Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The hydrodynamic characteristics of three typical ship-like hull sections, in
different motions, are numerically investigated using FLUENT, 2009. These
simple shapes, namely a v-bottom (triangle) hull, a at-bottom (square) hull
and a round-bottom (semi-circle) hull, are investigated in uncoupled heave,
sway and roll. The problem is described in two dimensions. A combination of
numerical methods and models, found in literature, are used to conduct this
investigation. Hull characterisation is achieved through the use of hull mass
and damping coe cients. These numerically determined coe cients are compared
to experimental work conducted by Vugts (1968). A good correlation
between the numerical and experimental results exists for the heave and sway
cases. By normalising the coe cients, different hulls are comparable to one
another. The numerical models used are validated and veri ed. Roll motion
remains largely unsolved for very large angles of roll (in excess of 11°). Different
uid ow phenomena occurring around the hull sections have varying
degrees of in uence on the motions of a hull. It is found that not one of the
turbulence models investigated can be employed to globally solve each type
of hull-motion case. Also, forced oscillations in computational simulations require
considerably more computational time than free-decay oscillating hull
simulations. / AFRIKAANSE OPSOMMING: Die hidrodinamiese karakteristieke van verskillende skeepsrompvorms, in verskeie
bewegingswieë, is numeries ondersoek met behulp van FLUENT, 2009.
Drie eenvoudige vorms ('n v-bodem (driehoek), plat-bodem (reghoek) en rondebodem
(semi-sirkel) romp) is onderskeidelik ondersoek in opwieg, dwarswieg en
rol. Die probleem is twee-dimensioneel. Daar is gebruik gemaak van 'n kombinasie
van numeriese metodes en modelle, uit die literatuur, om die ondersoek
uit te voer. Die rompe is gekarakteriseer met behulp van massa- en dempingskoëffi siënte. Hierdie numeries bepaalde koë ffisiënte is vergelyk met die
eksperimentele werk van Vugts (1968). Daar bestaan 'n goeie korrelasie tussen
die numeriese en eksperimentele resultate vir die opwieg en dwarswieg gevalle.
Die koë ffisiënte is genormaliseer om die verskeie rompvorms te vergelyk. Die
numeriese modelle is geverifi eer en valideer. Rolbewegings is onopgelos vir
groot rolhoeke (groter as 11°). Die mate waartoe die romp se beweging beïnvloed
word deur die verskillende vloei verskynsels wat om die rompe ontstaan,
verskil. Daar is bevind dat geen van die turbulensie modelle gebruik kan word
om alle skeepsbeweging-gevalle op te los nie. Gedwonge-ossilasie numeriese
simulasies benodig meer berekeningstyd as vrye-verval ossilasie gevalle.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/18033 |
| Date | 12 1900 |
| Creators | Henning, H. L. |
| Contributors | Thiart, G. D., Harms, T. M., Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 132 p. : ill. |
| Rights | Stellenbosch University |
Page generated in 0.0021 seconds