Tests and Applications of a Numerical Model for Nonlinear Wave Propagation on Non-Uniform Current

2010 ◽  
Author(s):  
Hong-sheng Zhang ◽  
Wei-yuan Wang ◽  
Wen-jing Feng ◽  
Jian-min Yang ◽  
Shi-qiang Lu
Keyword(s):  
Wave Propagation ◽  
Numerical Model ◽  
Laboratory Data ◽  
Wave Model ◽  
Nonlinear Wave Propagation ◽  
Wave Flume ◽  
Breaking Mechanism ◽  
Uniform Current ◽  
Fourth Order Model ◽  
Boussinesq Models

A Boussinesq-type wave model is used to investigate the interaction of waves with a non-uniform current field. The numerical model is first tested for wave propagation in a wave flume of uniform depth without current. It is then tested in a wave flume for a submerged bar. The validated numerical model is of higher accuracy than the fully-nonlinear fourth-order model, which is one of the best forms among the existing conventional Boussinesq models that do not incorporate breaking mechanism in one dimension. Comparison of model results with laboratory data shows the model is capable of representing wave-current interactions. The effect of current on wave is studied for different incident wave conditions, and the wave blocking is simulated successfully.

scholarly journals COUPLING OF A BOUSSINESQ WAVE MODEL WITH A MOORED SHIP BEHAVIOR MODEL

2012 ◽  
Vol 1 (33) ◽  
pp. 69 ◽  
Author(s):  
Liliana Vieira Pinheiro ◽  
Conceição Fortes ◽  
João Santos ◽  
José Leonel Fernandes
Keyword(s):  
Time Series ◽  
Wave Propagation ◽  
Numerical Model ◽  
Wave Model ◽  
Wave Forces ◽  
Behavior Model ◽  
Nonlinear Wave Propagation ◽  
Practical Applications ◽  
Ship Behavior

A set of procedures to evaluate the time series of the diffraction forces on a moored ship inside a harbor basin is presented. Nonlinear wave propagation is obtained using a Boussinesq finite element numerical model, BOUSS-WMH. Determination of hydrodynamic forces acting on the ship is achieved using a modified version of the WAMIT model. Finally, time series of the wave forces on the ship and of the inherent motions of the moored ship are obtained using BAS numerical model. The main focuses of this work are: the coupling of these three models and the modification of the method used in WAMIT to determine diffraction forces. Some simple and practical applications of this procedure are presented as well.

Numerical Investigation of the Influences of Fishing Net on Waves

2015 ◽  
Author(s):  
Yunpeng Zhao ◽  
Chunwei Bi ◽  
Guohai Dong ◽  
Changping Chen ◽  
Yucheng Li
Keyword(s):  
Porous Media ◽  
Wave Propagation ◽  
Numerical Model ◽  
Least Squares Method ◽  
Numerical Results ◽  
Numerical Wave Flume ◽  
Wave Flume ◽  
Physical Model Tests ◽  
Porous Media Model ◽  
Volume Method

A two-dimensional numerical wave flume is established based on the finite-volume method. The movement border method is adopted as a wave generator at one end of the flume. The volume of fluid (VOF) method is used to track the wave surface. In the numerical simulation, the plane net is simplified as porous-media model. The coefficients of the porous media are determined by the least squares method. In this way, the porous-media model will has the same pressure drop with the fishing net. To validate the numerical model, the numerical results are compared with the data obtained from corresponding physical model tests. It is found that the numerical results are in good agreement with the corresponding experimental data. Using the proposed numerical model, wave propagation through a plane net with different net solidities, different attack angles as well as two nets with different spacing distances are investigated. The impacts of the wave height and wavelength on the wave propagation through the plane net are also discussed.

scholarly journals Efficient Wave Modeling Using Non-Hydrostatic Pressure Distribution and Free Surface Tracking on Fixed Grids

2018 ◽  
Author(s):  
Hans Bihs ◽  
Arun Kamath ◽  
Ankit Aggarwal ◽  
Csaba Pakozdi
Keyword(s):  
Wave Propagation ◽  
Free Surface ◽  
Hydrostatic Pressure ◽  
Numerical Model ◽  
Wave Model ◽  
Current Paper ◽  
3D Simulation ◽  
Wave Forces ◽  
New Approach ◽  
2D Simulation

For the estimation of wave loads on offshore structures, relevant extreme wave events need to be identified. In order to achieve this, long term wave simulations of relatively large scales need to be performed. Computational Fluid Dynamics (CFD) based Numerical Wave Tanks (NWT) with an interface capturing two-phase flow approach typically require too large computational resources to achieve this efficiently. They are more suitable for the near-field hydrodynamics of steep and breaking wave impacts on the structures. In the current paper, a three-dimensional non-hydrostatic wave model is presented. While it also solves the Navier-Stokes equations, it employs an interface tracking method for the calculation of the free surface location. The algorithm for the simulation of the free surface is based on the continuity of the horizontal velocities along the vertical water column. With this approach, relatively fewer cells are needed in the vicinity of the air-water interface compared to CFD based NWTs. With coarser grids and larger time steps, the wave propagation can be accurately predicted. The numerical model solves the governing equations on an rectilinear grid, which allows for the employment of high-order finite differences. For time stepping, a fractional step method with implicit treatment of the diffusion terms is employed. The projection method is used for the calculation of the non-hydrostatic pressure. The resulting Poisson equation is solved with Hypres geometric multigrid preconditioned conjugated gradient algorithm. The numerical model is parallelized following the domain decomposition strategy and MPI communication between the individual processors. In the current paper, the capabilities of the new wave model are presented by comparing the wave propagation in the tank with the CFD approach in a 2D simulation. Further, a 3D simulation is carried out to determine the wave forces on a vertical cylinder. The calculated wave forces using the new approach is compared to that obtained using the CFD approach and experimental data. It is seen that the new approach provides a similar accuracy to that from the CFD approach while providing a large reduction in the time taken for the simulation. The gain is calculated to be about 4.5 for the 2D simulation and about 7.1 for the 3D simulation.

scholarly journals Hydraulic Transients in Viscoelastic Pipeline System with Sudden Cross-Section Changes

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4071
Author(s):  
Michał Kubrak ◽  
Agnieszka Malesińska ◽  
Apoloniusz Kodura ◽  
Kamil Urbanowicz ◽  
Michał Stosiak
Keyword(s):  
Numerical Model ◽  
Cross Section ◽  
Laboratory Data ◽  
Experimental Studies ◽  
Distribution Networks ◽  
Water Hammer ◽  
Fluid Distribution ◽  
Pipeline System ◽  
Hydraulic Transients ◽  
Single Pipe

It is well known that the water hammer phenomenon can lead to pipeline system failures. For this reason, there is an increased need for simulation of hydraulic transients. High-density polyethylene (HDPE) pipes are commonly used in various pressurised pipeline systems. Most studies have only focused on water hammer events in a single pipe. However, typical fluid distribution networks are composed of serially connected pipes with various inner diameters. The present paper aims to investigate the influence of sudden cross-section changes in an HDPE pipeline system on pressure oscillations during the water hammer phenomenon. Numerical and experimental studies have been conducted. In order to include the viscoelastic behaviour of the HDPE pipe wall, the generalised Kelvin–Voigt model was introduced into the continuity equation. Transient equations were numerically solved using the explicit MacCormack method. A numerical model that involves assigning two values of flow velocity to the connection node was used. The aim of the conducted experiments was to record pressure changes downstream of the pipeline system during valve-induced water hammer. In order to validate the numerical model, the simulation results were compared with experimental data. A satisfactory compliance between the results of the numerical calculations and laboratory data was obtained.

scholarly journals Analytical mathematical schemes: Circular rod grounded via transverse Poisson’s effect and extensive wave propagation on the surface of water

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 545-554
Author(s):  
Asghar Ali ◽  
Aly R. Seadawy ◽  
Dumitru Baleanu
Keyword(s):  
Wave Propagation ◽  
Partial Differential Equations ◽  
Differential Equations ◽  
Longitudinal Wave ◽  
Symbolic Computation ◽  
Boussinesq Equation ◽  
Nonlinear Partial Differential Equations ◽  
Wave Model ◽  
Simple Equation ◽  
Partial Differential

AbstractThis article scrutinizes the efficacy of analytical mathematical schemes, improved simple equation and exp(-\text{Ψ}(\xi ))-expansion techniques for solving the well-known nonlinear partial differential equations. A longitudinal wave model is used for the description of the dispersion in the circular rod grounded via transverse Poisson’s effect; similarly, the Boussinesq equation is used for extensive wave propagation on the surface of water. Many other such types of equations are also solved with these techniques. Hence, our methods appear easier and faster via symbolic computation.

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