scholarly journals Generation of Water Waves Using Momentum Source Wave-Maker Applied to a RANS Solver

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Xing Feng ◽  
Wanqing Wu
Keyword(s):  
Water Waves ◽  
Control Volume ◽  
Momentum Equation ◽  
Equation Model ◽  
The Body ◽  
Numerical Wave Tank ◽  
Wave Tank ◽  
Wave Maker ◽  
Numerical Wave ◽  
Source Wave

Nowadays, as the development of Computational Fluid Dynamics (CFD) and the numerical wave tank (NWT) has advanced, numerical analysis has become increasingly useful and powerful for the ship designing and ship hydrodynamics. In this study, a momentum source wave-maker and an analytical relaxation wave absorber were embedded into 2D RANS equation model with RSM turbulence closure scheme to establish the NWT for ship designing and hydrodynamics. The VOF (volume-of-fluid) method was applied to accurately capture the water free surface. The body force-weighted scheme is chosen for pressure interpolation and the second order upwind scheme for discretization of the momentum equation. In order to calculate convection and diffusion fluxes through the control volume faces, PISO algorithm is adopted for pressure-velocity coupling. The momentum source function for wave generation and the analytical relaxation function for wave absorption were deduced for constructing the NWT (numerical wave tank). The proposed NWT was then validated by the laboratory measurements of Umeyama and the analytical solution, indicating that the constructed NWT is effective and accurate.

Development of 3-D Numerical Wave Tank and Applications on Comb-Type Breakwater

2010 ◽  
Author(s):  
Zhuo Fang ◽  
Liang Cheng ◽  
Ningchuan Zhang
Keyword(s):  
Offshore Structures ◽  
Wave Generation ◽  
Irregular Waves ◽  
Secondary Wave ◽  
Wave Forces ◽  
Numerical Wave Tank ◽  
Wave Reflections ◽  
Wave Tank ◽  
Numerical Wave ◽  
Source Wave

In this study, a 3-D numerical wave tank is developed, based on a commercial computational fluid dynamics (CFD) package (FLUENT) to predict wave forces on coastal and offshore structures. A source wave-generation method is introduced to FLUENT through user-defined functions to generate incident waves. Spongy layers are used on both upstream and downstream sides of the wave tank to reduce the effects of wave reflections and secondary wave reflections. Various wave trains, such as linear monochromatic waves, second order Stokes waves and irregular waves were generated by using different source functions. It is demonstrated through numerical examples that the source wave-generation method can accurately generate not only small amplitude waves but also nonlinear waves. The present numerical wave tank is validated against standing waves in front of a vertical breakwater. Interactions between waves and a comb-type breakwater are simulated using the present model. The numerical results are compared with physical experimental results. It is found that the present numerical wave tank simulated the wave and breakwater interactions well.

scholarly journals Generating Water Waves on Steady Currents Using Mass Source Wave Maker Coupled with Analytical Relaxation Wave Absorber

2021 ◽  
Vol 2021 ◽  
pp. 1-26
Author(s):  
Xing Feng ◽  
Jia Liu ◽  
Ruina Ma
Keyword(s):  
Water Waves ◽  
Current Flow ◽  
Two Dimensional ◽  
Mass Source ◽  
Current Structure ◽  
Structure Interaction ◽  
Uniform Current ◽  
Wave Maker ◽  
Numerical Wave ◽  
Source Wave

In order to numerically simulate the wave-current interaction problems frequently encountered by aquaculture structures, a two-dimensional numerical wave-current tank model was established here based on a mass source wave maker coupled with an analytical relaxation wave absorber. The wave-maker model and the wave-absorber model were embedded into a two-dimensional RANS solver, which was closed with RSM turbulence scheme. The volume of fluid (VOF) method was adapted to accurately capture the free surface between water and air. To generate a steady uniform current flow, the uniform current flow velocity was calculated at the left-hand-side (LHS) and right-had-side (RHS) outflow boundaries, respectively. Once the steady uniform current flow was generated over the whole computational domain, the target water wave was marked within a specified region by embedding the mass source function based on wave theory into the mass conservation equation and then propagated on the generated uniform current flow. To verify the accuracy of the numerical wave-current tank established here, some of the obtained numerical results were then compared with the experimental results and the analytical solutions, and they agreed well with each other, indicating that the model developed here has great ability in simulating water waves on uniform currents over constant water depth. The established numerical wave-current tank was then used to study the optimal layout of the mass source region and the effects of water current velocity on water surface wave parameters during regular wave coupling with uniform water currents. Meanwhile, the established model was extended to generate steep wave and apply in deep water conditions. Finally, the proposed methods were applied to investigate the wave-current-structure interaction problems and the propagation of solitary waves traveling with coplanar/counter currents. Model-data comparisons show that the developed model here is potentially useful and efficient for investigating the inevitable wave-current-structure interaction problems in aquaculture technologies.

A Nonlinear Numerical Wave Tank and its Applications

2013 ◽  
Author(s):  
Hui Sun ◽  
Odd M. Faltinsen
Keyword(s):  
Free Surface ◽  
Horizontal Cylinder ◽  
The Body ◽  
Numerical Wave Tank ◽  
Wave Tank ◽  
Fully Nonlinear ◽  
Reflected Waves ◽  
Numerical Wave ◽  
Nonlinear Free Surface ◽  
Numerical Beach

A two-dimensional fully nonlinear numerical wave tank is developed by using a boundary element method (BEM). The water depth can be shallow or deep. The waves are generated by simulating a piston wave maker or by specifying the input velocity at the upstream boundary. Fully nonlinear free surface conditions are satisfied in the numerical simulations. In the downstream region, a numerical beach is employed to dissipate the wave energy to avoid waves reflecting from the vertical downstream boundary. When there is a body piercing the free surface, another numerical beach is applied upstream the body to damp out only the reflected waves from the body. Two different applications are presented in this paper. The first one is to compute the pressure and velocity at any point inside the wave field. The other application is to calculate the forces on a horizontal cylinder fixed on the free surface. This second application is related to the investigation of the hydrodynamic forces on the pontoon of a fish farm. Nonlinearities are significant since the wave amplitudes can be large relative to the wavelength and the dimension of the cylinder.

Numerical Wave Tank Analysis of Wave Run-Up on a Truncated Vertical Cylinder

2011 ◽  
Author(s):  
Jang Kim ◽  
Rajeev Jaiman ◽  
Steve Cosgrove ◽  
Jim O’Sullivan
Keyword(s):  
Wave Solution ◽  
Field Potential ◽  
The Body ◽  
Far Field ◽  
Computational Domain ◽  
Numerical Wave Tank ◽  
Wave Tank ◽  
Closure Condition ◽  
Potential Wave ◽  
Numerical Wave

A new far-field closure condition for a CFD-based numerical wave tank that uses a potential wave solution to overlay the outer computational domain of a CFD solution is described. A prescribed potential wave solution covers the region beyond a diameter more than 10 times of floater footprints. The diffracted waves from the body are absorbed by the ‘potential-attractor’ terms applied in the intermediate CFD domain where the CFD solution for Navier-Stokes equation is gradually blended into far-field potential solution. The proposed model provides an efficient numerical wave tank for the case when incoming wave length is much longer than floater. In this case, the required mesh and domain size for numerical accuracy is mainly affected by the floater geometry and local wave kinematics near the floater and less dependent on the length scale of the incoming waves. The new numerical wave tank is first tested for a diffraction of a truncated cylinder exposed to long regular waves. Comparison with theoretical and experimental results demonstrates accuracy and efficiency of the new method.

Validation of a piston type wave-maker using Numerical Wave Tank

2017 ◽  
Vol 131 ◽  
pp. 57-67 ◽  
Author(s):  
Deepak Divashkar Prasad ◽  
Mohammed Rafiuddin Ahmed ◽  
Young-Ho Lee ◽  
Rajnish N. Sharma
Keyword(s):  
Numerical Wave Tank ◽  
Wave Tank ◽  
Type Wave ◽  
Wave Maker ◽  
Numerical Wave

Nonlinear Diffraction of Waves by a Submerged Shelf in Shallow Water

1998 ◽  
Vol 120 (4) ◽  
pp. 212-220 ◽  
Author(s):  
R. C. Ertekin ◽  
J. M. Becker
Keyword(s):  
Shallow Water ◽  
Water Waves ◽  
Nonlinear Effects ◽  
Open Boundary ◽  
Numerical Wave Tank ◽  
Cnoidal Waves ◽  
Wave Tank ◽  
Numerical Wave ◽  
Level I ◽  
The Time Domain

The diffraction of water waves by submerged obstacles in shallow water generally requires the use of a nonlinear theory since both dispersive and nonlinear effects are important. In this work, wave diffraction is studied in a numerical wave tank using the Level I Green-Naghdi (GN) equations. Cnoidal waves are generated numerically by a wave maker situated at one end of a two-dimensional numerical wave tank. At the downwave end of the tank, an open-boundary condition is implemented to simulate a wave-absorbing beach, and thus to reduce reflections. The GN equations are solved in the time-domain by employing a finite-difference method. The numerical method is applied to diffraction of cnoidal waves by a submerged shelf, or a sand bar, of considerable height relative to water depth. The predicted results are compared with the available experimental data which indicate the importance of nonlinearity for the shallow-water conditions.

scholarly journals Numerical and Experimental Studies on a Three-Dimensional Numerical Wave Tank

IEEE Access ◽  
2018 ◽  
Vol 6 ◽  
pp. 6585-6593 ◽  
Author(s):  
Xiaojie Tian ◽  
Qingyang Wang ◽  
Guijie Liu ◽  
Wei Deng ◽  
Zhiming Gao
Keyword(s):  
Experimental Studies ◽  
Three Dimensional ◽  
Numerical Wave Tank ◽  
Wave Tank ◽  
Numerical Wave

Numerical Investigation of Focused Waves and Their Interaction With a Vertical Cylinder Using REEF3D

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Hans Bihs ◽  
Mayilvahanan Alagan Chella ◽  
Arun Kamath ◽  
Øivind Asgeir Arntsen
Keyword(s):  
Free Surface ◽  
Stokes Equations ◽  
Free Surface Flows ◽  
Surface Elevation ◽  
Numerical Wave Tank ◽  
Free Surface Elevation ◽  
Wave Tank ◽  
Numerical Wave ◽  
Focused Wave ◽  
The Impact

For the stability of offshore structures, such as offshore wind foundations, extreme wave conditions need to be taken into account. Waves from extreme events are critical from the design perspective. In a numerical wave tank, extreme waves can be modeled using focused waves. Here, linear waves are generated from a wave spectrum. The wave crests of the generated waves coincide at a preselected location and time. Focused wave generation is implemented in the numerical wave tank module of REEF3D, which has been extensively and successfully tested for various wave hydrodynamics and wave–structure interaction problems in particular and for free surface flows in general. The open-source computational fluid dynamics (CFD) code REEF3D solves the three-dimensional Navier–Stokes equations on a staggered Cartesian grid. Higher order numerical schemes are used for time and spatial discretization. For the interface capturing, the level set method is selected. In order to test the generated waves, the time series of the free surface elevation are compared with experimental benchmark cases. The numerically simulated free surface elevation shows good agreement with experimental data. In further computations, the impact of the focused waves on a vertical circular cylinder is investigated. A breaking focused wave is simulated and the associated kinematics is investigated. Free surface flow features during the interaction of nonbreaking focused waves with a cylinder and during the breaking process of a focused wave are also investigated along with the numerically captured free surface.

MOTION OF FLOATING CAISSON USING 3D NUMERICAL WAVE TANK

2021 ◽  
Vol 77 (2) ◽  
pp. I_775-I_780
Author(s):  
Atsushi TAKAGI ◽  
Masashi WATANABE ◽  
Taro ARIKAWA
Keyword(s):  
Numerical Wave Tank ◽  
Wave Tank ◽  
Numerical Wave
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