Study on the Powering Prediction and Interference Effects of Catamaran
Date Issued
2010
Date
2010
Author(s)
Lin, Mung-Whua
Abstract
The purpose of this research is to study the powering prediction and resistance interference effects of catamaran from ship model test results.
First, the viscous interference and wave-making interference of catamaran with the parameters of Froude number and the separation of the demihull were studied based on experimental results by Insel and Molland[12].
At first, the wave-piercing catamaran model was used to study the interference effects by ship model test. The test results show that there exist interference effects between the demihull of catamaran as shown in the tested results of Insel and Molland[12]. Following, the Wigley hull form, which has parabola geometry, was used to study the detailed interference effects of catamaran. The resistance performance with different separation distance between demihull was measured and the viscous interference and wave-making interference were also calculated from the test results. The full scale resistance of the catamaran was predicted by Froude’s method and form factor method. It is found that there is no interference effect if the non-dimensional separation distance S/L is greater than 0.4 for the wave-piercing catamaran and 0.7 for the Wigly hull form. The interference effect is due to the sinkage and running trim changed caused by the buoyancy changed from the interaction of two bow waves meeting in the channel between the demihulls. The negative interference of resistance is also due the changed of the sinkage and running trim.
Finally, through the comparison between the calculated results and test results, it is found that the trend of the calculated wave-making resistance is the same as that of tested. But, the value of calculated wave-making resistance is a little bit smaller than the tested wave-making resistance. The values of form factor, viscous interference and wave-making interference of Wigly were verified with that of Insel and Molland[12]. It is found that if the resistance of low speed could be measured accurately, than the form factor could be determined accurately and the full scale resistance could be predicted accurately.
Subjects
interference effect
powering prediction
viscous interference
wave-making interference
wave-piercing catamaran
Wigley hull
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-98-R97525006-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):5b319b321b636edf219b64d63addb43f