SPOT APPLICATION TOOL FOR WAVE DRIVEN NEARSHORE HYDRODYNAMICS

2017 ◽  
pp. 19
Author(s):  
Hoda El Safty ◽  
Patrick Lynett
Keyword(s):  
Wave Propagation ◽  
Time Domain ◽  
Wave Breaking ◽  
Numerical Models ◽  
Circulation Model ◽  
Wave Model ◽  
Tidal Currents ◽  
Nearshore Processes ◽  
Spectral Models ◽  
Infragravity Wave

Nearshore hydrodynamics are driven by a wide spectrum of motions/scales that vary on the order of O (10) m to O (100) km. These scales have different effects on the dynamics of the nearshore areas, and capturing these effects is essential in accurately modeling the nearshore processes such as: mixing and transport of pollutants, wave steeping and/or wave damping, erosion and deposition of sediments, and infragravity wave propagation. For example, in tidal inlets, waves interact with tidal-currents and bathymetry. The presences of waves alter the kinematics and the dynamics of the tidal-currents such as increasing the bottom friction due to wave bottom boundary layer and changing the vertical profile of the horizontal velocity from the well-known log profile. The tidal-currents affect the wave kinematics and dynamics such as Doppler shift, wave refraction, and wave steeping in opposite currents, wave breaking and infragravity wave propagation. The time and length scales of the current are much larger than those of the waves, and modeling this interaction using a single numerical model is numerically expensive. One approach to overcome this issue is through using multi-scale numerical modeling by coupling two or more numerical models. In literature, spectral wave models have been widely coupled with circulation models to study wave-current interaction. These spectral models can provide accurate predictions for wave height but they don’t provide accurate information about nonlinear wave statistics, i.e. wave skewness and asymmetry, which is a key parameter in sediment transport models. On the other hand, the phase-resolving models are capable of providing this information. In the current study, the large-scale circulation model, Delft3D, is coupled with time-domain Boussinesq-type wave model. The use of time domain wave model in the numerical coupling will improve the prediction of various nearshore processes such as: wave breaking and thus infragravity wave release and propagation, combined vertical velocity structure under external forcings of tidal currents. Such an application will fulfill the community needs for a "spot application tool" where we simulate wave-driven processes in a large domain with fine-resolution.

scholarly journals 1-D Implementation of Maxwell’s Equations in MATLAB to Study the Effect of Absorption Using PML

2012 ◽  
pp. 256-260
Author(s):  
Vikas Rathi ◽  
K. Shrivastava ◽  
Hemant S Pokhariya
Keyword(s):  
Wave Propagation ◽  
Partial Differential Equations ◽  
Finite Difference ◽  
Differential Equations ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Numerical Models ◽  
Time Domain Method ◽  
Propagation Behavior ◽  
Difference Time

The Finite Difference Time Domain method (FDTD) uses centre-difference representations of the continuous partial differential equations to create iterative numerical models of wave propagation. First we study the propagation behavior of the wave in single dimension without PML and in second part we study the absorption using PML for the same wave using MATLAB environment.

scholarly journals The Conformal Finite-Difference Time-Domain Simulation of GPR Wave Propagation in Complex Geoelectric Structures

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Man Yang ◽  
Hongyuan Fang ◽  
Dazhong Chen ◽  
Xueming Du ◽  
Fuming Wang
Keyword(s):  
Wave Propagation ◽  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Numerical Models ◽  
Underground Structure ◽  
Rectangular Mesh ◽  
Runge Kutta ◽  
Mode Tm ◽  
Difference Time

The finite-difference time-domain (FDTD) method adopts the most popular numerical model simulating ground penetrating radar (GPR) wave propagation in an underground structure. However, a staircase approximation method is usually adopted to simulate the curved boundary of an irregular object in the FDTD and symplectic partitioned Runge-Kutta (SPRK) methods. The approximate processing of rectangular mesh parameters will result in calculation errors and virtual surface waves for irregular targets of an underground structure. In this paper, we examine transverse mode (TM) electromagnetic waves with numerical models of electromagnetic wave propagation in geoelectric structures with conformal finite-difference time-domain (CFDTD) method technology in which the effective dielectric parameters are used to accurately simulate the dielectric surface and to absorb waves at the edges of the grid. The third orders of the transmission boundary are used in this paper. Additionally, three complex geocentric models of inclined layered media, spherical media, and three-layered pavement model with structural damages are set up for simulation calculations, then we carry out the actual radar wave detection in a laboratory as the fourth numerical example. Comparison of simulated reflectance waveform of FDTD, symplectic partitioned Runge-Kutta (SPRK), and CFDTD methods shows that at least 50% of the virtual waves can be reduced by using the proposed algorithm. Wiggle diagrams of FDTD and CFDTD methods show that much of the virtual waves have been reduced, and the radar image is clearer than before. This provides a method for the detection of complex geoelectric and layered structures in actual engineering.

scholarly journals Tidal Modulation of Surface Gravity Waves in the Gulf of Maine

2018 ◽  
Vol 48 (10) ◽  
pp. 2305-2323 ◽  
Author(s):  
Pengcheng Wang ◽  
Jinyu Sheng
Keyword(s):  
Wave Propagation ◽  
Gravity Waves ◽  
Gulf Of Maine ◽  
Circulation Model ◽  
Tidal Currents ◽  
Propagation Direction ◽  
Surface Gravity ◽  
Wave Propagation Direction ◽  
Surface Gravity Waves ◽  
Energy Convergence

AbstractThis study examines the tidal modulation of surface gravity waves in the Gulf of Maine (GoM) by using in situ observations and numerical model results. Analysis of observational data demonstrates significant semidiurnal tidal modulations in the mean wave variables for swell-dominated waves in the region. The observed tidal modulation features significant spatial–temporal variabilities, with large magnitudes near the mouth of the GoM. Observations also demonstrate unusual timing of the maximum modulation of significant wave height Hs in the following tidal currents. The coupled wave–circulation model successfully reproduces the observed tidal modulation and the associated spatial–temporal variabilities. Model results demonstrate that the maximum Hs modulations are first generated during the maximum flood tide or ebb tide near the mouth of the GoM and then propagate onto the inner gulf. Around the mouth of the GoM, tidal currents have strong spatial gradients, resulting in great effects of current-induced convergence, refraction, and wavenumber shift. The tidal modulation in Hs generated by convergence (10%–14%) is less affected by the wave propagation direction than the modulation generated by the wavenumber shift (6%–10%) and refraction (4%–20%). The latter modulation varies significantly with changes in the wave propagation direction. In addition, current-enhanced dissipation becomes important during high winds, which reduces at least one-half of the Hs modulation during the study period. The observed unusual timing of the maximum Hs modulation in the following tidal currents can be mostly explained by the convergence and wavenumber shift associated with wave-energy convergence and energy transfer from currents to waves in spatially decelerating currents.

scholarly journals Evaluating the accuracy and uncertainty of atmospheric and wave model hindcasts during severe events using model ensembles

2021 ◽  
Author(s):  
Ali Abdolali ◽  
Andre van der Westhuysen ◽  
Zaizhong Ma ◽  
Avichal Mehra ◽  
Aron Roland ◽  
...  
Keyword(s):  
Extreme Event ◽  
Numerical Models ◽  
Model Performance ◽  
Ground Truth ◽  
Wave Model ◽  
Atmospheric Model ◽  
Stationary Source ◽  
Source Point ◽  
Spectral Wave Model ◽  
Model Ensembles

AbstractVarious uncertainties exist in a hindcast due to the inabilities of numerical models to resolve all the complicated atmosphere-sea interactions, and the lack of certain ground truth observations. Here, a comprehensive analysis of an atmospheric model performance in hindcast mode (Hurricane Weather and Research Forecasting model—HWRF) and its 40 ensembles during severe events is conducted, evaluating the model accuracy and uncertainty for hurricane track parameters, and wind speed collected along satellite altimeter tracks and at stationary source point observations. Subsequently, the downstream spectral wave model WAVEWATCH III is forced by two sets of wind field data, each includes 40 members. The first ones are randomly extracted from original HWRF simulations and the second ones are based on spread of best track parameters. The atmospheric model spread and wave model error along satellite altimeters tracks and at stationary source point observations are estimated. The study on Hurricane Irma reveals that wind and wave observations during this extreme event are within ensemble spreads. While both Models have wide spreads over areas with landmass, maximum uncertainty in the atmospheric model is at hurricane eye in contrast to the wave model.

scholarly journals Research on Hydroelastic Response of an FMRC Hexagon Enclosed Platform

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1110
Author(s):  
Wei-Qin Liu ◽  
Luo-Nan Xiong ◽  
Guo-Wei Zhang ◽  
Meng Yang ◽  
Wei-Guo Wu ◽  
...  
Keyword(s):  
Time Domain ◽  
Numerical Models ◽  
Structural Response ◽  
Deep Ocean ◽  
Surface Model ◽  
Large Area ◽  
Floating Structure ◽  
Small Depth ◽  
Response Amplitude Operators ◽  
Hydroelastic Response

The numerical hydroelastic method is used to study the structural response of a hexagon enclosed platform (HEP) of flexible module rigid connector (FMRC) structure that can provide life accommodation, ship berthing and marine supply for ships sailing in the deep ocean. Six trapezoidal floating structures constitute the HEP structure so that it is a symmetrical very large floating structure (VLFS). The HEP has the characteristics of large area and small depth, so its hydroelastic response is significant. Therefore, this paper studies the structural responses of a hexagon enclosed platform of FMRC structure in waves by means of a 3D potential-flow hydroelastic method based on modal superposition. Numerical models, including the hydrodynamic model, wet surface model and finite element method (FEM) model, are established, a rigid connection is simulated by many-point-contraction (MPC) and the number of wave cases is determined. The load and structural response of HEP are obtained and analyzed in all wave cases, and frequency-domain hydroelastic calculation and time-domain hydroelastic calculation are carried out. After obtaining a number of response amplitude operators (RAOs) for stress and time-domain stress histories, the mechanism of the HEP structure is compared and analyzed. This study is used to guide engineering design for enclosed-type ocean platforms.

scholarly journals Experimental and Numerical Investigation of 3D Dam-Break Wave Propagation in an Enclosed Domain with Dry and Wet Bottom

2021 ◽  
Vol 11 (12) ◽  
pp. 5638
Author(s):  
Selahattin Kocaman ◽  
Stefania Evangelista ◽  
Hasan Guzel ◽  
Kaan Dal ◽  
Ada Yilmaz ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Numerical Models ◽  
Three Dimensional ◽  
Dam Break ◽  
Dam Failure ◽  
Navier Stokes ◽  
Negative Wave ◽  
Through Flow ◽  
Instantaneous Removal ◽  
Surface Patterns

Dam-break flood waves represent a severe threat to people and properties located in downstream regions. Although dam failure has been among the main subjects investigated in academia, little effort has been made toward investigating wave propagation under the influence of tailwater depth. This work presents three-dimensional (3D) numerical simulations of laboratory experiments of dam-breaks with tailwater performed at the Laboratory of Hydraulics of Iskenderun Technical University, Turkey. The dam-break wave was generated by the instantaneous removal of a sluice gate positioned at the center of a transversal wall forming the reservoir. Specifically, in order to understand the influence of tailwater level on wave propagation, three tests were conducted under the conditions of dry and wet downstream bottom with two different tailwater depths, respectively. The present research analyzes the propagation of the positive and negative wave originated by the dam-break, as well as the wave reflection against the channel’s downstream closed boundary. Digital image processing was used to track water surface patterns, and ultrasonic sensors were positioned at five different locations along the channel in order to obtain water stage hydrographs. Laboratory measurements were compared against the numerical results obtained through FLOW-3D commercial software, solving the 3D Reynolds-Averaged Navier–Stokes (RANS) with the k-ε turbulence model for closure, and Shallow Water Equations (SWEs). The comparison achieved a reasonable agreement with both numerical models, although the RANS showed in general, as expected, a better performance.

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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