Resistance and Wash Wave Measurements On A Series of High Speed Displacement Monohull and Catamaran Forms In Shallow Water

Molland, A.F.; Wilson, P.A.; Taunton, D.J.; Chandraprabha, S.; Ghani, P.A.

doi:10.3940/rina.ijme.2004.a2.3604

Cited by 24 publications

(23 citation statements)

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“…The investigation of the effects of the separation distance on the resistance components was also carried out by Millward (1992); and Molland et al (2004), by means of both experimental tests and theoretical approaches. A considerable amount of research has been carried out to determine the resistance interference effects of demihulls of catamarans in proximity of one hull adjacent to the other, including experimental and theoretical work from Sahoo et al (2007) and Muller-Graf et al (2002).…”

Section: Introductionmentioning

confidence: 99%

An Investigation into the Resistance Components of Converting a Traditional Monohull Fishing Vessel into Catamaran Form

Samuel¹,

Iqbal²,

Utama³

2015

IJTech

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Resistance or drag is one of the most important factors in ship design, in particular in connection with the development of more efficient and environmentally friendly vessels. The shape of the hull under water will affect the fluid flow characteristics around the ship, hence causing the resistance to increase or decrease. If the resistance increases, the size of main engine and subsequently, the fuel consumption increases accordingly and this is not often anticipated by ship designers and operators. The use of a catamaran for passenger carriers is well known and its application for fishing vessels has received serious attention in the last few years, due to its advantages to produce wider deck area and smaller size of engine at the same displacement as the monohulls. The conversion of monohull fishing vessels in Cilacap the waters into a catamaran hull is an interesting topic in association with the development of better fishing vessels in this region. The resistance investigation of the conversion vessel was carried out by Computational Fluid Dynamics (CFD) approach and this is combined with classical slender body theory. In terms of mathematical calculation, the results between CFD and the combination of empirical formulas and slender body theory shows such a good agreement and the difference between the two is less than 5%. In terms of naval architecture, the results showed that the modification of a monohull vessel into a catamaran can increase the payload capacity up to two times. Conversely, this causes the resistance to increase about almost four times and this is certainly unpopular for the fishermen.

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Section: Introductionmentioning

confidence: 99%

An Investigation into the Resistance Components of Converting a Traditional Monohull Fishing Vessel into Catamaran Form

Samuel¹,

Iqbal²,

Utama³

2015

IJTech

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“…Cheng et al [3] developed a mathematical theory for the practical design of an asymmetric demi-hull, the S-catamaran, whose hull sections were theoretically determined to eliminate or at least substantially reduce wave resistance at supercritical design speeds in shallow water. Further experimental and theoretical investigation of the interference phenomena was also carried out in Millward [4] and Molland et al [5]. SoutoIgleasias et al [6] investigated experimentally the influence of the distance between catamaran hulls on wave resistance.…”

Section: Introductionmentioning

confidence: 98%

Numerical analysis of the interference effects on resistance, sinkage and trim of a fast catamaran

Castiglione

Kandasamy

et al. 2014

J Mar Sci Technol

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The purpose of the present paper is the numerical investigation of the interference phenomena between the waves generated by the individual hulls of a catamaran. The study focuses on the effects of both Froude number and demi-hull separation distance on resistance and on sinkage and trim. The numerical simulations are carried out by the URANS solver CFDShip-Iowa V.4 and, to assess the capability for prediction of resistance, sinkage and trim of the URANS code for twin-hull configuration vessels, a verification and validation study is performed for global as well as for local variables. A very good agreement between the numerical results and the experimental data is obtained, and the validation study demonstrates the high level of accuracy of the current predictions, which are used to have a better insight into the interference phenomena. In accordance with the experiments, within Fr = 0.45-0.65, the catamaran has a significantly higher resistance coefficient compared to the mono-hull; furthermore, the C T value increases with decreasing the separation distance between the twin hulls. On the contrary, at Fr lower than 0.45 and at Fr higher than 0.65, the effects of hull spacing on resistance as well as on sinkage and trim can be neglected. The flow field characteristics, wave pattern, wave cuts and pressure distributions are analyzed through the CFD analysis. Finally, the effects of the Reynolds number on resistance are also investigated and results show a small decrease in interference with increasing the Reynolds number.

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“…hulls. Molland et al (2004) provided extensive resistance and wave measurements of a series of high-speed displacement monohull and catamaran hull forms, including sinkage and trim. Tarafder and Suzuki (2006) computed the free surface flow around ships in shallow water using a potential flow-based panel method, allowing for hull forms other than the simplified one used by Kirsch (1966).…”

Section: Introductionmentioning

confidence: 99%

Planing in Shallow Water at Critical Speed

Morabito¹

2013

Journal of Ship Research

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This article summarizes experiments to determine the effect of shallow water on flatbottomed prismatic hulls towed fixed in heave and trim over a wide range of speed regimes. The experimental design allowed for the separate measurement of pressure forces normal to the bottom and viscous forces tangential to the bottom. The experiments showed that below a depth Froude number of unity (subcritical speeds), shallow water resulted in a reduction in pressure forces on the bottom of the hull. Around a depth Froude number of unity (critical speed), a solitary wave formed at the model, increasing the wetted length and also increasing the bottom pressure forces, which became unsteady. Above a depth Froude number of unity (supercritical speeds), the pressure forces on the bottom of the hull were greater in shallow water than in deep water. Observations of the inception of transom ventilation showed that full ventilation occurred at lower Froude numbers in shallow water and that trim has a strong effect on transom ventilation at all water depths. To assist in explaining these effects, each of the forces acting on a flat-bottomed hull are discussed and it is shown how they vary with speed and water depth. The observed trends from these fixed model tests are in qualitative agreement with experiments with free to trim and heave models as well as two-dimensional theories of planing in shallow water.Early work on shallow water effects such as Schlichting (1934), Landweber (1939, and Lackenby (1963) focused on estimating the speed loss of seagoing displacement ships during sea trials in shallow or restricted waters or estimating towing tank blockage corrections. It has been found that as the depth Froude number approaches unity (critical speed), there is an increase in resistance, which often results in speed loss for ships.Supercritical behavior of displacement and semidisplacement hulls has been studied more recently. Kirsch (1966) computed the theoretical wave resistance for a simplified ship form in shallow and restricted channels using Sretenskii's (1937) method. Calculations were at subcritical and supercritical speeds, showing that resistance decreased in shallow water at supercritical speeds. Millward (1983) and Millward and Bevan (1986) extended Kirsch's calculations and found that the method correlated well with resistance measurements from towing tests of semidisplacement Manuscript received as SNAME headquarters

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Resistance and Wash Wave Measurements On A Series of High Speed Displacement Monohull and Catamaran Forms In Shallow Water

Cited by 24 publications

References 0 publications

An Investigation into the Resistance Components of Converting a Traditional Monohull Fishing Vessel into Catamaran Form

An Investigation into the Resistance Components of Converting a Traditional Monohull Fishing Vessel into Catamaran Form

Numerical analysis of the interference effects on resistance, sinkage and trim of a fast catamaran

Planing in Shallow Water at Critical Speed

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