Velocity, Pressure, and Dam-Break Similarity of Green Water Flow on a 3D Structure

2011 ◽  
Author(s):  
Kuang-An Chang ◽  
Kusalika Ariyarathne ◽  
Richard Mercier
Keyword(s):  
Vertical Wall ◽  
Three Dimensional ◽  
Dam Break ◽  
Green Water ◽  
Breaking Wave ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Wave Condition ◽  
Wall Impingement ◽  
The Impact

Flow dynamics of green water due to plunging breaking waves interacting with a simplified, three-dimensional model structure was investigated in laboratory. Two breaking wave conditions were tested: one with waves impinging and breaking on the vertical wall of the model at the still water level (referred as wall impingement) and the other with waves impinging and breaking on the horizontal deck surface (referred as deck impingement). The bubble image velocimetry (BIV) technique was used to measure the flow velocity. Measurements were taken on a vertical plane located at the center of the deck surface and a horizontal plane located slightly above the deck surface. The applicability of dam-break theory on green water velocity prediction for the three-dimensional model was also investigated. Furthermore, pressure measurements were performed at several locations above the horizontal deck surface for the wall impingement wave condition. Predictions of maximum impact pressure based on the measured pressure and flow velocities were investigated using the impact coefficient approach that links pressure with kinetic energy.

Relation Between Flow Velocity and Impact Pressure in a Green Water Flow

2013 ◽  
Author(s):  
Kusalika Ariyarathne ◽  
Kuang-An Chang ◽  
Richard Mercier
Keyword(s):  
Kinetic Energy ◽  
Void Fraction ◽  
Pressure Rise ◽  
Impact Pressure ◽  
Breaking Wave ◽  
Wave Condition ◽  
Wall Impingement ◽  
Impact Coefficient ◽  
The Impact ◽  
Mean Kinetic Energy

Impact pressure due to plunging breaking waves impinging on a simplified model structure was investigated in the laboratory based on two breaking wave conditions: the wall impingement wave condition and the deck impingement wave condition. Pressure, void fraction, and velocities were measured at various locations on the deck surface. Impact pressure was correlated with the mean kinetic energy calculated based on the measured mean velocities and void fraction to obtain the impact coefficient. For the wall impingement wave condition, the relationship between impact pressure and mean kinetic energy is linear with the impact coefficient close to unity. For the deck impingement wave condition, the above relationship does not show good correlation, whereas the impact coefficient was found to be a function of the rate of pressure rise.

scholarly journals Forecasting of Surface Currents via Correcting Wind Stress with Assimilation of High-Frequency Radar Data in a Three-Dimensional Model

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Lei Ren ◽  
Stephen Nash ◽  
Michael Hartnett
Keyword(s):  
Data Assimilation ◽  
High Frequency ◽  
Three Dimensional ◽  
Hf Radar ◽  
Surface Velocity ◽  
Shear Stresses ◽  
Surface Currents ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
The Impact

This paper details work in assessing the capability of a hydrodynamic model to forecast surface currents and in applying data assimilation techniques to improve model forecasts. A three-dimensional model Environment Fluid Dynamics Code (EFDC) was forced with tidal boundary data and onshore wind data, and so forth. Surface current data from a high-frequency (HF) radar system in Galway Bay were used for model intercomparisons and as a source for data assimilation. The impact of bottom roughness was also investigated. Having developed a “good” water circulation model the authors sought to improve its forecasting ability through correcting wind shear stress boundary conditions. The differences in surface velocity components between HF radar measurements and model output were calculated and used to correct surface shear stresses. Moreover, data assimilation cycle lengths were examined to extend the improvements of surface current’s patterns during forecasting period, especially for north-south velocity component. The influence of data assimilation in model forecasting was assessed using a Data Assimilation Skill Score (DASS). Positive magnitude of DASS indicated that both velocity components were considerably improved during forecasting period. Additionally, the improvements of RMSE for vector direction over domain were significant compared with the “free run.”

Simulating the Behaviour and Fate of an Oil Spill Using a Coupled Three-Dimensional Hydrodynamic Model

2014 ◽  
Vol 2014 (1) ◽  
pp. 901-918
Author(s):  
James A. Stronach ◽  
Aurelien Hospital
Keyword(s):  
Oil Spill ◽  
Hydrodynamic Model ◽  
Three Dimensional ◽  
Local Network ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Near Surface ◽  
Water Properties ◽  
Response Planning ◽  
The Impact

ABSTRACT Oil behavior and fate have been simulated extensively by several spill models. These simulations can be greatly enhanced by the use of a coupled three-dimensional model of currents and water properties to determine oil transport and weathering, both on the water surface and in the water column. Several physical and chemical processes such as vertical dispersion in response to wave action, resurfacing when waves die down, sinking through loss of volatiles and dissolution are essential in assessing the impact of an oil spill on the environment. Dissolution is especially important, considering the known toxicity of several of the constituents of liquid hydrocarbons. For this study, a three-dimensional hydrodynamic model of coastal British Columbia was coupled to an oil trajectory and weathering model in order to simulate the complete fate and behaviour of surface, shoreline-retained, dissolved, sunken and dispersed oil. Utilization of a three-dimensional model is the key to adequately modelling the transport of a spill in an estuarine region such as in the Strait of Georgia, B.C., where the distribution of currents and water properties is strongly affected by estuarine processes: the Fraser River enters at the surface and oceanic waters from the Pacific enter as a deep inflow. Three-dimensional currents and water properties were provided by the hydrodynamic model, H3D, a semi-implicit model using a staggered Arakawa grid and variable number of layers in the vertical direction to resolve near-surface processes. Waves were simulated using the wave model SWAN. Winds were obtained from the local network of coastal light stations and wind buoys. Stochastic modelling was conducted first, using only surface currents, to determine probabilistic maps of the oil trajectory on water and statistical results were extracted, such as the amount of shoreline oiled and the amount of oil evaporated, both for the ensemble of simulations constituting the stochastic simulation, as well as for any particular individual simulation. Deterministic scenarios were then selected and the fate of the oil, such as the dissolved and sunken fractions, was tracked over a 14 day period on the three-dimensional grid. This method has been used for environmental impact assessment and spill response planning.

Research of the Installation Angle of New Rotor Impact Plate Based on EDEM

2011 ◽  
Vol 80-81 ◽  
pp. 1133-1137
Author(s):  
De Rong Duan ◽  
Fang Zhao ◽  
Song Wang ◽  
Xian Xin Chen
Keyword(s):  
Dynamic Simulation ◽  
Impact Force ◽  
Three Dimensional ◽  
Substantial Effect ◽  
Maximum Speed ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Installation Angle ◽  
Impact Plate ◽  
The Impact

The three-dimensional model of new rotor was imported into EDEM for dynamic simulation, the maximum speed and force were analysied in the EDEM,indicating that the material along the deterministic trajectory collide with the impact plate for second acceleration after the first acceleration in new rotor, the velocity after second acceleration was 2.3 times than the first acceleration.The impact force and angle did not substantial effect on the second acceleration by comprehensive comparing,the 69m/s speed and less impact force were generated in the new rotor with 2° impact plate installation angle.

Laminar Natural Convection in a Discretely Heated Cavity: I—Assessment of Three-Dimensional Effects

1995 ◽  
Vol 117 (4) ◽  
pp. 902-909 ◽  
Author(s):  
T. J. Heindel ◽  
S. Ramadhyani ◽  
F. P. Incropera
Keyword(s):  
Natural Convection ◽  
Vertical Wall ◽  
Three Dimensional ◽  
Companion Paper ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Nusselt Numbers ◽  
Aspect Ratios ◽  
Laminar Natural Convection

Two and three-dimensional calculations have been performed for laminar natural convection induced by a 3 × 3 array of discrete heat sources flush-mounted to one vertical wall of a rectangular cavity whose opposite wall was isothermally cooled. Edge effects predicted by the three-dimensional model yielded local and average Nusselt numbers that exceeded those obtained from the two-dimensional model, as well as average surface temperatures that were smaller than the two-dimensional predictions. For heater aspect ratios Ahtr ≲ 3, average Nusselt numbers increased with decreasing Ahtr. However, for Ahtr ≳ 3, the two and three-dimensional predictions were within 5 percent of each other and results were approximately independent of Ahtr. In a companion paper (Heindel et al., 1995a), predictions are compared with experimental results and heat transfer correlations are developed.

The Dynamic Simulation Study of WN Gear Pair after Coupling Tribology

2014 ◽  
Vol 577 ◽  
pp. 214-217
Author(s):  
Yu Guang Li ◽  
Guo Qing Zhang
Keyword(s):  
Dynamic Simulation ◽  
Three Dimensional ◽  
Dynamic Contact ◽  
Axial Vibration ◽  
Dimensional Model ◽  
Analysis Model ◽  
Ansys Software ◽  
Three Dimensional Model ◽  
Dimensional Simulation ◽  
The Impact

Based on WN gear characteristics and considering system error, a multi-degree-freedom (Tangential-Radial-Axial) dynamics analysis model after coupling friction was established. In this article, we established the three-dimensional solid model by using PROE and then imported WN gear’ three-dimensional model into Ansys software through the data interface of Ansys software and PROE software and conducted a three-dimensional simulation anasys of the impact of dynamic contact. By applying load, the stress analysis of WN gear was conducted and the WN gear’s the effective stress clouds was gotten. Meanwhile, basing on ANSYS / LS-DYNA, it established the rigid-flexible body of gear dynamic contact model and analyzed the dynamic simulation anasys of WN gear. The results demonstrated that the tangential and axial vibration of double arc gear was significantly greater than the radial vibration.

Impact Pressure, Void Fraction, and Green Water Velocity due to Plunging Breaking Wave Impingement on a 2D Tension-Leg Structure

2016 ◽  
Author(s):  
Wei-Liang Chuang ◽  
Kuang-An Chang ◽  
Richard Mercier
Keyword(s):  
Void Fraction ◽  
Bubbly Flow ◽  
Vertical Wall ◽  
Pressure Sensors ◽  
Density Variation ◽  
Impact Pressure ◽  
Green Water ◽  
Breaking Wave ◽  
Peak Pressures ◽  
The Impact

Violent impacts due to plunging waves impinging on a 2D tension-leg model structure were experimentally investigated in a laboratory. In the experiment, velocities, pressures, and void fraction were simultaneously measured and the relationship among them was examined. The nonintrusive bubble image velocimetry technique was employed to quantify the instantaneous bubbly flow velocities and structure motion. Pressures on the structure vertical wall above the still water level were measured by four differential pressure sensors. Additionally, four fiber optic reflectometer probes were used to measure the void fraction coincidently with the pressure sensors. With repeated simultaneous, coincident velocity, pressure and void fraction measurements, temporal evolution of the ensemble-averaged velocities, pressures, and void fraction were demonstrated and correlated. Relationship between the peak pressures and their rise time was examined and summarized in dimensionless form. Impact coefficients that relate the impact pressure with flow kinetic energy were obtained from the ensemble-averaged measurements. Finally, the impact coefficients with and without the consideration of the fluid density variation due to bubbles were examined and compared.

A Three-Dimensional Model of Droplet Impinging, Solidification and Suspension on the Substrate

2011 ◽  
Vol 346 ◽  
pp. 222-227
Author(s):  
Sheng Zhu ◽  
Feng Liang Yin ◽  
Jian Liu ◽  
Yuan Yuan Liang
Keyword(s):  
Surface Tension ◽  
Manufacturing Process ◽  
Three Dimensional ◽  
Metal Droplet ◽  
The Body ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
High Impact Velocity ◽  
The Impact ◽  
First Time

A three-dimensional model was built to study a molten metal droplet impact on an edge of the substrate in droplet deposition manufacturing process for the first time. The whole calculation domain, including the substrate, was described using same fluid conservation equations, which is to say that the remolding and solidification of substrate was considered also. Droplet free surface was tracked by volume-of-fluid (VOF) algorithm. The effect of surface tension on the droplet was taken into consideration by means of considering surface tension to be a component of the body force. The simulated results show that the droplet in liquid phase can keep suspending on the substrate at a role of surface tension. A too high impact velocity would make parts of droplet splash away the substrate which is not allowed in manufacturing process. The offset between edge of droplet and side edge of substrate influences dramatically the impact of the droplet.

Green water impact pressure on a three-dimensional model structure

2012 ◽  
Vol 53 (6) ◽  
pp. 1879-1894 ◽  
Author(s):  
Kusalika Ariyarathne ◽  
Kuang-An Chang ◽  
Richard Mercier
Keyword(s):  
Three Dimensional ◽  
Impact Pressure ◽  
Green Water ◽  
Model Structure ◽  
Water Impact ◽  
Dimensional Model ◽  
Three Dimensional Model

Three-Dimensional Wave Basin Model Test for General-Purpose Wharf in Jinghai District of Jieyang Harbor

2013 ◽  
Vol 353-356 ◽  
pp. 2724-2731
Author(s):  
Shi Chang Yan ◽  
Shang Fei Lin ◽  
Guo Ping Chen
Keyword(s):  
Wave Height ◽  
Model Test ◽  
Three Dimensional ◽  
General Purpose ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Wave Condition ◽  
Navigation Channel ◽  
Wave Basin ◽  
Dimensional Wave

Three-dimensional model test in wave basin is launched to obtain the designed wave elements for the harbor, and the distribution of wave height in port and the overtopping on wharf surface in the project of all-purpose wharf in Jinghai district of Jieyang Harbor. The length scale of the physical model is 1:100. To compare the wave height and overtopping in different layout schemes under the same experimental condition, the optimal scheme is scheme 2 in which the wharf structure of 1 # berth is arranged in the east and the breakwater is extended about 580 meters. Meanwhile, the effect of navigation channel on wave transmission and wave condition in harbor is briefly discussed.

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