Master's Dissertation
DOI
10.11606/D.3.2013.tde-14122014-124538
Document
Author
Full name
Marcos Felipe Bettini Pereira de Araujo
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2013
Supervisor
Committee
Nishimoto, Kazuo (President)
Conti, Mardel Bongiovanni de
Ferreira, Marcos Donato Auler da Silva
Title in Portuguese
Estimativa do fator de forma e da resistência ao avanço de embarcações através da dinâmica dos fluidos computacional.
Keywords in Portuguese
CFD
Double-model
Fator de forma
Froude
Linhas de correlação
Resistência ao avanço
Abstract in Portuguese
Title in English
Estimate of the form factor and the resistance of ships through the computational fluid dynamics.
Keywords in English
CFD
Correlation lines
Double-model
Form factor
Froude
Resistance
Wave pattern
Abstract in English
This work discusses the effect of scale in obtaining the form factor of ships and evaluates the estimated resistance and wave pattern generated by the relative motion between the fluid and the hull, through computational analyzes. A suitable estimate of the form factor is important for determining the resistance of the hull in full scale, enabling the sizing of the propulsion system, ie, engine and propeller. Traditionally the value of the form factor is obtained experimentally by towing tests of reduced scale models. It is observed in most laboratories that during testing the value of the form factor is assumed to be constant, regardless of Froude and Reynolds, as proposed by the ITTC. An alternative computation for determining the form factor is presented. For this purpose, the double-model method is used to simulate resistance tests of the adopted hull, in which the coefficients of viscous resistance are obtained. Meanwhile the coefficients of frictional resistance are calculated by the ITTC'57, Grigson and Schoenherr correlation lines, and by the simulation of flat plates. The relationship between the viscous and frictional coefficients show the trend of the form factor as a function of Reynolds number, considering Froude constant. The resistance values obtained in the simulations are compared to experimental data available, as well as the pattern of waves, illustrating how computational tools can be applied advantageously, that is, provides similar results to those obtained in the laboratory, but quickly and at lower cost. Briefly are also presented some mathematical descriptions that are used in the finite volume method.