scholarly journals A NUMERICAL STUDY ON SURFACE WAVE EVOLUTION OVER VISCOELASTIC MUD

2018 ◽  
pp. 64
Author(s):  
Elham Sharifineyestani ◽  
Navid Tahvildari
Keyword(s):  
Surface Wave ◽  
Numerical Study ◽  
Current Model ◽  
Resonance Effect ◽  
Wave Model ◽  
Form Solution ◽  
Random Wave ◽  
Complex Frequency ◽  
Wave Evolution ◽  
Domain Phase

A numerical modeling approach is applied to investigate the combined effect of wave-current-mud on the evolution of nonlinear waves. A frequency-domain phase-resolving wave-current model that solves nonlinear wave-wave interactions is used to solve wave evolution. A comparison between the results of numerical wave model and the laboratory experiments confirms the accuracy of the numerical model. The model is then applied to consider the effect of mud properties on nonlinear surface wave evolution. It is shown that resonance effect in viscoelastic mud creates a complex frequency-dependent dissipation pattern. In fact, due to the resonance effect, higher surface wave frequencies can experience higher damping rates over viscoelastic mud compared to viscous mud in both permanent form solution and random wave scenarios. Thus, neglecting mud elasticity can result in inaccuracies in estimating total wave energy and wave shape.

A numerical study on nonlinear surface wave evolution over viscoelastic mud

2019 ◽  
Vol 154 ◽  
pp. 103557
Author(s):  
Navid Tahvildari ◽  
Elham Sharifineyestani
Keyword(s):  
Surface Wave ◽  
Numerical Study ◽  
Wave Evolution ◽  
Nonlinear Surface

A Numerical Study on the Evolution of Random Seas With the Occurrence of Rogue Waves

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
Zhuowei Zhou ◽  
Ningchuan Zhang ◽  
Guoxing Huang
Keyword(s):  
Numerical Study ◽  
Wave Model ◽  
Rogue Waves ◽  
Experimental Investigations ◽  
Random Wave ◽  
Initial State ◽  
Incoming Wave ◽  
Spectral Parameters ◽  
Excess Kurtosis ◽  
Wave Trains

Abstract Numerous numerical and experimental investigations show that rogue waves present much larger probabilities of occurrence than predicted by the linear random wave model, i.e., Gaussian distributed waves. The deviation from normal statistical events excites a continuous concern about rogue wave research. In this study, rogue waves under long-crested and narrow-banded wave trains are checked using the high-order spectral (HOS)-NST model. The JONSWAP wave spectra with random phases are selected as the initial state of the incoming wave trains. Different values of spectral parameters are chosen to reproduce different random sea states with different Benjamin–Feir index (BFI). Numerical results are compared with the classical experimental study and show good agreements. Statistical properties of rogue waves are recounted again within the analysis of exceedance distribution function (EDF) of wave heights and wave crests. Spectral changes are examined, and the monotonic increases with BFI are stressed. However, no bifurcations are observed for BFI near 1. For large BFI, quasi-resonance interactions dominate the wave nonlinearities, and the resulted dynamic excess kurtosis involves initially monotonic enhancement along with space, peaking at around 20–30 wavelengths, but stays at stably high-level values. The quasi-steady-state of dynamic excess kurtosis after full interaction of wave nonlinearities in time and space demonstrates a continuous emergence of rogue waves much more frequent than normality. The changes of excess kurtosis along x are complicated where BFI near 1 and the occurrence of rogue waves might be enhanced even for BFI slightly inferior to 1.

A Numerical Study on the Evolution of Random Seas With the Occurrence of Rogue Waves

2020 ◽  
Author(s):  
Zhuowei Zhou ◽  
Ningchuan Zhang ◽  
Guoxing Huang
Keyword(s):  
Numerical Study ◽  
Experimental Studies ◽  
Wave Model ◽  
Rogue Waves ◽  
Experimental Investigations ◽  
Random Wave ◽  
Initial State ◽  
Incoming Wave ◽  
Energetic State ◽  
Wave Research

Abstract Numerous numerical and experimental investigations show that rogue waves present a much larger probability of occurrence than expected from the linear random wave model, i.e., Gaussian distributed waves. The deviation from normal statistical events excites a continuous concern about rogue-wave research. In this study, rogue waves under random wave seas are addressed within the framework of the horizontal 1-D fully nonlinear Euler equations. The JONSWAP wave spectra with a different set of random phases are selected as the initial state of the recurrences of incoming wave trains. Different values of spectrum parameters (i.e., enhancement factor γ and significant wave height Hs) for JONSWAP spectra are chosen in order to reproduce different random sea states with different BFI values. The results of the numerical method using in this study are compared with classical experimental studies of rogue waves and show good agreements. Nonlinear wave interactions and the evolution of simulated waves are investigated in order to study the emergence of rogue waves. Statistics analysis is applied to the simulating results to find the deviations with normal distributions. Numerical results reveal that the initial unstable waves need some space to evolve, i.e., around 20 wavelengths, and will keep in an energetic state for the formation of rogue waves.

Surface and interfacial anti-plane waves in micropolar solids with surface energy

2020 ◽  
pp. 108128652096564
Author(s):  
Mriganka Shekhar Chaki ◽  
Victor A Eremeyev ◽  
Abhishek K Singh
Keyword(s):  
Surface Wave ◽  
Plane Wave ◽  
Numerical Study ◽  
Plane Waves ◽  
Angular Frequency ◽  
Elastic Half Space ◽  
Surface Strain ◽  
Theoretical Frameworks ◽  
Algebraic Form ◽  
New Type

In this work, the propagation behaviour of a surface wave in a micropolar elastic half-space with surface strain and kinetic energies localized at the surface and the propagation behaviour of an interfacial anti-plane wave between two micropolar elastic half-spaces with interfacial strain and kinetic energies localized at the interface have been studied. The Gurtin–Murdoch model has been adopted for surface and interfacial elasticity. Dispersion equations for both models have been obtained in algebraic form for two types of anti-plane wave, i.e. a Love-type wave and a new type of surface wave (due to micropolarity). The angular frequency and phase velocity of anti-plane waves have been analysed through a numerical study within cut-off frequencies. The obtained results may find suitable applications in thin film technology, non-destructive analysis or biomechanics, where the models discussed here may serve as theoretical frameworks for similar types of phenomena.

Morphological characterization of bicontinuous structures in polymer blends and microemulsions by the inverse-clipping method in the context of the clipped-random-wave model

2000 ◽  
Vol 61 (6) ◽  
pp. 6773-6780 ◽  
Author(s):  
Hiroshi Jinnai ◽  
Yukihiro Nishikawa ◽  
Sow-Hsin Chen ◽  
Satoshi Koizumi ◽  
Takeji Hashimoto
Keyword(s):  
Polymer Blends ◽  
Wave Model ◽  
Morphological Characterization ◽  
Random Wave

Numerical Study on Wave Attenuation of Tsunami-Like Wave by Emergent Rigid Vegetation

2021 ◽  
pp. 1-28
Author(s):  
K. Qu ◽  
G. Y. Lan ◽  
S. Kraatz ◽  
W. Y. Sun ◽  
B. Deng ◽  
...  
Keyword(s):  
Solitary Waves ◽  
Wave Energy ◽  
Wave Attenuation ◽  
Tsunami Wave ◽  
Numerical Study ◽  
Wave Model ◽  
Indian Ocean Tsunami ◽  
Vegetation Density ◽  
Rigid Vegetation ◽  
Total Wave

The extreme surges and waves generated in tsunamis can cause devastating damages to coastal infrastructures and threaten the intactness of coastal communities. After the 2004 Indian Ocean tsunami, extensive physical experiments and numerical simulations have been conducted to understand the wave attenuation of tsunami waves due to coastal forests. Nearly all prior works used solitary waves as the tsunami wave model, but the spatial-temporal scales of realistic tsunamis differ drastically from that of solitary waves in both wave period and wavelength. More recent work has questioned the applicability of solitary waves and been looking towards more realistic tsunami wave models. Therefore, aiming to achieve more realistic and accurate results, this study will use a parameterized tsunami-like wave based on wave observations during the 2011 Japan tsunami to study the wave attenuation of a tsunami wave by emergent rigid vegetation. This study uses a high-resolution numerical wave tank based on the non-hydrostatic wave model (NHWAVE). This work examines effects of prominent factors, such as wave height, water depth, vegetation density and width, on the wave attenuation efficiency of emergent rigid vegetation. Results indicate that the vegetation patch can dissipate a considerable amount of the total wave energy of the tsunami-like wave. However, the tsunami-like wave has a higher total wave energy, but also a lower wave energy dissipation rate. Results show that using a solitary instead of a tsunami-like wave profile can overestimate the wave attenuation efficiency of the coastal forest.

scholarly journals Numerical Study for Experiment on Wave Pattern of Internal Wave and Surface Wave in Stratified Fluid

2019 ◽  
Vol 33 (3) ◽  
pp. 236-244
Author(s):  
Ju-Han Lee ◽  
Kwan-Woo Kim ◽  
Kwang-Jun Paik ◽  
Won-Cheol Koo ◽  
Yeong-Gyu Kim
Keyword(s):  
Surface Wave ◽  
Internal Wave ◽  
Numerical Study ◽  
Wave Pattern ◽  
Stratified Fluid

scholarly journals Coupled wave-equation and eddy-current model for modelling and measuring propagating stress-waves

2015 ◽  
Vol 64 (2) ◽  
pp. 215-226
Author(s):  
Tommi Peussa ◽  
Anouar Belahcen
Keyword(s):  
Flux Density ◽  
Eddy Current ◽  
Current Model ◽  
Wave Model ◽  
Magnetic Flux Density ◽  
The Finite Element Method ◽  
Coupled Models ◽  
Steel Bar ◽  
Measured Stress ◽  
Coupled Wave

AbstractThe coupling of the propagating stress wave with the eddy current model is presented. The applied stress produces magnetization in the sample that can be measured outside the sample by measuring the resulting magnetic flux density. The stress and flux density measurements are made on a mechanically excited steel bar. The problem is modelled with the finite element method for both the propagating wave and the eddy current. Three aspects are considered: eddy current model using magnetization from the measurements, coupled wave and eddy current models, and coupled different dimensions in the wave model. The measured stress can be reproduced from the measured flux density by modelling. The coupled models work both for stress and flux couplings as well as for the different dimensionality couplings.

Numerical and Experimental Analysis of Extreme Slamming Loads on FPSO Bows

2002 ◽  
Author(s):  
Ole A. Hermundstad ◽  
Carl T. Stansberg ◽  
O̸yvind Hellan
Keyword(s):  
Wave Model ◽  
Element Model ◽  
Practical Method ◽  
Second Order ◽  
Random Wave ◽  
Fe Model ◽  
Time Step ◽  
Scaled Model ◽  
Structural Responses ◽  
Relative Motions

A practical method for prediction of slamming loads and structural responses in the bow of an FPSO is presented. Incoming waves are simulated by a second-order random wave model, which describes the water elevation and kinematics. Vessel motions are calculated by linear analysis. The diffracted wave field is calculated taking into account linear 3D diffraction. Relative motions are then estimated by combining the linear vessel motions, second-order incoming waves and linear diffraction. The relative motions and velocities at the bow are used as input to numerical slamming calculations. The bow is divided into 2D sections and a boundary value problem is solved for each section applying the generalized Wagner-method of Zhao & Faltinsen (1993) and Zhao et al (1996). The 2D slamming calculations account for the local pile-up of water on each side of the section during impact. Structural responses are calculated from a finite-element model of the bow using the exact pressure distribution from the slamming calculations. This is achieved by automatic mapping of pressures onto the outer surface of the FE-model and performing a quasi-static structural analysis for each time-step. The methods are implemented into a package of computer tools, allowing the user to perform the various steps in the process with little manual editing of data. The system runs easily on a standard PC. Measurements on a 1:55 scaled model of an FPSO are used for validation of the bow slamming calculations. The model was equipped with five 3.85m × 1.65m (full-scale) panels in the upper part of the bow for slamming force measurements. The tests were run in storm conditions with steep waves. The calculated slamming force on a panel located at the foremost tip of the bulwark, 12.8 meters above the mean waterline, is compared with measured results for selected extreme slamming events. Considering the complexity of this problem and the relative simplicity of the approach, the agreement is very good.

Wave Setup in Inlets: Some Practical Considerations

2007 ◽  
Author(s):  
Dale Kerper ◽  
Christian M. Appendini ◽  
Henrik Kofoed-Hansen ◽  
Ida Bro̸ker
Keyword(s):  
Numerical Models ◽  
Current Model ◽  
Wave Model ◽  
Total Water ◽  
Wave Runup ◽  
Modeling Tools ◽  
Mean Sea Level ◽  
Wave Setup ◽  
Astronomical Tide ◽  
Total Water Level

For the determination maximum flood elevations, a number of components contributing to the total water level need to be considered. For instance, astronomical tide, storm surge, relative changes in mean sea level, wave setup, wave runup and wave splash. In this study, numerical models were used to evaluate under which conditions wave setup penetrates into an idealized inlet. A number of idealized inlet/lagoon configurations were tested. A coupled wave-current model was used to assess the static component of the wave setup. A Boussinesq wave model was used to assess the influence of the dynamic oscillating component of the wave setup. This study demonstrates how numerical modeling tools can be effectively used to assess how wave setup develops depending on a specific inlet configuration.

Sign in / Sign up

Export Citation Format

Share Document