scholarly journals An Experimental Study on the Motion Response of a High-Speed Planing Craft in Regular Head Waves

2009 ◽  
Vol 46 (4) ◽  
pp. 373-381 ◽  
Author(s):  
Dong-Jin Kim ◽  
Key-Pyo Rhee ◽  
Seung-Hyun Hwang ◽  
Han-Sol Park
2014 ◽  
Vol 88 ◽  
pp. 186-193 ◽  
Author(s):  
N. Santoro ◽  
E. Begovic ◽  
C. Bertorello ◽  
A. Bove ◽  
S. De Rosa ◽  
...  

2020 ◽  
Vol 162 (A1) ◽  
Author(s):  
L Nowruzi ◽  
H Enshaei ◽  
J Lavroff ◽  
S S Kianejad ◽  
M R Davis

CFD has proved to be an effective method in solving unsteady Reynolds–Averaged Navier-Stokes (RANS) equations for analysing ships in free surface viscous flow. The research reported in this paper is intended to develop a better understanding of the parameters influencing high-speed trimaran motions responses. Variations of gridding system and time step have been investigated and reliability analysis was performed in solving the RANS equations. Different turbulence models were investigated, and the SST Menter K Omega turbulence model proved a more accurate model than Realizable K-epsilon model. In order to validate the CFD method, the results of the motions response of a highspeed trimaran are compared against a set of experimental and numerical results from a 1.6 m trimaran model tested in various head seas conditions. The results suggest that CFD offers a reliable method for predicting pitch and heave motions of trimarans in regular head waves when compared to traditional low speed strip theory methods. Unlike strip theory, the effect of breaking waves, hull shape above waterline and green seas are considered in CFD application. A wave resonance phenomenon was observed and wave deformation as a result of wave-current-wind interaction in CFD was identified as the main source of discrepancy. The results from this work form the basis for future analysis of trimaran motions in oblique seas for developing a better understanding of the parameters influencing the seakeeping response, as well as passenger comfort.


2014 ◽  
Vol 66 (2) ◽  
Author(s):  
S. Ikezoe ◽  
N. Hirata ◽  
H. Yasukawa

To capture the seakeeping performance of a catamaran with asymmetric demi-hulls, tank tests were carried out in regular head waves using a scaled model with 2.036 m in length. The lateral space between the demi-hulls was changed in the tests as W/B=2.55, 2.90 and 3.25, where W denotes breadth overall and B the breadth of the demi-hull. Also, two models with different water lines of inside flat and outside round (IF-type) and of outside flat and inside round (OF-type) were used. OF-type is superior to IF-type in both ship motion and added resistance performances in waves at the design speed. In IF-type series, the smallest clearance, W/B=2.55 is the best in the added resistance performance.


2016 ◽  
Vol 158 (B1) ◽  
Author(s):  
E Begovic ◽  
C Bertorello ◽  
A Bove ◽  
S De Rosa ◽  
E Fasano ◽  
...  

This paper presents an experimental research for the assessment of pressure field on the bottom of a mono-hedral hard chine hull at high relative speed. Tests have been performed in rough sea for two wave lengths at Fn ranging from 0.79 to 1.46. The measured pressures have been analysed in time and in frequency domain. The pressure distribution along a rectangular panel of the hull bottom has been identified. The comparison of measured values and those ones provided by Classification Societies has been performed and pressure results have been used to investigate the interactions between the fluid and the craft structure. The elastic behaviour of different bottom panels is analysed, and the scantling of a typical bottom panel, made from four materials, have been calculated, in order to investigate the structural dynamic behaviour.


2008 ◽  
Vol 52 (01) ◽  
pp. 71-86
Author(s):  
Daniele Dessi ◽  
Riccardo Mariani

In recent years, an important trend in the shipbuilding industry has been the increase in the length and speed of high-speed crafts, thus demanding lighter structures. High-speed vehicles with their increased flexibility are more likely to be excited by impulsive loads, such as slamming, which has been extensively studied and discussed by the scientific community. Nevertheless, ship design still demands plain and reliable procedures (numerical and/or experimental) to evaluate the time-dependent global loads in structural dynamics. In this paper, the aim is to explore the possibility of combining the conservation of fluid momentum with the two-dimensional numerical estimation of the effective wetted length in order to improve the prediction of the impact loads without losing the simplicity and efficiency of analytical methods. In order to evaluate the prediction capability of the proposed formulation, the numerical computation of the slamming force is based on processing the model test data relative to the incoming waves and rigid-body motion, and the attained results are compared with the hydrodynamic force experimentally identified. The presented analysis is applied to the slamming tests in regular head waves of a segmented model, supported by an elastically scaled beam, of a fast ferry. By using the slamming load obtained with the theoretical model, the elastic response in terms of bending moments is computed and compared with that provided by direct measurement with strain gauges. Finally, the uncertainty analysis relative to both numerical and experimental results is performed.


Author(s):  
L Nowruzi ◽  
H Enshaei ◽  
J Lavroff ◽  
S S Kianejad ◽  
M R Davis

CFD has proved to be an effective method in solving unsteady Reynolds–Averaged Navier-Stokes (RANS) equations for analysing ships in free surface viscous flow. The research reported in this paper is intended to develop a better understanding of the parameters influencing high-speed trimaran motions responses. Variations of gridding system and time step have been investigated and reliability analysis was performed in solving the RANS equations. Different turbulence models were investigated, and the SST Menter K Omega turbulence model proved a more accurate model than Realizable K-epsilon model. In order to validate the CFD method, the results of the motions response of a high- speed trimaran are compared against a set of experimental and numerical results from a 1.6 m trimaran model tested in various head seas conditions. The results suggest that CFD offers a reliable method for predicting pitch and heave motions of trimarans in regular head waves when compared to traditional low speed strip theory methods. Unlike strip theory, the effect of breaking waves, hull shape above waterline and green seas are considered in CFD application. A wave resonance phenomenon was observed and wave deformation as a result of wave-current-wind interaction in CFD was identified as the main source of discrepancy. The results from this work form the basis for future analysis of trimaran motions in oblique seas for developing a better understanding of the parameters influencing the seakeeping response, as well as passenger comfort.


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