scholarly journals NUMERICAL INVESTIGATION OF PLUNGING BREAKERS OVER A POROUS ARTIFICIAL SURF REEF

2018 ◽  
pp. 70
Author(s):  
Bjarne Jensen ◽  
Karl-Søren Geertsen ◽  
Johan Rønby ◽  
Simon B. Mortensen
Keyword(s):  
Numerical Model ◽  
Numerical Investigation ◽  
Breaking Waves ◽  
General Analysis ◽  
Coastal Protection ◽  
Reef Structure ◽  
New Locations ◽  
Plunging Breaker

This paper presents the results of a numerical investigation of breaking waves over an artificial surf reef (ASR). In the surfing industry, it has become common to establish artificial surf reefs to enhance the surfability at popular surf locations, or to attract surfers to new locations. Besides enhancing the surfing quality, an ASR can also be seen as a submerged detached breakwater, which is a well known type of structure for coastal protection. The construction of an ASR can therefore have the additional purpose of acting as a measure for coastal protection. Hereby the ASR becomes a multi-purpose reef. In this paper, we focus on two aspects of an ASR in relation to the effect of the porous reef: 1) a general analysis of the hydrodynamics of a plunging breaker over a reef, and 2) evaluation of specific parameters for describing the surfability and safety of the plunging breaker. The novelty of the work presented lays in the detailed inclusion of the porous reef structure in a numerical model that is applied for designing and evaluating an ASR.

Experimental and Numerical Investigation Into the Effects of Initial Conditions on a Three Degree of Freedom Capsize Model

2006 ◽  
Vol 50 (01) ◽  
pp. 63-84
Author(s):  
Young-Woo Lee ◽  
Leigh McCue ◽  
Michael Obar ◽  
Armin Troesch
Keyword(s):  
Numerical Model ◽  
Numerical Investigation ◽  
Initial Conditions ◽  
Degree Of Freedom ◽  
Transient Effects ◽  
Ultimate State ◽  
Extreme Behavior ◽  
Three Degree Of Freedom ◽  
Physical Phenomena ◽  
Ship Capsizing

The dynamics and hydrodynamics of ship capsizing include strong nonlinearities, transient effects, and physical phenomena that have not been fully identified or studied. This paper presents a study of some of the various mechanisms associated with this extreme behavior. A quasi-nonlinear three degree of freedom numerical model is employed to examine the effects of initial conditions on the ultimate state of a box barge model. The numerical results are then used to provide structure and understanding to otherwise seemingly inconsistent and ambiguous experiments.

Numerical Simulation of Wave Interaction With a Pair of Fixed Large Tandem Cylinders Subjected to Regular, Non-Breaking Waves

2021 ◽  
Author(s):  
M. Mohseni ◽  
C. Guedes Soares
Keyword(s):  
Numerical Model ◽  
Wave Field ◽  
Circular Cross Section ◽  
Wave Interaction ◽  
Breaking Waves ◽  
Wave Loading ◽  
Two Phase ◽  
Wave Regime ◽  
Wave Amplification ◽  
Vof Model

Abstract The wave interaction with cylinders placed in proximity results in significant modification of the wave field, wave-induced processes, and wave loading. The evaluation of such a complex wave regime and accurate assessment of the wave loading requires an efficient and accurate numerical model. Concerning the wave scattering types identified by Swan et al. (2015) and lateral progressive edge waves, this paper presents the application of a two-phase Computational Fluid Dynamics (CFD) model to carry out a detailed investigation of nonlinear wave field surrounding a pair of columns placed in the tandem arrangement in the direction of wave propagation and corresponding harmonics. The numerical analysis is conducted using the Unsteady Reynolds-Averaged Navier-Stokes/VOF model based on the OpenFOAM framework combined with the olaFlow toolbox for wave generation/absorption. For the simulations, the truncated cylinders are assumed vertical and surface piercing with a circular cross-section subjected to regular, non-breaking fifth-order Stokes waves propagating with moderate steepness in deep water. Primarily, the numerical model is validated with experimental data provided by ITTC (OEC)[1] for a single cylinder. Future, the given simulations are conducted for different centre-to-centre distances between the tandem large cylinders. The results show the evolution of a strong wave diffraction pattern and consequently high wave amplification harmonics around cylinders are apparent.

scholarly journals Experimental and Numerical Investigation of Pre-Breaking and Breaking Vorticity within a Plunging Breaker

Water ◽  
2018 ◽  
Vol 10 (4) ◽  
pp. 387 ◽  
Author(s):  
Diana De Padova ◽  
Maurizio Brocchini ◽  
Federica Buriani ◽  
Sara Corvaro ◽  
Francesca De Serio ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Plunging Breaker

The Numerical Investigation of Cracking Areas under Nonuniform Settlements of the Construction

2014 ◽  
Vol 472 ◽  
pp. 141-145
Author(s):  
Maria L. Bartolomey ◽  
Igor N. Shardakov ◽  
Nikolai A. Trufanov
Keyword(s):  
Numerical Model ◽  
Numerical Investigation ◽  
Three Dimensional ◽  
Strained State ◽  
Dimensional Model ◽  
Three Dimensional Model

We investigate the tensely-strained state of three-dimensional construction at the measured settlements of the foundation. The numerical model of the construction is developed within the limits of the theory of the plates bending and rectilinear rods, it allows to reveal dangerous places in the strength members particularly in the interfloor plate. The three-dimensional model of the dangerous area is developed, which allows to define the level of damaging the plates material. Settlements levels leading to first cracks and full destruction of the investigated area of the construction are defined.

Numerical Investigation of the Minimum Roof Thickness of Mining Stope in Bailing Copper-Zinc Mine

2014 ◽  
Vol 670-671 ◽  
pp. 668-673
Author(s):  
Jiang Feng Ma ◽  
Xiu Li Zhang ◽  
Yu Yong Jiao ◽  
Hu Nan Tian
Keyword(s):  
Rock Mass ◽  
Numerical Model ◽  
Stress Distribution ◽  
Numerical Investigation ◽  
Damage Zone ◽  
Three Dimensional ◽  
Surface Displacement ◽  
Ore Body ◽  
Zinc Mine ◽  
Copper Zinc

A three-dimensional numerical model of the rock mass including ore body is established by FLAC3D software, and then the surface subsidence caused by backfilling under different roof thicknesses of mining stope (the vertical distance between upper mining limit and surface) are calculated and analyzed. By comparing the surface displacement, the stress distribution, and the damage zone under different conditions, the minimum roof thickness is determined.

A Hybrid Numerical Model to Address Fluid Elastic Structure Interaction

2016 ◽  
Author(s):  
Manoj Kumar Gangadharan ◽  
Sriram Venkatachalam
Keyword(s):  
Numerical Model ◽  
Fluid Structure Interaction ◽  
Breaking Waves ◽  
Elastic Structure ◽  
Navier Stokes ◽  
Breaking Wave ◽  
Ocean Engineering ◽  
Fluid Structure ◽  
Strongly Coupled ◽  
Structure Interaction

Hydroelasticity is an important problem in the field of ocean engineering. It can be noted from most of the works published as well as theories proposed earlier that this particular problem was addressed based on the time independent/ frequency domain approach. In this paper, we propose a novel numerical method to address the fluid-structure interaction problem in time domain simulations. The hybrid numerical model proposed earlier for hydro-elasticity (Sriram and Ma, 2012) as well as for breaking waves (Sriram et al 2014) has been extended to study the problem of breaking wave-elastic structure interaction. The method involves strong coupling of Fully Nonlinear Potential Flow Theory (FNPT) and Navier Stokes (NS) equation using a moving overlapping zone in space and Runge kutta 2nd order with a predictor corrector scheme in time. The fluid structure interaction is achieved by a near strongly coupled partitioned procedure. The simulation was performed using Finite Element method (FEM) in the FNPT domain, Particle based method (Improved Meshless Local Petrov Galerkin based on Rankine source, IMPLG_R) in the NS domain and FEM for the structural dynamics part. The advantage of using this approach is due to high computational efficiency. The method has been applied to study the interaction between breaking waves and elastic wall.

scholarly journals Numerical Investigation of Tool Parameters Influence on the Interlock Forming During Flat Clinching Process

2021 ◽  
Author(s):  
Zhiyong Wang ◽  
Shanling Han ◽  
Zhiyong Li ◽  
Yong Li
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Linear Relationship ◽  
Numerical Investigation ◽  
Vital Role ◽  
Blank Holder ◽  
Finite Element Software ◽  
Punch Radius ◽  
Deform 2D ◽  
The Relationship

Abstract Tool parameters play a vital role in the mechanical interlock formation during the flat clinching process, to understand the influence of tool parameters on the interlock formation, the finite element software DEFORM-2D was used to build the numerical model of the flat clinching process, and the numerical model was verified by the experiment. The influences of the punch radius, punch fillet radius, and blank holder radius on the interlock formation of the clinched joint were investigated using the numerical model. Then, the relationship between the punch radius and blank holder radius was studied. The results showed that the interlock gradually increases with the increase of the blank holder radius, after that, the interlock begins to decrease. To maximize the interlock, the punch radius and the blank holder radius should be increased simultaneously. It can be concluded that the blank holder radius and the punch radius should keep in a linear relationship when designing the geometric dimensions of the flat clinch tools, which can promote the application of flat clinching process in car body manufacturing.

scholarly journals Experimental and numerical investigation of thermal flow meter

2015 ◽  
Vol 36 (3) ◽  
pp. 149-160 ◽  
Author(s):  
Artur Cebula
Keyword(s):  
Temperature Distribution ◽  
Numerical Model ◽  
Surface Temperature ◽  
Numerical Investigation ◽  
Flow Rate ◽  
Experimental Investigations ◽  
Thermal Flow ◽  
Wall Surface ◽  
Flow Meter ◽  
Calculation Results

Abstract The paper presents analytical and numerical model calculation results of the temperature distribution along the thermal flow meter. Results show a very good conformity between numerical and analytical model. Apart from the calculation results the experimental investigations are presented. The author performed the test where a temperature of duct wall surface was measured. The relation between mass flow rate in terms of the duct surface temperature difference was developed.

scholarly journals Numerical Modeling of Failure Mechanisms in Articulated Concrete Block Mattress as a Sustainable Coastal Protection Structure

2021 ◽  
Vol 13 (22) ◽  
pp. 12794
Author(s):  
Ramin Safari Ghaleh ◽  
Omid Aminoroayaie Yamini ◽  
S. Hooman Mousavi ◽  
Mohammad Reza Kavianpour
Keyword(s):  
Numerical Modeling ◽  
Concrete Block ◽  
Breaking Waves ◽  
Physical Models ◽  
Coastal Protection ◽  
Similarity Parameter ◽  
Environmental Friendliness ◽  
Shoreline Protection ◽  
Concrete Blocks ◽  
Run Up

Shoreline protection remains a global priority. Typically, coastal areas are protected by armoring them with hard, non-native, and non-sustainable materials such as limestone. To increase the execution speed and environmental friendliness and reduce the weight of individual concrete blocks and reinforcements, concrete blocks can be designed and implemented as Articulated Concrete Block Mattress (ACB Mat). These structures act as an integral part and can be used as a revetment on the breakwater body or shoreline protection. Physical models are one of the key tools for estimating and investigating the phenomena in coastal structures. However, it does have limitations and obstacles; consequently, in this study, numerical modeling of waves on these structures has been utilized to simulate wave propagation on the breakwater, via Flow-3D software with VOF. Among the factors affecting the instability of ACB Mat are breaking waves as well as the shaking of the revetment and the displacement of the armor due to the uplift force resulting from the failure. The most important purpose of the present study is to investigate the ability of numerical Flow-3D model to simulate hydrodynamic parameters in coastal revetment. The run-up values of the waves on the concrete block armoring will multiply with increasing break parameter (0.5<ξm−1,0<3.3) due to the existence of plunging waves until it (Ru2%Hm0=1.6) reaches maximum. Hence, by increasing the breaker parameter and changing breaking waves (ξm−1,0>3.3) type to collapsing waves/surging waves, the trend of relative wave run-up changes on concrete block revetment increases gradually. By increasing the breaker index (surf similarity parameter) in the case of plunging waves (0.5<ξm−1,0<3.3), the low values on the relative wave run-down are greatly reduced. Additionally, in the transition region, the change of breaking waves from plunging waves to collapsing/surging (3.3<ξm−1,0<5.0), the relative run-down process occurs with less intensity.

scholarly journals KNSwing—On the Mooring Loads of a Ship-Like Wave Energy Converter

2019 ◽  
Vol 7 (2) ◽  
pp. 29
Author(s):  
Kim Nielsen ◽  
Jonas Thomsen
Keyword(s):  
Numerical Model ◽  
Wave Energy ◽  
Numerical Models ◽  
Breaking Waves ◽  
Wave Energy Converter ◽  
Experimental Results ◽  
Irregular Waves ◽  
Mooring System ◽  
Energy Converter ◽  
The Waves

The critical function of keeping a floating Wave Energy Converter in position is done by a mooring system. Several WECs have been lost due to failed moorings, indicating that extreme loads, reliability and durability are very important aspects. An understanding of the interaction between the WEC’s motion in large waves and the maximum mooring loads can be gained by investigating the system at model scale supported by numerical models. This paper describes the testing of a novel attenuator WEC design called KNSwing. It is shaped like a ship facing the waves with its bow, which results in low mooring loads and small motions in most wave conditions when the structure is longer than the waves. The concept is tested using an experimental model at scale 1:80 in regular and irregular waves, moored using rubber bands to simulate synthetic moorings. The experimental results are compared to numerical simulations done using the OrcaFlex software. The experimental results show that the WEC and the mooring system survives well, even under extreme and breaking waves. The numerical model coefficient concerning the nonlinear drag term for the surge motion is validated using decay tests. The numerical results compare well to the experiments and, thereby, the numerical model can be further used to optimize the mooring system.

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