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.

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.

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 EFFECT OF BOUSSINESQ EQUATIONS ON WAVE SPECTRA PROPAGATION

1988 ◽  
Vol 1 (21) ◽  
pp. 24
Author(s):  
J.P. Sierra ◽  
A.S. Arcilla ◽  
J.J. Egozcue ◽  
J.L. Monso
Keyword(s):  
Time Series ◽  
Wave Propagation ◽  
Spectral Analysis ◽  
Numerical Model ◽  
Boussinesq Equations ◽  
Density Functions ◽  
Wave Spectra ◽  
Irregular Wave ◽  
Propagation Effects ◽  
Spectral Density Functions

A 2-D numerical model has been developed to simulate wave propagation prior to breaking. This non linear hydrodynamic model works in connection with various spectral analysis routines. This paper intends to study the propagation effects on the wave time-series and on the corresponding spectral density functions in order to gain insight on both the spectral description of waves and irregular wave propagation.

New determinations of tides on the north-western Ross Ice Shelf

2020 ◽  
pp. 1-14
Author(s):  
Richard D. Ray ◽  
Kristine M. Larson ◽  
Bruce J. Haines
Keyword(s):  
Time Series ◽  
Tide Gauge ◽  
High Rate ◽  
Ice Shelf ◽  
Ross Ice Shelf ◽  
The North ◽  
Global Positioning ◽  
North Western

Abstract New determinations of ocean tides are extracted from high-rate Global Positioning System (GPS) solutions at nine stations sitting on the Ross Ice Shelf. Five are multi-year time series. Three older time series are only 2–3 weeks long. These are not ideal, but they are still useful because they provide the only in situ tide observations in that sector of the ice shelf. The long tide-gauge observations from Scott Base and Cape Roberts are also reanalysed. They allow determination of some previously neglected tidal phenomena in this region, such as third-degree tides, and they provide context for analysis of the shorter datasets. The semidiurnal tides are small at all sites, yet M2 undergoes a clear seasonal cycle, which was first noted by Sir George Darwin while studying measurements from the Discovery expedition. Darwin saw a much larger modulation than we observe, and we consider possible explanations - instrumental or climatic - for this difference.

scholarly journals Apparent Young’s Modulus of the Adhesive in Numerical Modeling of Adhesive Joints

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 328
Author(s):  
Kamil Anasiewicz ◽  
Józef Kuczmaszewski
Keyword(s):  
Numerical Model ◽  
Young’S Modulus ◽  
Adhesive Joint ◽  
Young's Modulus ◽  
Precise Determination ◽  
Adhesive Joints ◽  
Experimental Conditions ◽  
Element Simulation ◽  
Joint Material

This article is an evaluation of the phenomena occurring in adhesive joints during curing and their consequences. Considering changes in the values of Young’s modulus distributed along the joint thickness, and potential changes in adhesive strength in the cured state, the use of a numerical model may make it possible to improve finite element simulation effects and bring their results closer to experimental data. The results of a tensile test of a double overlap adhesive joint sample, performed using an extensometer, are presented. This test allowed for the precise determination of the shear modulus G of the cured adhesive under experimental conditions. Then, on the basis of the research carried out so far, a numerical model was built, taking the differences observed in the properties of the joint material into account. The stress distribution in a three-zone adhesive joint was analyzed in comparison to the standard numerical model in which the adhesive in the joint was treated as isotropic. It is proposed that a joint model with three-zones, differing in the Young’s modulus values, is more accurate for mapping the experimental results.

scholarly journals Regional Downscaling of Copernicus ERA5 Wave Data for Coastal Engineering Activities and Operational Coastal Services

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 859
Author(s):  
Giorgio Bellotti ◽  
Leopoldo Franco ◽  
Claudia Cecioni
Keyword(s):  
Time Series ◽  
National Level ◽  
Wave Model ◽  
Wave Climate ◽  
Tyrrhenian Sea ◽  
Computational Domain ◽  
Multiple Wave ◽  
Space Resolution ◽  
Wave Data ◽  
Fundamental Information

Hindcasted wind and wave data, available on a coarse resolution global grid (Copernicus ERA5 dataset), are downscaled by means of the numerical model SWAN (simulating waves in the nearshore) to produce time series of wave conditions at a high resolution along the Italian coasts in the central Tyrrhenian Sea. In order to achieve the proper spatial resolution along the coast, the finite element version of the model is used. Wave data time series at the ERA5 grid are used to specify boundary conditions for the wave model at the offshore sides of the computational domain. The wind field is fed to the model to account for local wave generation. The modeled sea states are compared against the multiple wave records available in the area, in order to calibrate and validate the model. The model results are in quite good agreement with direct measurements, both in terms of wave climate and wave extremes. The results show that using the present modeling chain, it is possible to build a reliable nearshore wave parameters database with high space resolution. Such a database, once prepared for coastal areas, possibly at the national level, can be of high value for many engineering activities related to coastal area management, and can be useful to provide fundamental information for the development of operational coastal services.

Sign in / Sign up

Export Citation Format

Share Document