scholarly journals Slit-type Breakwater; Box-type Wave Absorber

1976 ◽  
Vol 1 (15) ◽  
pp. 154 ◽  
Author(s):  
Shoshichiro Nagai ◽  
Shohachi Kakuno
Keyword(s):  
Cross Section ◽  
Water Depth ◽  
Vertical Wall ◽  
Bottom Wall ◽  
Front Wall ◽  
Type Wave ◽  
Composite Type ◽  
New Type ◽  
Vertical Walls ◽  
Horizontal Bottom

A box-type wave absorber, which is composed of a perforated vertical front-wall and a perforated, horizontal bottom-wall, has been proved by a number of experiments to show lower coefficients of reflection and more distinguished reduction of wave pressures than the perforated vertical- wall breakwater. A breakwater of composite-type, which is 1500 m long and to be built at a water depth of 10 to 11 m below the Datum Line in the Port of Osaka, is being designed to set this new type of wave absorber in the concrete caissons of the vertical-walls which is named "a slit-type breakwater". The typical cross-section of the breakwater and the advantages of the slit-type breakwater are presented herein.

scholarly journals Study on mechanical properties of a new type of prefabricated GRC mold shell

2019 ◽  
Vol 136 ◽  
pp. 02030
Author(s):  
Chen Dong ◽  
Chen Ming ◽  
Cai Ouyang ◽  
Li Pengkun
Keyword(s):  
Mechanical Properties ◽  
Production Process ◽  
Cross Section ◽  
Stress System ◽  
Research Results ◽  
Floor Space ◽  
Section Size ◽  
Speed Up ◽  
New Type ◽  
Prefabricated Building

The GRC formwork structural column adopts the factory-based vertical prefabrication production process, which can reduce the floor space, reduce the formwork loss, speed up the construction progress, promote the full decoration of the prefabricated building, and improve the efficiency of the assembly construction. major. In order to optimize the production process of prefabricated GRC formwork column, the overall stress system of GRC formwork structure is analyzed in the concrete pouring process, and the thickness of GRC formwork, the number of steel hoops and the GRC mode are considered. The influence of the shell cross-section size on the mechanical properties. The research results can provide reference for the optimization and design of prefabricated GRC formwork column production process.

A new type of 3D [(MII)2(TCNQ−II)3]2−coordination network with spacious channels of hexagonal cross-section generated from TCNQH2

CrystEngComm ◽  
2012 ◽  
Vol 14 (2) ◽  
pp. 351-354 ◽  
Author(s):  
Brendan F. Abrahams ◽  
Robert W. Elliott ◽  
Timothy A. Hudson ◽  
Richard Robson
Keyword(s):  
Cross Section ◽  
Coordination Network ◽  
Hexagonal Cross Section ◽  
New Type

The Influence of Volume Surface Ratio of Rectangle Air-Conditioning Duct on Particle Deposition

2011 ◽  
Vol 71-78 ◽  
pp. 3633-3638 ◽  
Author(s):  
Jie Zhang ◽  
Ze Hua Liu ◽  
Yuan Quan Liu ◽  
Hui Min Li ◽  
Yong Fei Ning
Keyword(s):  
Cross Section ◽  
Air Conditioning ◽  
Particle Deposition ◽  
Deposition Velocity ◽  
Vertical Wall ◽  
Influence Factors ◽  
Particle Model ◽  
Random Trajectory ◽  
Air Speed ◽  
The Given

This paper discusses particle deposition in rectangle air-conditioning duct using RSM (Reynold Stress Model) and random trajectory particle model. Particle with nominal diameters of 10-200μm are simulated at each of three nominal air speed: 4m/s, 6m/s and 8m/s, respectively, in the cross-section sizes of 160×120, 500×250, 1000×320mm. In simulation, the paper compares and analyzes the influence factors of particles deposition in volume surface ratio of the given duct. The results show that: 1) particle deposition velocity increases with volume surface ratio; 2) As the inlet air speed increasing, when the particles deposited to floor and vertical wall, the image of dimensionless deposition velocity Vs dimensionless relaxation time shows a coincident trend when the duct cross-section sizes are 500×250, 1000×320mm, but has great differences with the image of 160×120mm.

Hydrodynamic Properties of an Asymmetric Deepwater Riser Bundle

2006 ◽  
Author(s):  
Charles Zimmermann ◽  
Richard James ◽  
Blaise Seguin ◽  
Mattias Lynch
Keyword(s):  
Cross Section ◽  
Water Depth ◽  
Hydrodynamic Characteristics ◽  
Cfd Analysis ◽  
Effective Solution ◽  
Hydrodynamic Properties ◽  
Global System ◽  
Field Development ◽  
Hydrodynamic Behaviour ◽  
Deepwater Riser

The BP operated Greater Plutonio field development offshore Angola comprises a spread-moored FPSO in 1,300 m water depth, serving as a hub processing the fluids produced from or injected into the subsea wells. The selected riser system is a riser tower tensioned by a steel buoyancy tank at its top end and distributed foam buoyancy along a central structural tubular. The riser bundle is asymmetric in cross-section and this paper presents the work performed to determine the specific hydrodynamic characteristics of the design. Both basin tests and CFD analysis results are presented with discussion on some specific hydrodynamic issues: vortex-induced vibration (VIV) of the global riser tower system, VIV of individual risers, and the dynamic stability of the global system (i.e. galloping). Finally, guidelines for the assessment of the hydrodynamic behaviour of such system geometries are proposed. The results of this paper demonstrate that the Greater Plutonio riser bundle represents an effective solution in term of hydrodynamic behaviour and is not sensitive to VIV fatigue or galloping.

Validation of Wave Propagation in Numerical Wave Tanks

2005 ◽  
Author(s):  
Tim Bunnik ◽  
Rene´ Huijsmans
Keyword(s):  
Shallow Water ◽  
Model Test ◽  
Water Depth ◽  
Linear Potential ◽  
Intermediate Water ◽  
Numerical Wave Tank ◽  
Wave Tank ◽  
Type Wave ◽  
Wave Generator ◽  
Numerical Wave

During the last few years there has been a strong growth in the availability and capabilities of numerical wave tanks. In order to assess the accuracy of such methods, a validation study was carried out. The study focuses on two types of numerical wave tanks: 1. A numerical wave tank based a non-linear potential flow algorithm. 2. A numerical wave tank based on a Volume of Fluid algorithm. The first algorithm uses a structured grid with triangular elements and a surface tracking technique. The second algorithm uses a structured, Cartesian grid and a surface capturing technique. Validation material is available by means of waves measured at multiple locations in two different model test basins. The first method is capable of generating waves up to the break limit. Wave absorption is therefore modeled by means of a numerical beach and not by mean of the parabolic beach that is used in the model basin. The second method is capable of modeling wave breaking. Therefore, the parabolic beach in the model test basin can be modeled and has also been included. Energy dissipation therefore takes place according to physics which are more related to the situation in the model test basin. Three types of waves are generated in the model test basin and in the numerical wave tanks. All these waves are generated on basin scale. The following waves are considered: 1. A scaled 100-year North-Sea wave (Hs = 0.24 meters, Tp = 2.0 seconds) in deep water (5 meters). 2. A scaled operational wave (Hs = 0.086 meters, Tp = 1.69 seconds) at intermediate water depth (0.86 meters) generated by a flap-type wave generator. 3. A scaled operational wave (Hs = 0.046 meters, Tp = 1.2 seconds) in shallow water (0.35 meters) generated by a piston-type wave generator. The waves are generated by means of a flap or piston-type wave generator. The motions of the wave generator in the simulations (either rotational or translational) are identical to the motions in the model test basin. Furthermore, in the simulations with intermediate water depth, the non-flat contour of the basin bottom (ramp) is accurately modeled. A comparison is made between the measured and computed wave elevation at several locations in the basin. The comparison focuses on: 1. Reflection characteristics of the model test basin and the numerical wave tanks. 2. The accuracy in the prediction of steep waves. 3. Second order effects like set-down in intermediate and shallow water depth. Furthermore, a convergence study is presented to check the grid independence of the wave tank predictions.

The Effect of the Top Wall Temperature on the Laminar Natural Convection in Rectangular Cavities With Different Aspect Ratios

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Wenjiang Wu ◽  
Chan Y. Ching
Keyword(s):  
Natural Convection ◽  
Aspect Ratio ◽  
Wall Temperature ◽  
Vertical Wall ◽  
Flow Region ◽  
Temperature Profiles ◽  
Aspect Ratios ◽  
Vertical Walls ◽  
C And N ◽  
Laminar Natural Convection

The effect of the top wall temperature on the laminar natural convection in air-filled rectangular cavities driven by a temperature difference across the vertical walls was investigated for three different aspect ratios of 0.5, 1.0, and 2.0. The temperature distributions along the heated vertical wall were measured, and the flow patterns in the cavities were visualized. The experiments were performed for a global Grashof number of approximately 1.8×108 and nondimensional top wall temperatures from 0.52 (insulated) to 1.42. As the top wall was heated, the flow separated from the top wall with an undulating flow region in the corner of the cavity, which resulted in a nonuniformity in the temperature profiles in this region. The location and extent of the undulation in the flow are primarily determined by the top wall temperature and nearly independent of the aspect ratio of the cavity. The local Nusselt number was correlated with the local Rayleigh number for all three cavities in the form of Nu=C⋅Ran, but the values of the constants C and n changed with the aspect ratio.

scholarly journals A new solution approach to the Serre equations

2020 ◽  
Author(s):  
T S Jang
Keyword(s):  
Solitary Wave ◽  
Vertical Wall ◽  
High Amplitude ◽  
Solution Procedure ◽  
Linear Wave ◽  
Linear Interaction ◽  
Solution Approach ◽  
Non Linear ◽  
Vertical Walls ◽  
Wave Phenomena

Abstract This paper concerns constructing a semi-analytic solution procedure for integrating the fully non-linear Serre equations (or 1D Green–Naghdi equations for constant water depth). The validity of the solution procedure is checked by investigating a moving solitary wave for which the analytical solution is known. The semi-analytic procedure constructed in this study is confirmed to be good at observing non-linear wave phenomena of the collision of a sufficiently high-amplitude solitary wave with a vertical wall. The simulated results are in a good agreement with data of other authors. Further, the procedure simulates the non-linear interaction of four solitary waves, which enables us to investigate the repeated reflection of a single solitary wave between two vertical walls.

Lattice Defects in Epitaxial Ba2Bi4Ti5O18 Thin Films Grown by Pulsed Laser Deposition Onto LaNiO3 Bottom Electrodes

2000 ◽  
Vol 623 ◽  
Author(s):  
N.D. Zakharov ◽  
A.R. James ◽  
A. Pignolet ◽  
S. Senz ◽  
D. Hesse
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Stacking Sequence ◽  
Rectangular Shape ◽  
Transmission Electron ◽  
Single Well ◽  
New Type

AbstractEpitaxial, ferroelectric Ba2Bi4Ti5O18 films grown on LaNiO3/CeO2/ZrO2:Y2O3 epitaxial layers on Si(100) are investigated by cross-section high-resolution transmission electron microscopy (HRTEM). The films are perfectly oriented and consist of well-developed grains of rectangular shape. The grain boundaries are strained and contain many defects, especially a new type of defect, which can be described as a staircase formed by repeated lattice shifts of Δ ∼ c/12 ∼ 4.2 Å in the [001] direction. This repeated shift results in seemingly bent ribbons of stacked Bi2O2 planes, involving, however, individual Bi2O2 planes which remain strongly parallel to the (001) plane. These defects contain an excess of bismuth. Other defects found in the grain interior include mistakes in the stacking sequence originating from the presence of single, well-oriented, non-stoichionietric layers intergrown with the stoichiometric Ba2Bi4Ti5O18 film matrix.

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