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Optimum hull spacing of a family of multihulls
Abstract and Figures
Multihull congurations are optimised for minimum wave-making using thin-ship theory. Only the number of hulls, and their placement and beams are varied, the total displacement of the vessel and the individual hull length and shape being xed. In particular, optimum congurations are determined for two, three and four-hulled vessels, with and without longitudinal stagger. An example of use of this theory is given, for a family of multihulls relevant to a high-speed ferry design. Competing designs within this family are assessed over a large speed range, with respect to generated wave amplitude, wave resistance, and total drag.
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... They took note that optimum hulls could change significantly according to speed and separation. Mostly their research (Tuck & Lazauskas 1998, 2001 in numerical resistance of Multihull and optimisation studies of the side hull configuration. Also, they founded an impressive reduction in wave resistance, hull spacing and forward speeds. ...
... The complex amplitude function A() related to the wave elevation of a ship expressed as the free wave spectrum or Kochin function (Tuck & Lazauskas, 1998); the wave number k() = k0 sec 2 ; k0 = g/ V 2 . ...
... According to Tuck and Lazauskas (1998) and Day et al. (2003), the wave resistance of Multihull is calculated by separating the waves of each hull into a single hull. Thence, the waves generated by amplitude functions are also considered single. ...
This study was conducted to optimise warp-chine pentamaran configurations in wave cancellations to a significant total resistance reduction for a wide range of speed. The optimisation of a pentamaran with a warp-chine hull form was performed by a computer program Godzilla based on Michell's theory and validated by the towing test. The distance parameters of the outrigger were evaluated to select the lowest resistance generated. Computational analysis depended on the Michell-based tool compared to a commercial Computational Fluid Dynamics (CFD). The comparison of the measurement test of the total resistance and Michell's calculation results of all configurations showed a suitable trend, especially at Fn ≥ 0.4. However, it was not satisfactory for CFD trend. The illustrated of far-field wave pattern by the Michell-based instrument also consistent with the wave spectrum that captured in the test. The results of the analysis and observations revealed that the test measurement for all configuration models in the same estimated error (uncertainty) range of the total resistance. This optimisation has confirmed the stagger at the range of 0.36L-0.42L where the front outriggers and the after outriggers not in line of clearance as in arrow formation significant in wave cancellation and resistance reduction.
... Ackers et al., [8] showed that using symmetrical chine hull had a significant effect on the interference resistance caused by the interaction between the waves and the bow, the main hull and the side hulls. On the contrary, E. O. Tuck and L. Lazauskas [9] showed that symmetrical chine hull gives the lowest resistance and the highest propulsive efficiency. Moraes [10] used symmetrical chine hull at catamaran ships and obtained similar results and compared them with Wigley. ...
... Some of the researchers, i.e. Tuck and Lazauskas [9], Moraes [10], Hanhirova [18], Peng [19], Day et al., [20] and Yeung et al., [21], agreed that wave resistance of a high-speed monohull and multihull as given by Michell's integral was quite good with computed values in a towing test. The characteristic of the hull shape allows interference factors between the divergent and the transverse systems to generate wave resistance. ...
... Tuck and Lazauskas [9] provided an assumption that transverse waves can eliminate with determined main hull on a half of total displacement and each side hulls on a quarter ( = 1/4), which staggered longitudinally by an odd multiple of a half wavelength and that stagger s = /k0 takes the minimum value to cancel transverse waves. The total resistance minimisation of multihull determined by individual outrigger displacement (), stagger (s), clearance (w) on minimising complex expression Eq. (13) with G () is ...
The interaction between hulls, their position and shape and the length of the side hulls of a multihull affect the amount of wave resistance. This paper presents computation based on Michell's theory on the various configurations of pentamaran and correlates with towing test data that involves interference flow around the component hulls. The pentamaran hull form was featuring a warped chine for the main hull recommended by Savitsky and V model for outriggers. Analysis of both transversal and divergent waves was performed to assess the magnitude of wave resistance that occurs due to the placement of the side hull to the main hull. Furthermore, investigations on far-field wave pattern, wave interference, wave resistance as well as total resistance have been conducted. Changing of the side hull on clearance strongly affects the resistance characteristics than stagger. Configuring the pentamaran so that the main hull is placed at the centreline of each of the front-side hull approximately 15°-18°could be an effective manner to reduce resistance. In general, all of the resistance components results showed that Michell's theory agree with the test, particularly at Fn greater than 0.5, in which possible viscous factors were still influential at low speed where the theoretical prediction could not be potentially valuable.
... This work represents the method of resistance calculating the hull form based on thin ship theory approach. Several studies from [1] - [5] have widely discussed this theory in several hull shapes, both monohull and Multihull. In general, their answers indicated that the computation of wave resistance based on the thin ship theory from Michell is quite good both in monohull and Multihull with the test data on the towing tank. ...
... Wave resistance is according to thin ship theory [1] based on the ratio of length to width of the shape of the ship as thin. The centre of the formation of a wave profile as z = (x, y) moves at various angles propagation relative to the negative x-axis to the motion of the ship. ...
... Peng et al. [3] stated that the variation of side-hull longitudinal position, as well as transversal, affects mostly the multihull performance. From the investigation of Tuck and Lazauskas [4], side-hull position influenced interference resistance of any multihull configuration. ...
... After that, they fell until the end of the examined Froude number. The result demonstrated a steady decrease of resistance at high Froude number range that showed a convergence result with Tuck and Lazauskas [4] and Yanuar [15]. Furthermore, not a single configuration showed the best resistance characteristic across the entire speed range at a similar value of hull separation. ...
The needs to reduce energy consumption have to be applied to all sector, and one of them is transportation. Shipping is the most significant component of it, and therefore optimising a ship performance and reducing its resistance is a subject for many researchers. One of many ways to reduce drag is by utilising an alternative design such as multihull vessel, especially pentamaran, a vessel with five hulls. Destructive interference between their system of waves produced by their hulls is beneficial to reduce power consumption. An experimental test of X-pentamaran model in calm water condition had been conducted to investigate the interference resistance. Wigley hull-form of the model with four asymmetric-hull configurations and three variations of hull separation was investigated. The ship model was towed in a fixed towing condition and calm water condition with Froude number ranging from 0.2 to 0.7. The results showed that the hull separation made a slight alteration of the total resistant coefficient (in magnitude) on the same configuration. Even though not a single configuration outperformed the others in the entire range of Froude number, two configurations with S/L=0.11 showed the highest drag reduction performance as the optimum model based on their Froude number range: configuration A3 from Froude number ranging from the initial to 0.6 and configuration C3 for the rest of the Froude number range.
... The Rankine source method is considered fast, efficient, and highly precise in potential flow theory, e.g., Rankine source method with the optimization algorithm Nonlinear Programming Method (NLP) in monohull (Zhang and Zhang, 2015) and multihull optimization (Von Graefe et al., 2013;Von Graefe et al., 2015). The Michell integral method or thin ship theory is considered a more straightforward and faster CFD method (Tuck and Lazauskas, 1998). Several studies (Yanuar and Sulistyawati, 2018;Sulistyawati et al., 2020a;Sulistyawati et al., 2020b;Sulistyawati et al., 2020c) used Michell theory to investigate the hydrodynamic characteristics of pentamarans and compared them with experiments. ...
In general, evaluation of ship
hydrodynamic efficiency could be produced by an energy-efficient and
concentrated cost function. An optimization method with the representation of
hull geometry is one of the preliminary design steps that are most appropriate
for evaluating hydrodynamic performance. This work presents a comparison of two
numerical methods for optimizing the shape of the hull concerning the minimization
of total ship resistance in calm water conditions. The optimization method uses
a theoretical approach based on Michell's integral and Rankine source methods.
The discussion of the two methods emphasizes the comparison of wave resistance,
total resistance, wave profiles, and wave contour. The optimized hull form
comparison of total resistance between Michell's integral and Rankine source
methods decreased by 3.79% and 4.0%, respectively. Comparing wave resistance
with decreases by 5.52% based on Michell's integral method and 13.33% by the
Rankine source method, the wave profiles generated by these two methods present
a fair amount of compatibility. The wave contour illustrates a reasonably
straightforward agreement on the optimal hull but are dissimilar on the initial
hull.
... In the literature, numerous towing tests had been conducted on pentamaran (five hulls) configurations [3][4][5][6] while numerical studies had investigated optimum distance and expected wave resistance as well as the interference of Multihull configurations [7,8]. This research, therefore, aimed at investigating the hydrodynamic characteristics of pentamaran hulls in Wigley and warp-chine forms by using " Michlet 9.32" tool, which was based on Michell's thin-ship theory, and validating the results with towing tests. ...
The wave flow pattern builds up along the hull and expansion flow behind the hull is absorbing the energy from the ship as a resistance. The ship’s resistance and the behaviour of its components are significant in estimating the propulsion of the ship, which positively influences fuel consumption. The aimed of this work was investigating the influence of two hull forms and its outriggers arrangement in pentamaran systems. The investigating was in wave resistance, interference, and far-field wave spectrum. This study focused on warp-chine and Wigley hull shapes by comparing a computation which was based on Michell’s thin ship theory and various tests in clearance and stagger of side hulls. The results of this study founded the resistance coefficients based on Michell’s approach agreed with towing test results at Fn > 0.5. Besides, wave resistance for warp-chine configurations was established to be much better than Wigley except at Fn < 0.5. High coefficient reduction for warp-chine hulls was generated with a setting where the main hull to side hull on a formation as an arrow trimaran near to Kelvin angle. As for Wigley, the high reduction was produced by a configuration where the front-side hull and the stern-side hull were in line. Then, captured wave patterns of the towing test exhibited a fit visual with the computation, in which Wigley hulls produced a more significant wave than warp-chine hulls.
... The computed instantaneous wave patterns of the overtaking process with γ = 0.3, 0.6 and 0.9 at various values of instantaneous stagger are shown in figure 13. With smaller γ as shown in figure 13a, Hull 1 moves at much slower speeds than the overtaking hull and generates insignificant waves; therefore, its wave patterns are almost imperceptible in comparison with those of Hull 2. As the value of γ approaches one, two hulls generate waves with comparable amplitudes and wavelengths; therefore, more significant wave interference may be achieved which may considerably change the wave elevations of the flow field [24,27,56]. For example, as shown in figure 13c, the transverse ship waves of each hull are of similar wavelengths and heights, and significant increase in wave elevations is observed in-between hulls and behind sterns at nearzero stagger where two sets of ship waves align peak-to-peak. ...
The study on close-quarter manoeuvring of vessels is of great importance for the safety and efficiency of maritime operations. In this paper, the hydrodynamic interactions between two vessels in moderate-speed overtaking manoeuvres are studied. Computational investigation by free-surface panel method is performed, and the results are assessed against experimental measurements from towing-tank model tests. The influences of overtaking speed and the speed difference between vessels on the hydrodynamic loads are studied. It is found that the free-surface deformation, on account of the blockage effects of the bodies, wave-making properties of the vessels, and the interference of unsteady wave patterns between the vessels, considerably affects the hydrodynamic interactions. In addition, it is also discovered that the influence from the unsteady heave and pitch motions of the hulls on the hydrodynamic loads can be non-negligible. Furthermore, it is found that the slower vessel to be overtaken generally experiences larger loads with more variation than the overtaking vessel. The loads on both vessels become more similar to those of a steady-state di-hull system when the speed difference between vessels is small.
... As its name suggests, a multi-hulled is a boat with two or more hulls [25][26][27]. The number of hulls varies from two to five with different arrangements and shapes. ...
This paper presents a review of the developments in the battery powered remote control (RC) boat for various applications. In recent time, RC boat stands no more a mere toy or instrument that is solely used for a hobby. Various researches into the applications of RC boats have been undertaken in recent years and its performance has been a continuous growing concern for society. Many researchers have also exerted strenuous efforts into modifying the shapes and materials that are used to manufacture the boat hull, in order to improve its efficiency. In lieu to this, this paper provides information on different types of boat hulls and their characteristics. Knowing the fact that the performance of the RC boat has been directly affected by its component parts such as the motor, ESC, rudder, propeller and others, the paper highlights an overview of the RC boat's basic components and its setup. Owing to the review works presented, future research is proposed which may open new research pathways to the subject of interest.
... As its name suggests, a multi-hulled is a boat with two or more hulls [25][26][27]. The number of hulls varies from two to five with different arrangements and shapes. ...
This paper presents a review of the developments in the battery powered remote control (RC) boat for various applications. In recent time, RC boat stands no more a mere toy or instrument that is solely used for a hobby. Various researches into the applications of RC boats have been undertaken in recent years and its performance has been a continuous growing concern for society. Many researchers have also exerted strenuous efforts into modifying the shapes and materials that are used to manufacture the boat hull, in order to improve its efficiency. In lieu to this, this paper provides information on different types of boat hulls and their characteristics. Knowing the fact that the performance of the RC boat has been directly affected by its component parts such as the motor, ESC, rudder, propeller and others, the paper highlights an overview of the RC boat’s basic components and its setup. Owing to the review works presented, future research is proposed which may open new research pathways to the subject of interest.
Pentamaran, a vessel with five hulls, can be an alternative for high-speed vessels due to its advantages, for instance, its excellent stability and seakeeping performance and broader deck space than an equivalent monohull with the same displacement. The destructive interference between the system of waves produced by the vessel’s hulls might benefit the reduction of power consumption. This study investigated a Wigley hull form pentamaran model with five asymmetric and symmetric hull configurations and three variations of hull separation. The ship model was towed in conditions of fixed towing and calm water with Froude numbers (Fr) ranging from 0.55 to 1.00. A resistance analysis had been carried out to ensure proper comparison between the asymmetric and symmetric hull configurations. Results showed that total resistance coefficient of the asymmetries created different properties from the symmetries, that is, symmetries produced steadier trends than asymmetries. The hull separation variation caused a slight alteration in the total resistant coefficient (in magnitude) under the same configuration. Although not a single configuration outperformed the others in the entire range of Fr, three configurations were noteworthy as optimum models based on their Fr range. Moreover, a configuration of asymmetric hull with S/L = 0.22 could generate a constant destructive interference throughout the investigated Fr range.
The steady wave patterns, Kelvin-wake spectra and wave resistance of several realistic ship hulls are computed by a Rankine panel method. Wall-sided as well as transom-stern ships are studied over a broad range of Froude numbers and the importance of enforcing a Kutta-type condition of smooth flow detachment at the transom stern is demonstrated. The lack of numerical damping in the solution scheme permits the reliable prediction of the Kelvin wake far from the ship and allows its use in the evaluation of the free wave spectrum. The wave resistance is evaluated by pressure integration as well as momentum conservation and the merits of the latter method are discussed.
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