Hydrodynamic Performance of a Deep-Vee Hull Form Catamaran in Regular Waves

2011 ◽  
Author(s):  
Musa B. Bashir ◽  
Longbin Tao ◽  
Mehmet Atlar ◽  
Robert S. Dow
Keyword(s):  
National Physical Laboratory ◽  
Hydrodynamic Performance ◽  
Regular Waves ◽  
Hull Form ◽  
Towing Tank ◽  
Geometrical Properties ◽  
Physical Laboratory ◽  
Motion Measurements ◽  
Motion Characteristics ◽  
Hull Forms

This paper presents the results of experiments carried out to determine the motion/seakeeping behavior of a deep-vee hull form catamaran in regular sea condition. A deep-vee catamaran model for the Newcastle University’s new RV replacing the old RV Bernicia was used for the motion measurements. The experiments were performed in the university’s towing tank. The results obtained were validated using a 3D panel method in frequency domain. A comparison of these results with the motion characteristics of the NPL (National Physical Laboratory) round bilge hullform based catamaran of similar geometrical properties revealed that the deep-vee hull forms possess significantly better seakeeping capabilities than a round bilge hull form.

Geometrical Variation and Distortion of Ship Hull Forms

2003 ◽  
Vol 40 (04) ◽  
pp. 239-248
Author(s):  
Ebru Narh ◽  
Kadir Sariöz
Keyword(s):  
Computer Aided Design ◽  
Ship Hull ◽  
Hydrodynamic Performance ◽  
Hull Form ◽  
Nonlinear Distortions ◽  
Form Design ◽  
Hull Form Design ◽  
Geometrical Variation ◽  
Hull Forms ◽  
Aided Design

Because of the risk involved with starting the hull form design from scratch, the designer most frequently initiates the hull form design process with a parent form that has satisfactory hydrodynamic performance. Hence, linear and nonlinear variation and distortion techniques have found wide applications in the hull form design studies. Some of these methods are simple and easy to apply by practicing naval architects, whereas others may be considered too complicated and difficult to use without simplifications. Existing and emerging techniques to distort a parent ship hull form are discussed and applied to a typical ship form. These techniques range from a simple one minus prismatic method to complex nonlinear distortions and include emerging computer-aided design (CAD) methods, such as shape averaging. The applications indicate that the techniques presented can be safely applied to conventional ship hull forms. The advantages and drawbacks of these methods are discussed, and numerical results are presented.

Experimental and Numerical Investigation of the Wave-Induced Loads on a Deep-V Catamaran in Regular Waves

2013 ◽  
Author(s):  
Musa B. Bashir ◽  
Longbin Tao ◽  
Mehmet Atlar ◽  
Robert S. Dow
Keyword(s):  
Wave Loads ◽  
Forward Speed ◽  
Regular Waves ◽  
Hull Form ◽  
Proper Understanding ◽  
Towing Tank ◽  
Centre Of Gravity ◽  
Numerical Predictions ◽  
New Research ◽  
Wave Induced

This paper presents the results of towing tank tests carried out to predict the wave loads in regular wave conditions on a Deep-V hull form catamaran model. The experiments were carried out at the Newcastle University towing tank using a segmented model of the university’s new research vessel, “The Princess Royal”. The vessel is a twin hull with a Deep-V shape cross-section. The model, divided into two parts at the cross-deck level, was fitted with a 5-axis load cell at the position of the vessel’s centre of gravity in order to measure the motions response and wave loads due to the encountered waves. The longitudinal, side and vertical forces, along with the prying and yaw splitting moments were measured. The results obtained were further compared with those from numerical predictions carried out using a 3D panel method code based on potential flow theory that uses Green’s Function with the forward speed correction in the frequency domain. The results highlight reasonable correlations between the measurements and the predictions as well as the need for a proper understanding of the response of the multihull vessels to the wave-induced loads due to the non-linearity that have been observed in the experimental measurements of wave loads.

Hull Form Optimization for Hydrodynamic Performance

2004 ◽  
Vol 41 (04) ◽  
pp. 167-182
Author(s):  
Gregory J. Grigoropoulos
Keyword(s):  
Water Resistance ◽  
Optimization Procedure ◽  
Hydrodynamic Performance ◽  
Hull Form ◽  
Principal Characteristics ◽  
Calm Water ◽  
Rough Water ◽  
Hull Forms ◽  
Scaled Models ◽  
Formal Optimization

A method for optimizing hull forms with respect to their hydrodynamic performance in calm and rough water is presented. The method is based on an initial optimization of a parent hull form for seakeeping and the improvement of the resulting optimum hull form for calm water resistance. In the first part of the method, variant hull forms differing from a parent in the main dimensions and/or in one or more hull form parameters, such as CWP, LCF, CB, LCB, KB, CP, are automatically generated and their seakeeping qualities evaluated. When appropriate ranges for the principal characteristics and parameters of the hull form under investigation are prescribed, a formal optimization procedure is used to obtain the variant with the best seakeeping behavior. The weighted sum of the resonant values of selected ship responses for a number of ship speeds and headings in regular waves forms the objective function. The Hooke and Jeeves algorithm is used to accomplish the optimization. The procedure results in a set of trends regarding the proposed variations of the selected hull form parameters, within the specified constraints. These trends are then applied on the parent hull to derive an optimized hull form with fair lines. Subsequently, this hull form can be locally modified to improve its calm water resistance or, as it should be done, its propulsion characteristics. The applicability of the method is demonstrated in two cases: a conventional reefer ship and a naval destroyer. Scaled models of the parent and the optimized hull forms have been tested for calm water resistance and seakeeping. In both cases the validity of the methodology is demonstrated.

Effect of Inverted Bow on the Hydrodynamic Performance of Navy Combatant Hull Forms

2015 ◽  
Author(s):  
Jeffrey K. White ◽  
Stefano Brizzolara ◽  
William Beaver
Keyword(s):  
Hydrodynamic Performance ◽  
Parametric Surfaces ◽  
Regular Waves ◽  
Scale Models ◽  
Calm Water ◽  
Vertical Accelerations ◽  
Hull Forms

In this paper we investigate the resistance and seakeeping effects of an inverted bow by comparing the motions of an existing combatant hull, the Oliver Hazard Perry class frigate (FFG-7), with a modified version of the hull with an inverted bow. The bow of the FFG-7 was redesigned by developing a set of basic curves that define the parametric surfaces of the new shape. Two 1/80th scale models were tested for resistance in calm water and seakeeping in both regular waves and irregular head seas. The differences between the FFG-7 and the inverted bow responses are characterized in terms of pitch and heave motions and vertical accelerations.

scholarly journals WAVE-INDUCED LOADS ON CROSS-DECK OF A WAVE-PIERCING TRIMARAN WITH DIFFERENT HULL FORMS OF OUTRIGGERS

Transport ◽  
2019 ◽  
Vol 34 (5) ◽  
pp. 559-568
Author(s):  
Abolfath Askarian Khoob ◽  
Mohammad Javad Ketabdari
Keyword(s):  
Potential Flow ◽  
Wave Loads ◽  
Forward Speed ◽  
Regular Waves ◽  
Hull Form ◽  
High Speeds ◽  
Complex Structural ◽  
Hull Forms ◽  
Wave Induced ◽  
Study Offer

Trimaran has unique hull form with a rapidly growth in recent years due to its application as a mode of transports and naval vessels. Designing trimaran faces many technical challenges because of its complex structural outlines and high-speeds operation. This article investigates the influence of side hulls configuration (symmetric, inboard and outboard types) for wave loads on cross-deck of a trimaran ship when advancing at sea in regular waves. The computation of these hydrodynamic forces is carried out using MAESTRO-Wave 3D panel method code. This code is based on potential flow theory that uses Green’s function with the forward speed correction in the frequency domain. The results demonstrate that the outboard side hull form has the best performance on wave-induced load among three kinds of side hull forms. Furthermore, the results of this study offer more information for selecting the side hull form of the trimaran.

scholarly journals 75th Foundation Day of CSIR-National Physical Laboratory: Celebration of Achievements in Metrology for National Growth

MAPAN ◽  
2021 ◽  
Author(s):  
Sanjay Yadav ◽  
Goutam Mandal ◽  
V. K. Jaiswal ◽  
D. D. Shivagan ◽  
D. K. Aswal
Keyword(s):  
National Physical Laboratory ◽  
Physical Laboratory ◽  
National Growth

Study on vertical motion reduction of a trimaran based on collaborative controlled appendages

2020 ◽  
Vol 17 (6) ◽  
pp. 172988142097677
Author(s):  
Zhilin Liu ◽  
Linhe Zheng ◽  
Guosheng Li ◽  
Shouzheng Yuan ◽  
Songbai Yang
Keyword(s):  
Experimental Study ◽  
Vertical Motion ◽  
Model Tests ◽  
Wave Period ◽  
Regular Waves ◽  
Towing Tank ◽  
Vertical Stability ◽  
Stabilization Control ◽  
Stability Performance

In recent years, the trimaran as a novel ship has been greatly developed. The subsequent large vertical motion needs to be studied and resolved. In this article, an experimental study for a trimaran vertical stabilization control is carried out. Three modes including the bare trimaran (the trimaran without appendages, the trimaran with fixed appendages, and the trimaran with controlled appendages) are performed through model tests in a towing tank. The model tests are performed in regular waves. The range of wave period is 2.0–4.0 s, and the speed of the carriage is 2.93 and 6.51 m/s. The results of the three modes show the fixed appendages and the actively controlled appendages are all effective for the vertical motion reduction of the trimaran. Moreover, the controlled appendages are more effective for the vertical stability performance of the trimaran.

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