The hydrodynamic characteristics of a single suspended row of half pipes under regular waves

2012 ◽  
Vol 50 ◽  
pp. 1-9 ◽  
Author(s):  
A.S. Koraim ◽  
T.N. Salem
Keyword(s):  
Hydrodynamic Characteristics ◽  
Regular Waves

Experimental Study on Hydrodynamics of Hybrid Deep-V Monohull With Different Built-Up Appendages

2018 ◽  
Author(s):  
Shuzheng Sun ◽  
Hui Li ◽  
Muk Chen Ong
Keyword(s):  
Model Test ◽  
Performance Model ◽  
Hydrodynamic Performance ◽  
Irregular Waves ◽  
Hydrodynamic Characteristics ◽  
Vertical Acceleration ◽  
Test Results ◽  
Regular Waves ◽  
Sea State ◽  
Seakeeping Performance

The hydrodynamic characteristics of a hybrid deep-V monohull with different built-up appendages are investigated experimentally in order to improve the resistance and seakeeping performance. Model tests have been carried out to study the hydrodynamic performance between a bare deep-V vessel and a deep-V monohull with different built-up appendage configurations (i.e. a hybrid deep-V monohull). From the model test results, it is found that the existence of the appendages will reduce the amplitude of pitching angle and bow vertical acceleration compared to that of the bare deep-V vessel in heading regular waves. However, the resistances for the hybrid deep-V monohull with built-up appendages are increased 15.6% for Fn = 0.264, and 0.1% for Fn = 0.441 compared to the resistance of the bare deep-V vessel. The model test results of seakeeping performance in irregular waves show that the hybrid deep-V monohull gives a better seakeeping performance than the deep-V vessel. The pitching angle and bow vertical acceleration of the hybrid deep-V monohull containing a built-up appendage are reduced 15.3% and 20.6% compared to the deep-V monohull in irregular waves at Fn = 0.441 in 6th class sea state (H1/3 = 6m).

A Finite Element Model for Efficiency of a Moored Floating OWC Device in Regular Waves

2011 ◽  
Author(s):  
Jean-Roch Nader ◽  
Song-Ping Zhu ◽  
Paul Cooper ◽  
Brad Stappenbelt
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Wave Theory ◽  
Element Model ◽  
Energy Output ◽  
Chamber Pressure ◽  
Hydrodynamic Characteristics ◽  
Linear Wave ◽  
Regular Waves ◽  
Restoring Force

Hydrodynamic characteristics of floating OWC can be quite difficult to predict especially when a strong coupling is present between the chamber pressure and the device movements. Mooring properties, and air pressure inside the chamber can also considerably influence the motion of the device and therefore the energy output. A newly developed 3D finite element model based on the linear wave theory has been applied to a cylindrical type OWC device. The study focused principally on the effects of the mooring restoring force and pressure pneumatic damping in the chamber total volume flux and energy conversion of the device. Results show that properly chosen parameters could effectively increase the efficiency band width of such devices.

Regular Wave Experiments for Twin Circular Submerged Floating Tunnel Tethered to Sea Bottom

2017 ◽  
Author(s):  
Sang-Ho Oh ◽  
Woo Sun Park
Keyword(s):  
Hydrodynamic Performance ◽  
Hydrodynamic Characteristics ◽  
Two Dimensional ◽  
Wave Loading ◽  
Regular Waves ◽  
Wave Flume ◽  
Sea Bottom ◽  
Physical Experiments ◽  
Tensile Forces ◽  
Submerged Floating Tunnel

Assessment of hydrodynamic performance of submerged floating tunnel (SFT) under wave loading is one of important factor in the design of the structure. In this study, physical experiments were conducted in a two-dimensional wave flume to investigate hydrodynamic characteristics of a twin circular SFT model under the action of regular waves having different heights and periods. Five different configurations of the twin SFT model was tested in the experiment. The experimental results showed that the three-degree motions of the twin SFT and the associated tensile forces on the tension legs greatly vary with the configurations of the model. It was found that the CD0 configurations are most adequate for satisfactorily restricting the horizontal and vertical motions of the SFT model.

Hydrodynamic Characteristics of Curved-Front Seawall Models Compared with Vertical Seawall under Regular Waves

2011 ◽  
Vol 277 ◽  
pp. 1103-1112 ◽  
Author(s):  
Karur Vaideeswaran Anand ◽  
Vallam Sundar ◽  
Sannasi Annamalaisamy Sannasiraj
Keyword(s):  
Hydrodynamic Characteristics ◽  
Regular Waves

scholarly journals Computational and experimental determination of waterjet aeration exposure in waves

2020 ◽  
Vol 4 (394) ◽  
pp. 21-30
Author(s):  
Tatyana A. Dyakova ◽  
Sergey O. Rozhdestvensky ◽  
Nikolai V. Marinich ◽  
Alexey A. Rudnichenko
Keyword(s):  
Numerical Simulation ◽  
Video Camera ◽  
Full Scale ◽  
Irregular Waves ◽  
Head Wave ◽  
Hydrodynamic Characteristics ◽  
Regular Waves ◽  
Seakeeping Performance ◽  
Calm Water ◽  
Air Penetration

Object and purpose of research. The object of research was a model of a fast seaworthy boat with discretevariable bottom deadrise and two waterjet propulsors. The purposes of research were to experimentally determine hydrodynamic characteristics of the model in calm water and head regular waves corresponding to the irregular waves of sea states 3 and 4, as well as to determine the possibility of air penetration to waterjet inlets for two variants of their arrangement on model bottom in head-wave conditions, numerical simulation of the full-scale boat movement in oblique irregular waves (sea state 4) for two variants of waterjet arrangement, with an assessment of waterjet duct aeration exposure. Materials and methods. Model hydrodynamics was estimated experimentally by means of towing tests in highspeed seakeeping basin in calm water and head regular waves using standard test equipment; air penetrations were recorded by a GO PRO digital video camera installed on the model above the water inlets. Numerical simulation of the full-scale boat movement was carried out in Star-CCM+ CFD package. Main results. The study yielded the curves of towing resistance, running trim and sinkage versus model speed in calm water and head regular waves of different length for two longitudinal CG positions, as well as the areas of air penetration to waterjet inlets on model bottom. Analysis of the experimental data enabled the estimation of attainable speed for the boat with displacement of 50 and 29 tf in waves for given delivered power. Numerical simulation of the full-scale boat movement in oblique irregular waves for two variants of waterjet arrangement has also been carried out. Conclusion. The results have shown that seakeeping performance of the boat is quite satisfactory and that the most obvious way to mitigate air penetrations is to reduce the speed. Other important factors were shifting the waterjet inlet towards the transom and to the CL, as well as shifting the longitudinal CG forward. The obtained results can be used to select the position of the waterjet inlets on boat bottom in order to increase waterjet efficiency. Using the methods of numerical hydrodynamics, the characteristics of the waterjets have been obtained, the probability and volumes of air penetrations to waterjet ducts (for different variants of waterjet arrangement) at several angles of oblique irregular waves have been estimated.

Hydrodynamic characteristics of double permeable breakwater under regular waves

2011 ◽  
Vol 24 (4) ◽  
pp. 503-527 ◽  
Author(s):  
A.S. Koraim ◽  
E.M. Heikal ◽  
O.S. Rageh
Keyword(s):  
Hydrodynamic Characteristics ◽  
Regular Waves

Time-domain numerical research of the hydrodynamic characteristics of a trimaran in calm water and regular waves

2019 ◽  
Vol 194 ◽  
pp. 106669
Author(s):  
Rui Deng ◽  
Fuqiang Luo ◽  
Tiecheng Wu ◽  
Siyuan Chen ◽  
Yulong Li
Keyword(s):  
Time Domain ◽  
Hydrodynamic Characteristics ◽  
Regular Waves ◽  
Calm Water ◽  
Numerical Research

Hydrodynamic Characteristics of Submerged Impermeable and Seaside Perforated Semicircular Breakwaters

2002 ◽  
Author(s):  
Govindasamy Dhinakaran ◽  
Vallam Sundar ◽  
Renganathan Sundaravadivelu ◽  
Kai-Uwe Graw
Keyword(s):  
Surface Area ◽  
Water Depth ◽  
Hydrodynamic Characteristics ◽  
Transmission Characteristics ◽  
Regular Waves ◽  
Scattering Parameter ◽  
Reflection And Transmission ◽  
Total Height ◽  
Semicircular Breakwater

The semicircular breakwater (SBW) is one of the varieties of breakwaters, which has emerged recently. The world’s first semicircular breakwater has been constructed at Miyazaki port in Japan. The dynamic pressures due to regular waves exerted on a SBW with 7% of its seaside surface area with perforations were measured. The variations of dimensionless pressures for three different water depth (hw) to total height of the model (ht), ratios are presented and discussed in this paper. In addition, the reflection and transmission characteristics of the perforated SBW as a function of scattering parameter, ka is reported. The results on the above stated variables for a seaside perforated SBW are compared with the results for an impermeable SBW.

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