scholarly journals MODELING OF WAVE-CURRENT INTERACTION USING A MULTIDIRECTIONAL WAVE-ACTION BALANCE EQUATION

2011 ◽  
Vol 1 (32) ◽  
pp. 47 ◽  
Author(s):  
Yan Ding ◽  
Sam S. Y. Wang
Keyword(s):  
Balance Equation ◽  
Wave Model ◽  
Tidal Currents ◽  
Wave Action ◽  
Observation Data ◽  
Action Model ◽  
Current Interaction ◽  
Ambient Currents ◽  
Multidirectional Wave ◽  
River Mouths

This study presents an integrated numerical model to simulate wave deformation/transformation in tidal inlets or river mouths with ambient currents (e.g. tidal currents, river inflows) by carefully modeling the effect of wave-current interaction. A multidirectional wave-action balance equation is used to compute random/directional wave processes such as diffraction, refraction, shoaling, wave breaking, as well as wave-current interaction. This wave action model is coupled with a two-dimensional hydrodynamic model, the feedback effect of wave and current can be effectively simulated. This model is validated by simulating wave laboratory experiments in an inlet entrance, and waves and tidal currents in Grays Harbor, WA by using available field observation data in 1999. The capabilities of the wave model for simulating wave-current interaction and the corresponding breaking effect are confirmed in the study.

Numerical Simulation of Wave Transformation Using Spectral Wave Action Model

2014 ◽  
Vol 638-640 ◽  
pp. 1261-1265 ◽  
Author(s):  
Yun Peng Zhang ◽  
Ming Liang Zhang ◽  
Zi Ning Hao ◽  
Yuan Yuan Xu ◽  
Yang Qiao
Keyword(s):  
Coastal Waters ◽  
Real Life ◽  
Wave Model ◽  
Wave Action ◽  
Wave Transformation ◽  
Wind Effect ◽  
Random Wave ◽  
Action Model ◽  
Averaged Model ◽  
Transformation Processes

This paper presents a spectral wave action model to simulate random wave deformation and transformation. The wave model is based on the wave action balance equation and can simulate wave fields by accounting for wave breaking, shoaling, refraction, diffraction and wind effect in coastal waters. It is a finite-difference, phase averaged model for the steady-state wave spectral transformation. The wave model is applied to verify different experimental cases and real life case of considering the several factor effects. The calculated results agree with the experimental and field data. The results show that the wave model presented herein should be useful in simulating the wave transformation processes in complicated coastal waters.

Verifications of Diffraction Modeling Capability in a Coastal Spectral Wave Model

2009 ◽  
Author(s):  
Jinhai Zheng ◽  
Yu Tang
Keyword(s):  
Balance Equation ◽  
Wave Diffraction ◽  
Process Model ◽  
Present Model ◽  
Wave Process ◽  
Wave Structure ◽  
Wave Model ◽  
Wave Action ◽  
Random Wave ◽  
Spectral Wave Model

WABED (Wave Action Balance Equation with Diffraction) is a 2-D coastal spectral wave process model and used in the development of a practice-oriented random wave prediction for coastal engineering studies at inlets, navigation projects, and wave-structure interactions. Wave diffraction is implemented by adding a term derived from the parabolic wave equation to the wave action balance equation. This paper describes the evaluation of the modeling capability to represent wave diffraction available in the WABED, which is accomplished by testing the present model for diffraction-prone cases such as the wave field of a gap in an infinitely long breakwater and that over an elliptical shoal. Computations are compared with experimental observations and Sommerfeld’s analytical solutions. Comparisons indicate that WABED performs reasonable well in these conditions and is capable of predicting wave diffraction effectively together with refraction and shoaling.

scholarly journals Evaluating skill of BMKG wave model forecast (Wavewatch-3) with observation data in Indian Ocean (5 – 31 December 2017).

2021 ◽  
Vol 893 (1) ◽  
pp. 012058
Author(s):  
R Kurniawan ◽  
H Harsa ◽  
A Ramdhani ◽  
W Fitria ◽  
D Rahmawati ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Wave Height ◽  
Model Performance ◽  
Forecast Accuracy ◽  
Wave Model ◽  
Ocean Waves ◽  
Observation Data ◽  
Operating Characteristics ◽  
Wave Forecast ◽  
Good For

Abstract Providing Maritime meteorological forecasts (including ocean wave information) is one of BMKG duties. Currently, BMKG employs Wavewatch-3 (WW3) model to forecast ocean waves in Indonesia. Evaluating the wave forecasts is very important to improve the forecasts skill. This paper presents the evaluation of 7-days ahead BMKG’s wave forecast. The evaluation was performed by comparing wave data observation and BMKG wave forecast. The observation data were obtained from RV Mirai 1708 cruise on December 5th to 31st 2017 at the Indian Ocean around 04°14'S and 101°31'E. Some statistical properties and Relative Operating Characteristics (ROC) curve were utilized to assess the model performance. The evaluation processes were carried out on model’s parameters: Significant Wave Height (Hs) and Wind surface for each 7-days forecast started from 00 UTC. The comparation results show that, in average, WW3 forecasts are over-estimate the wave height than that of the observation. The forecast skills determined from the correlation and ROC curves are good for the first- and second-day forecast, while the third until seventh day decrease to fair. This phenomenon is suspected to be caused by the wind data characteristics provided by the Global Forecasts System (GFS) as the input of the model. Nevertheless, although statistical correlation is good for up to 2 days forecast, the average value of Root Mean Square Error (RMSE), absolute bias, and relative error are high. In general, this verifies the overestimate results of the model output and should be taken into consideration to improve BMKG’s wave model performance and forecast accuracy.

Effect of Uni- and Bi-Directional Coupling of Ocean-Met Interaction on Significant Wave Height and Local Wind

2017 ◽  
Author(s):  
Adil Rasheed ◽  
Jakob Kristoffer Süld ◽  
Mandar Tabib
Keyword(s):  
Wave Height ◽  
Significant Wave Height ◽  
Surface Wind ◽  
Wave Model ◽  
Ocean Surface ◽  
Observation Data ◽  
Local Wind ◽  
Near Surface ◽  
Significant Wave ◽  
Bidirectional Coupling

Accurate prediction of near surface wind and wave height are important for many offshore activities like fishing, boating, surfing, installation and maintenance of marine structures. The current work investigates the use of different methodologies to make accurate predictions of significant wave height and local wind. The methodology consists of coupling an atmospheric code HARMONIE and a wave model WAM. Two different kinds of coupling methodologies: unidirectional and bidirectional coupling are tested. While in Unidirectional coupling only the effects of atmosphere on ocean surface are taken into account, in bidirectional coupling the effects of ocean surface on the atmosphere are also accounted for. The predicted values of wave height and local wind at 10m above the ocean surface using both the methodologies are compared against observation data. The results show that during windy conditions, a bidirectional coupling methodology has better prediction capability.

Numerical Simulation and Practical Sand Silting in Waterways of Langya Bay

2008 ◽  
Author(s):  
Lin Zhao ◽  
Bingchen Liang ◽  
Hongda Shi ◽  
Xiangzhu Liu
Keyword(s):  
Wave Model ◽  
Water Levels ◽  
Open Boundary ◽  
Observation Data ◽  
Surface Drag ◽  
Time And Space ◽  
Sediment Distribution ◽  
Waves And Currents ◽  
Basin Water ◽  
Sediment Model

Dongjiakou Harbor is located at the Langya Bay in the city of Qingdao, Shandong Province. It is a multi-functional harbor of heavy passing capacity under planning in China. The sediment distribution and dispersion in the waterways and harbor basin water areas is of great importance to the construction and operation of the harbor. This article is based on the measurement of waves and currents as well as sediment suspension characteristics on site, and using numerical methods to predict the dispersion and deposition rules in this area. A combined wave-current-sediment model of COHERENS-SED is created through the combination of hydrodynamic model COHERENS and wave model SWAN as well as a sedimentation model SED developed by the authors. Inside COHERENS-SED, SWAN is regarded as a subroutine and it gets time and space varying current velocity and surface elevation from COHERENS. COHERENS gets time and space varying wave relevant parameters calculated by SWAN. Wave-enhanced bottom stress, wave dependent surface drag coefficient and radiation stress are introduced to COHERENS. Then a fully coupled hydrodynamic–sediment model COHERENS-SED accounting for interaction between the waves and currents is obtained and adopted to simulate these hydrodynamic conditions and the sedimentation processes in Langya Bay area. The open boundary of waves and currents is obtained through nesting from running a wider model which includes the Bohai Sea and the North Yellow Sea with coarser solution and contains coastal regions of Shandong Peninsula which includes the whole area of Langya Bay. Generally, the values of time series of current velocities, current directions and water levels as well as sediment concentrations have good agreements with observation data. The study shows the currents in the waterways and harbor basin water areas are relatively weak due to the narrow water width at the port mouth and the current directions parallel to the wharf directions. Also, sediment dispersion scales and strength are predicted according to the computation. The study also estimates the average sediment deposition amount and seabed erosion in this area. Besides, significant wave height and wave period obtained by COHERENS-SWAN shows that simulation result with wave-current interaction is better agreed with the measurement than the case without current.

scholarly journals A Near-Shore Linear Wave Model with the Mixed Finite Volume and Finite Difference Unstructured Mesh Method

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 199
Author(s):  
Yong G. Lai ◽  
Han Sang Kim
Keyword(s):  
Finite Difference ◽  
Finite Volume ◽  
Current Model ◽  
Wave Model ◽  
Wave Action ◽  
New Wave ◽  
Near Shore ◽  
The One ◽  
Geographical Space ◽  
Model Approach

The near-shore and estuary environment is characterized by complex natural processes. A prominent feature is the wind-generated waves, which transfer energy and lead to various phenomena not observed where the hydrodynamics is dictated only by currents. Over the past several decades, numerical models have been developed to predict the wave and current state and their interactions. Most models, however, have relied on the two-model approach in which the wave model is developed independently of the current model and the two are coupled together through a separate steering module. In this study, a new wave model is developed and embedded in an existing two-dimensional (2D) depth-integrated current model, SRH-2D. The work leads to a new wave–current model based on the one-model approach. The physical processes of the new wave model are based on the latest third-generation formulation in which the spectral wave action balance equation is solved so that the spectrum shape is not pre-imposed and the non-linear effects are not parameterized. New contributions of the present study lie primarily in the numerical method adopted, which include: (a) a new operator-splitting method that allows an implicit solution of the wave action equation in the geographical space; (b) mixed finite volume and finite difference method; (c) unstructured polygonal mesh in the geographical space; and (d) a single mesh for both the wave and current models that paves the way for the use of the one-model approach. An advantage of the present model is that the propagation of waves from deep water to shallow water in near-shore and the interaction between waves and river inflows may be carried out seamlessly. Tedious interpolations and the so-called multi-model steering operation adopted by many existing models are avoided. As a result, the underlying interpolation errors and information loss due to matching between two meshes are avoided, leading to an increased computational efficiency and accuracy. The new wave model is developed and verified using a number of cases. The verified near-shore wave processes include wave shoaling, refraction, wave breaking and diffraction. The predicted model results compare well with the analytical solution or measured data for all cases.

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.

Extended energy-balance-equation wave model for multidirectional random wave transformation

2005 ◽  
Vol 32 (8-9) ◽  
pp. 961-985 ◽  
Author(s):  
Hajime Mase ◽  
Kazuya Oki ◽  
Terry S. Hedges ◽  
Hua Jun Li
Keyword(s):  
Energy Balance ◽  
Balance Equation ◽  
Wave Model ◽  
Energy Balance Equation ◽  
Wave Transformation ◽  
Random Wave
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