INVESTAGATION OF FORM FACTOR FOR A FULL FORM SHIP: COMPARISON BETWEEN SHIP MODEL TEST AND COMPUTATIONAL FLUID DYNAMICS [豐滿船形之形狀因子探討：船模阻力試驗與計算流體力學模擬比較]
Journal
Journal of Taiwan Society of Naval Architects and Marine Engineers
Journal Volume
43
Journal Issue
1
Start Page
1
End Page
9
ISSN
10234535
Date Issued
2024
Author(s)
Abstract
This study investigates the relation between form factor and two non-dimensional parameters, namely Reynolds number and Froude number. An oil tanker with bulbous bow is selected and the resistance is evaluated by ship model test and by computer simulation method. In terms of ship model test, the resistance test was conducted under Froude number from 0.1 to 0.2 for a scale model of oil tanker, to which ITTC 1957 model-ship correlation curve and Prohaska method are applied to estimate form factor. As for computation simulation, four ship speed points are set corresponding to experiment, and commercial computational fluid dynamics (CFD) software is applied to simulate behavior of free surface and resistance component. Compared with the experiment result, the error of total resistance by CFD is low, which implies that it is acceptable to estimate form factor by Prohaska method from CFD results under circumstances of low ship speed. Therefore, a double-body model, though reducing computational complexity, is not necessary to eliminate free surface effect. The resistance component of CFD simulation result shows that form factor originates mainly from the presence of pressure resistance. In addition, viscous resistance is related to Reynolds number, while wave making resistance is related to Froude number, and both of them highly affect pressure term. In the case of very low speed, wave making pressure resistance vanishes while viscous pressure resistance remains, which proves Prohaska extrapolation method is a proper way for form factor estimation.
Subjects
CFD
Form Factor
Ship Model Test
Viscous Pressure Resistance
Publisher
Taiwan Society of Naval Architects and Marine Engineers
Type
journal article