable to be used early on in the design process. Here it is shown that potential flow can be improved by including Rayleigh damping, added viscous effects that will make the flow dissipative. Dissipative Green functions are employed in the proposed technique with the resulting velocity potential determined from a combination of a source distribution and a modified distribution of vortices on submerged 2D bodies. NACA hydrofoils, Joukowski hydrofoils and cylinders are used to test the model. The pressure distribution is more in line with experimental results than previous numerical methods without added viscosity for the NACA hydrofoils. The surface profile has very good comparison with existing numerical results for a NACA hydrofoil in subcritical speeds. However the results are very poor for the Joukowski hydrofoil. There is therefore reason to develop this method further in both 2D and 3D.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:kth-74700 |
| Date | January 2011 |
| Creators | Fürth, Mirjam |
| Publisher | KTH, Marina system |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | Trita-AVE, 1651-7660 ; 2011:68 |
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