The Experts below are selected from a list of 495 Experts worldwide ranked by ideXlab platform

Yize Wang - One of the best experts on this subject based on the ideXlab platform.

  • numerical investigations and optimizations of typical submerged box type Floating Breakwaters using sph
    Ocean Engineering, 2020
    Co-Authors: Zhenqing Liu, Yize Wang
    Abstract:

    Abstract Box-type Floating Breakwaters have been studied extensively. However, the examinations of the performances of them with different shapes or different numbers of boxes are limited. In addition, if it is possible to optimize the Floating Breakwaters by combining the optimized parameters in separated testing groups is still unclear. Consequently, in this study, four typical box-type Floating Breakwaters, i.e., dual rectangular breakwater, single rectangular breakwater, dual circular breakwater, and single circular breakwater, are selected to do extensive investigations using SPH. The coupling between DualSPHysics and MoorDyn is implemented and verified, and the coupled code can be applied to simulate the interactions between waves and moored Floating structures. A total of 88 cases are modeled, and the effects of the geometry parameters on wave-attenuation performances of the Breakwaters are clarified. The numerical results show that the performances of the Breakwaters are greatly sensitive to the immersion depth. In general, the larger and lighter the Breakwaters, the better the performances will be. Meanwhile, the dual rectangular breakwater performs the best in wave attenuations, and its motions and forces are smaller than single Breakwaters. Importantly, combining the optimized parameters in each separated testing group is found to be effective to optimize the Floating Breakwaters.

  • numerical studies of submerged moored box type Floating Breakwaters with different shapes of cross sections using sph
    Coastal Engineering, 2020
    Co-Authors: Zhenqing Liu, Yize Wang
    Abstract:

    Abstract The wave-attenuation performances and hydrodynamics of moored box-type Floating Breakwaters with the same weight, same wall thickness, and six different cross-sections, i.e. circular, triangle-down, triangle-up, rectangular, trapezoid-down, and trapezoid-up, are investigated numerically using the smoothed particle hydrodynamics (SPH) method. Coupling between DualSPHysics and MoorDyn is implemented in the coupled SPH-mooring model. The effects of the key parameters, such as the breakwater density, immersion depth, ballast-water gravity, and wave condition, on wave-attenuation performance are examined systematically. The results reveal that the performances of Floating Breakwaters are significantly affected by the immersion depth and wave condition, however, they are hardly affected by density and ballast-water gravity. Furthermore, the top deck is found to be an extremely effective part of a well-designed breakwater, and asymmetrical designs such as longer top-faces and shorter bottom-faces should be adopted for achieving reasonable material utilizations. Irrespective of the shapes of the cross-sections, the best performances of the different Breakwaters are almost at the same level after careful designs are implemented. Importantly, a strong relationship is identified between the motions, mooring tensions, and wave-attenuation performances, which implies that the motions are directly proportional to the wave-attenuation performances and the mooring tensions.

Yong Cheng - One of the best experts on this subject based on the ideXlab platform.

  • experimental study of hydrodynamic performance for double row rectangular Floating Breakwaters with porous plates
    Ships and Offshore Structures, 2019
    Co-Authors: Xiangqian Bian, Yong Cheng, Ke Yang
    Abstract:

    At present, Floating Breakwaters (FBs) have a good attenuating effect on short period wave, but the transmission coefficient of long period wave is still high and single-row FBs usually cannot prov...

  • an experimental study of double row Floating Breakwaters
    Journal of Marine Science and Technology, 2019
    Co-Authors: Xiaokang Deng, Yong Cheng
    Abstract:

    A preliminary experimental study on the hydrodynamic behaviors of double-row Floating Breakwaters is carried out in a wave flume under regular wave action. The Floating breakwater chosen as the experimental subject is a dual rectangular pontoon Floating breakwater. The hydrodynamic behaviors of the Floating breakwater are validated through the calculation of the wave transmission coefficients, the wave reflection coefficients, the motion responses of the Floating Breakwaters and the mooring forces for different waves and structural parameters. The dynamic responses of single-row Floating breakwater as a control group are also examined in the present experiments. The results indicate that double-row Floating Breakwaters significantly reduces the transmission coefficients as compared with single-row Floating breakwater, especially for short-period wave, which is attributed to dissipation caused by eddies and moon-pool effect. However, the reflection performance is almost identical between two types. It is also found that the motion responses of the single-row and double-row Floating Breakwaters are similar. Spacing distance between double-row Floating Breakwaters has a significant influence on the windward mooring tension of the model at the upstream location, which always keeps the largest level in all mooring forces.

Zhiming Yuan - One of the best experts on this subject based on the ideXlab platform.

  • experimental study of a new type of Floating breakwater
    Ocean Engineering, 2015
    Co-Authors: Chunyan Ji, Zhiming Yuan, Xiang Chen, Atilla Incecik
    Abstract:

    A new type of Floating breakwater (FB) is proposed in this paper. Its hydrodynamic performance has been tested. The structure of the new breakwater named cylindrical Floating breakwater (CFB) consists of two parts: a main body of rigid cylinders, and a flexible mesh cage containing a number of suspending balls that are intended to absorb the wave energy into their mechanical energy. A series of experiments were carried out on the new Floating breakwater and traditional double pontoons and box Floating Breakwaters to compare their performances. A two-dimensional wave flume was used in the experiment; the incident and transmitted waves, the tensions on the mooring lines and the motion responses of the Floating Breakwaters were measured. Results showed that the new Floating breakwater had a better performance than the traditional double pontoons and the box Floating Breakwaters: wave transmission was significantly reduced by the mesh cage with the balls, especially for long waves.

  • Experimental study of a hybrid mooring system
    Journal of Marine Science and Technology, 2014
    Co-Authors: Chunyan Ji, Zhiming Yuan
    Abstract:

    Mooring systems are essential to the Floating structures including offshore platforms, wave energy converters and Floating Breakwaters. As Floating structures propagate towards deeper waters, the design of the mooring systems needs to be revamped. In the present study, a new hybrid mooring system has been proposed. A series of weights and buoys are arranged to the different segments of each mooring line in order to improve the motion performance of the platform and eliminate the vertical forces at the lower end of the mooring lines. A series of experiments have been carried out at CSSRC wave basin for a semi-submersible platform moored by the mooring lines with or without the weights and buoys. The mooring lines’ tension and 6-DOF motions of the platform were measured. Discussions have been made on non-linear motion responses of the semi-submersible and non-linear mooring line tension responses for various mooring conditions.

Zhenqing Liu - One of the best experts on this subject based on the ideXlab platform.

  • numerical investigations and optimizations of typical submerged box type Floating Breakwaters using sph
    Ocean Engineering, 2020
    Co-Authors: Zhenqing Liu, Yize Wang
    Abstract:

    Abstract Box-type Floating Breakwaters have been studied extensively. However, the examinations of the performances of them with different shapes or different numbers of boxes are limited. In addition, if it is possible to optimize the Floating Breakwaters by combining the optimized parameters in separated testing groups is still unclear. Consequently, in this study, four typical box-type Floating Breakwaters, i.e., dual rectangular breakwater, single rectangular breakwater, dual circular breakwater, and single circular breakwater, are selected to do extensive investigations using SPH. The coupling between DualSPHysics and MoorDyn is implemented and verified, and the coupled code can be applied to simulate the interactions between waves and moored Floating structures. A total of 88 cases are modeled, and the effects of the geometry parameters on wave-attenuation performances of the Breakwaters are clarified. The numerical results show that the performances of the Breakwaters are greatly sensitive to the immersion depth. In general, the larger and lighter the Breakwaters, the better the performances will be. Meanwhile, the dual rectangular breakwater performs the best in wave attenuations, and its motions and forces are smaller than single Breakwaters. Importantly, combining the optimized parameters in each separated testing group is found to be effective to optimize the Floating Breakwaters.

  • numerical studies of submerged moored box type Floating Breakwaters with different shapes of cross sections using sph
    Coastal Engineering, 2020
    Co-Authors: Zhenqing Liu, Yize Wang
    Abstract:

    Abstract The wave-attenuation performances and hydrodynamics of moored box-type Floating Breakwaters with the same weight, same wall thickness, and six different cross-sections, i.e. circular, triangle-down, triangle-up, rectangular, trapezoid-down, and trapezoid-up, are investigated numerically using the smoothed particle hydrodynamics (SPH) method. Coupling between DualSPHysics and MoorDyn is implemented in the coupled SPH-mooring model. The effects of the key parameters, such as the breakwater density, immersion depth, ballast-water gravity, and wave condition, on wave-attenuation performance are examined systematically. The results reveal that the performances of Floating Breakwaters are significantly affected by the immersion depth and wave condition, however, they are hardly affected by density and ballast-water gravity. Furthermore, the top deck is found to be an extremely effective part of a well-designed breakwater, and asymmetrical designs such as longer top-faces and shorter bottom-faces should be adopted for achieving reasonable material utilizations. Irrespective of the shapes of the cross-sections, the best performances of the different Breakwaters are almost at the same level after careful designs are implemented. Importantly, a strong relationship is identified between the motions, mooring tensions, and wave-attenuation performances, which implies that the motions are directly proportional to the wave-attenuation performances and the mooring tensions.

Karsten Lindegaard Jensen - One of the best experts on this subject based on the ideXlab platform.

  • an experimental and numerical study of Floating Breakwaters
    Coastal Engineering, 2018
    Co-Authors: Erik Damgaard Christensen, Harry B Bingham, Andreas Peter Skou Friis, Alexander Kruse Larsen, Karsten Lindegaard Jensen
    Abstract:

    Abstract Breakwaters are used to provide sheltered areas for loading and unloading of ships, and coastal protection. Often the Breakwaters are bottom mounted such as rubble mound Breakwaters. However, there can be several advantages to use a Floating Breakwater (FB). Therefore, the objective of this paper is to study the effect of two different damping mechanisms of a Floating breakwater. Three basic cross-sections of FBs were tested and analysed in 2D; a regular pontoon (RG), a regular pontoon with wing plates attached (WP), and a regular pontoon with wing plates and porous media attached to the sides (WP P100). The damping of the FB motions was due to wave radiation and viscous damping. The viscous damping originated mainly from vortex generation around the edges of the structure and due to energy loss inside the porous material attached to the vertical sides of the Floating breakwater. Attaching wing plates to the Floating breakwater significantly reduced the motion, which was also anticipated. When the porous sides were attached the motion of the FB increased compared to the (WP) cross-section, but the wave transmission was reduced. The possibility for incorporating the effect of the damping in the radiation/diffraction code WAMIT was assessed. The study showed that the cross section with wing plates reduced the motions of the breakwater to the largest extend, while the cross section with wing plates and porous media attached to the sides reduced the reflection and transmission most effectively.