This paper presents a two-dimensional simulation model for the idealisation of moored rectangular and trapezoidal floating breakwaters (FB) motions in regular and irregular waves. Fast-Fictitious D...

https://www.tandfonline.com/doi/pdf/10.1080/17445302.2021.1927358

A machine learning method for the evaluation of hydrodynamic performance of floating breakwaters in waves

Hydrodynamic performance of a new box-type breakwater with superstructure: Experimental study and SPH simulation

Numerical simulation of the wave dissipation performance of floating box-type breakwaters under long-period waves

The invention provides a retractable apron structure of an amphibious aircraft. The retractable apron structure comprises an apron structure and a capsule body retracting device. The apron structure comprises an arc-shaped rigid surface and a capsule body, wherein one end of the arc-shaped rigid surface is hinged to a hull, the other end of the arc-shaped rigid surface is hinged to the capsule body, the capsule body is further hinged to the bottom of the hull, and an exhaust hole channel is arranged at the joint between the capsule body and an air chamber. The capsule body retracting device comprises a connecting rope, a miniature electric hoist and a connecting piece, wherein the miniature electric hoist is arranged at the top end of the air chamber, the connecting piece is arranged on the capsule body, the connecting piece is connected to one end of the connecting rope, and the miniature electric hoist is connected to the other end of the connecting rope. The retractable apron structure of the amphibious aircraft is simple in structure, easy to operate and convenient to inspect and maintain, and can well adapt to two working conditions of an air cushion aircraft, the response ofthe apron structure is higher during sailing at sea, and the seakeeping is good; and the retractable apron design can reduce the flying resistance during flying, and the air cushion aircraft is enabled to have better navigation performance.

Retractable apron structure of amphibious aircraft

Hydrodynamic Performance of Fixed Floating Structures Coupled with Submerged Breakwaters Using the Multidomain Boundary Element Method

An experimental investigation on the hydrodynamic performance of a box-floating breakwater in different terrains is performed in a 2D wave flume under regular wave actions and irregular wave actions, respectively. The wave transmission coefficients, motion responses and mooring forces are focused to validate the hydrodynamic performance of the box-floating breakwater. The performance of the box-floating breakwater in flat terrain is also experimentally investigated for comparison. The influences of the terrain width and quantity on the hydrodynamic behaviors of the box-floating breakwater are discussed and analyzed. The results indicate that the box-floating breakwater in different terrains has a better wave attenuating ability than the box-floating breakwater in flat terrain due to wave energy loss caused by the interaction between the breakwater and terrain. However, the width of terrain has a limited effect on the hydrodynamic performance of the floating breakwater. For double terrains, the wave attenuation performance of the box-type floating breakwater increases with the decrease of the spacing between double terrains, especially for long-period waves. It is also found that terrain has significant influences on the roll and heave motions, while terrain hardly affects the sway motions. In addition, terrain plays an important role in the mooring forces, while the width and quantity of terrain weakly affect the mooring forces of box-floating breakwater. To investigate the hydrodynamic performance of rectangular floating breakwater in different terrains systematically, Smoothed Particle Hydrodynamics (SPH) methods is used. It can be concluded that the results of SPH show a good agreement with the experimental results.

An experimental study on hydrodynamic performance of a box-floating breakwater in different terrains

The invention relates to a landing craft with an embedded and retractable air cushion. The landing craft with the embedded and retractable air cushion is characterized in that the landing craft comprises a main craft body, a craft body superstructure, an embedded and retractable airbag cabin, water jet propulsion devices and vector air propeller devices; when hover draught fans work, a part of airflows to an airbag through a telescopic pipe, then flows into a corresponding pressurizing branch room through flow dividing cabin doors, and finally enters an air cushion cabin through a plurality of openings formed in the bottoms of the pressurizing branch rooms to form an air cushion; and a part of air flows directly to the pressurizing branch rooms through the telescopic pipe, and then entersthe air cushion cabin through the openings formed in the bottoms of the pressurizing branch rooms to form the air cushion. When the pressure intensity in the airbag reaches a certain value, a craft body is supported by the air cushion, the craft body is made to separate away from the water surface by the air cushion, and the resistance is greatly reduced; and at the same time, the landing craft has the ability of walking on a road, when the pressure in the airbag reaches a design value, the craft body is separated away from the water surface to form the air cushion, and air propellers on therear parts of connecting axles can provide power and steering in the horizontal direction. According to the navigation mode, human and material resources can be transported to a specified region in ashort time.

Hui Liu

Papers

An experimental study on hydrodynamic performance of a box-floating breakwater in different terrains

Landing craft with embedded and retractable air cushion