Experimental and numerical study on trim and sinkage of a high speed catamaran vessel in shallow waterways
TL;DR: In this paper, the effect of under-keel clearance of water and demi-hull spacing in determination of a safe vessel speed was studied using RANSE based CFD solver Fluent.
Abstract: Many areas of seas, harbours and channels that were considered deep and safe for vessel navigation have been changed into dangerous shallow water regions for the new generation vessels due to their drastic increase in size and speed. Hence, the understanding of the safe speed of a vessel to prevent it from grounding when it operates in restricted waterways is gaining more importance. A catamaran vessel, being one of the new generation vessel configurations, is considered here to study the effect of its under-keel clearance of water and also its demi-hull spacing in the determination of a safe vessel speed. The numerical study using RANSE based CFD solver Fluent has been complemented by results obtained from experiments carried out in the towing tank of IIT Madras using the newly commissioned floating false bottom facility.
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TL;DR: In this paper, the authors investigated the resistance and ship-generated waves of two inland vessels in the fully-confined waterway based on numerical simulations and validated the simulation results using towing tank experiments.
20 citations
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TL;DR: In this paper, two new two-equation eddy-viscosity turbulence models are presented, which combine different elements of existing models that are considered superior to their alternatives.
Abstract: Two new two-equation eddy-viscosity turbulence models will be presented. They combine different elements of existing models that are considered superior to their alternatives. The first model, referred to as the baseline (BSL) model, utilizes the original k-ω model of Wilcox in the inner region of the boundary layer and switches to the standard k-e model in the outer region and in free shear flows. It has a performance similar to the Wilcox model, but avoids that model's strong freestream sensitivity
15,459 citations
"Experimental and numerical study on..." refers methods in this paper
...A two equation SST k−ω model [9] is solved with continuity and momentum equations to obtain the net heaving force and trimming moment acting on the ship model....
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TL;DR: In this article, the problem of disturbance to a stream of shallow water due to an immersed slender body, with special application to the steady motion of ships in shallow water, is solved, and the wave resistance and vertical forces at both sub- and supercritical speeds are used to predict sinkage and trim of ships.
Abstract: The problem solved concerns the disturbance to a stream of shallow water due to an immersed slender body, with special application to the steady motion of ships in shallow water. Formulae valid to first order in slenderness are given for the wave resistance and vertical forces at both sub- and supercritical speeds. The vertical forces are used to predict sinkage and trim of ships and satisfactory comparisons with model experiments are made.
183 citations
TL;DR: In this article, a review is made of linear slender body methods for predicting the squat of a ship in shallow open water, dredged channels or canals, summarized into a general formula based on Fourier transforms, and the method is extended to cater to stepped canals.
61 citations
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...Gourlay [7] presents expressions for squat of ships operating in shallow water and channels, with different types of stepping, using slender body theory....
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TL;DR: In this article, it was shown that for a ship towed from the bank, or by any external force, there are three distinct speed ranges: subcritical, critical and supercritical.
Abstract: In this paper some simple theoretical considerations concerning the movement of ships in restricted waterways are discussed, and it is shown that for a ship towed from the bank, or by any external force, there are three distinct speed ranges: subcritical, critical and supercritical. In the subcritical and supercritical ranges, Bernoulli's equation and the continuity equation are satisfied everywhere by a state of steady motion relative to the ship, but in the critical range these laws require that a quantity of fluid is piled up continuously ahead of the ship in the form of a bore. Experimental confirmation is given by means of photographs of model tests.
48 citations
"Experimental and numerical study on..." refers background in this paper
...Constantine [3] considered the case of a ship traveling in a narrow and shallow channel....
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TL;DR: In this paper, a high speed ferry, with LCB and LCF quite aft of midship, is considered for squat study for a vessel speed of above 6.0 knots and for a waterway width greater than the vessel length, there appears an increase in sinkage at the stern accompanied by a large value of bow emergence.
26 citations