scholarly journals ON THE CHOICE OF RANDOM WAVE SIMULATION IN THE SURF ZONE PROCESSES

2011 ◽  
Vol 1 (32) ◽  
pp. 71
Author(s):  
Jing Yuan ◽  
Ole S. Madsen
Keyword(s):  
Surf Zone ◽  
Transport Model ◽  
Bedload Transport ◽  
Random Wave ◽  
Spectral Approach ◽  
Wave Approach ◽  
Bedload Sediment ◽  
Set Up ◽  
Wave Nonlinearity ◽  
Wave Induced

In this paper, the two common approaches to account for wave randomness, the spectral approach and the wave-by-wave approach, are compared through numerical experiments conducted with the coupling of a surf zone hydrodynamic model and a bedload sediment transport model. Special attention is paid to the wave nonlinearity and net cross-shore bedload transport predictions. The two approaches are found to have negligible difference in their predictions of certain average hydrodynamics, such as wave heights, set-up and undertow. However, the wave-by-wave approach outperforms the spectral approach in the wave nonlinearity prediction, and the two approaches differ significantly in their predictions of wave-induced net cross-shore bedload transport which strongly depends on wave nonlinearity. This suggests the necessity of using the wave-by-wave approach. The computational efficiency of the wave-by-wave approach is also discussed.

scholarly journals Validation of an Experimental Procedure to Determine Bedload Transport Rates in Steep Channels with Coarse Sediment

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 672
Author(s):  
Veronica Carrillo ◽  
John Petrie ◽  
Luis Timbe ◽  
Esteban Pacheco ◽  
Washington Astudillo ◽  
...  
Keyword(s):  
Transport Model ◽  
Bedload Transport ◽  
Experimental Results ◽  
Experimental Procedure ◽  
Coarse Sediment ◽  
Sediment Size ◽  
High Gradients ◽  
Sediment Particles ◽  
Bedload Sediment ◽  
Steep Slopes

The current study presents an experimental procedure used to determine bedload sediment transport rates in channels with high gradients and coarse sediment. With the aim to validate the procedure for further investigations, laboratory experiments were performed to calculate bedload transport rates. The experiments were performed in a laboratory tilting flume with slopes ranging from 3% to 5%. The sediment particles were uniform in shape (spheres). The experiments were divided into four cases based on sediment size. Three cases of uniform sizes of 10 mm, 15 mm and 25 mm and a case with a grain size distribution formed with the uniform particle sizes were considered. From the experimental results a mathematical bedload transport model was obtained through multiple linear regression. The experimental model was compared with equations presented in the literature obtained for gravel bed rivers. The experimental results agree with some of the models presented in the literature. The closest agreement was seen with models developed for steep slopes especially for the highest slopes considered in the present study. Therefore, it can be concluded that the methodology used can be replicated for the study of bedload transport rates of channels with high gradients and coarse sediment particles to study more general cases of this process such as sediments with non-uniform shapes and sizes. However, a simplified model is proposed to estimate bedload transport rates for slopes up to 5%.

scholarly journals VARIATION OP LONGSHORE CURRENT ACROSS THE SURF ZONE

1970 ◽  
Vol 1 (12) ◽  
pp. 18 ◽  
Author(s):  
Edward B. Thornton
Keyword(s):  
Surf Zone ◽  
Engineering Practice ◽  
Longshore Current ◽  
Current Variation ◽  
Excess Momentum ◽  
Shoaling Waves ◽  
Set Up ◽  
Spilling Breakers ◽  
Wave Induced ◽  
The Waves

The wave-induced longshore current variation across the surf zone is described for a simplified model The basic assumptions are that the conditions are steady, the bottom contours are straight and parallel but allow for an arbitrary bottom profile, the waves are adequately described by linear theory, and that spilling breakers exist across the surf zone Conservation equations of mass, momentum, and energy, separated into the steady and unsteady components, are used to describe second order-wave-induced phenomena of shoaling waves approaching at an angle to the beach An expression for the longshore current is developed, based on the alongshore component of excess momentum flux due to the presence of unsteady wave motion Wave set-down and set-up have been included in the formulation Emphasis in the analysis is placed on formulating usable predictive equations for engineering practice Comparison with experimental results from the laboratory and field show that if the assumed conditions are approximately fulfilled, the predicted results compare quite favorably.

scholarly journals A NUMERICAL MODEL OF NEARSHORE CURRENTS BASED ON A FINITE AMPLITUDE WAVE THEORY

1986 ◽  
Vol 1 (20) ◽  
pp. 64 ◽  
Author(s):  
Masataka Yamaguchi
Keyword(s):  
Numerical Model ◽  
Surf Zone ◽  
Wave Theory ◽  
Quantitative Agreement ◽  
Finite Amplitude ◽  
Wave Transformation ◽  
Current Profile ◽  
Nearshore Currents ◽  
Wave Nonlinearity ◽  
Wave Induced

A numerical model of wave-Induced nearshore currents taking into account the finite amplitude effect is developed, with a cnoidal wave theory used for the estimation of wave characteristics. The model is applied to the computation of wave transformation and nearshore currents on uniformly sloping beaches and on two-dimensional model topographies. The comparison with the results obtained by a linear model shows that wave nonlinearity has a strong influence on wave transformation in shoaling water and in the surf zone and on the strength of nearshore circulation, but that it does not have much effect on the longshore current profile. Moreover, the validity of the present model is supported by the quantitative agreement with the experiment for wave height variations, and the qualitative correspondence with the experiment for mean water level variation and longshore currents and the observation for nearshore currents.

scholarly journals MODELING MORPHOLOGICAL EVOLUTION IN THE VICINITY OF COASTAL STRUCTURES

2011 ◽  
Vol 1 (32) ◽  
pp. 68 ◽  
Author(s):  
Pham Thanh Nam ◽  
Magnus Larson ◽  
Hans Hanson
Keyword(s):  
Sediment Transport ◽  
Large Scale ◽  
Transport Model ◽  
Morphological Evolution ◽  
Transformation Model ◽  
Quality Data ◽  
Wave Transformation ◽  
Random Wave ◽  
Army Corps ◽  
Wave Induced

A numerical model of beach topography evolution was developed. The model includes five sub-models: random wave transformation model, surface roller model, wave-induced current model, sediment transport model, and morphological change model. The model was validated by two unique high-quality data sets obtained from experiments on the morphological impact of a detached breakwater and a T-head groin in the basin of the Large-scale Sediment Transport Facility (LSTF) at the US Army Corps of Engineer Research and Development Center in Vicksburg, Miss. The simulations demonstrated that the model well reproduced the wave conditions, wave-induced currents, and morphological evolution in the vicinity of the structures.

Effects of Cnoidal Wave-Induced Seepage on Vertical Breakwater Resting on Permeable Elastic Seabed

2014 ◽  
Vol 716-717 ◽  
pp. 284-288
Author(s):  
Jian Kang Yang ◽  
Hua Huang ◽  
Lin Guo ◽  
Jing Rong Lin ◽  
Qing Yong Zhu ◽  
...  
Keyword(s):  
Shallow Water ◽  
Wave Theory ◽  
Cnoidal Wave ◽  
Load Prediction ◽  
Wave Load ◽  
Seepage Pressure ◽  
Theoretical Investigations ◽  
Nonlinearity Effect ◽  
Wave Nonlinearity ◽  
Wave Induced

Theoretical investigations on cnoidal waves interacting with breakwater resting on permeable elastic seabed are presented in this paper. Based on the shallow water reflected wave theory and Biot consolidation theory on wave-induced seepage pressure, the analytical solutions to first order cnoidal wave reflection and wave-induced seepage pressure are obtained by the eigenfunction expansion approach. Numerical results are presented to show the effects of depth of water, breakwater geometry on cnoidal wave-induced seepage uplift force and overturning moment. Compared with Airy wave theory, in certain shallow water conditions, the shallow water wave theory can more effectively illustrate wave nonlinearity effect in wave load prediction.

scholarly journals FIELD MEASUREMENTS AND MODELLING OF NEARSHORE CURRENTS AT A HIGH-ENERGY GEOLOGICALLY-CONSTRAINED BEACH

2020 ◽  
pp. 18
Author(s):  
Arthur Mouragues ◽  
Philippe Bonneton ◽  
Bruno Castelle ◽  
Vincent Marieu
Keyword(s):  
Surf Zone ◽  
Low Frequency ◽  
Field Measurements ◽  
High Energy ◽  
Oblique Wave ◽  
Wave Forcing ◽  
Circulation Patterns ◽  
Wave Conditions ◽  
Nearshore Currents ◽  
Set Up

We present field measurements of nearshore currents at a high-energy mesotidal beach with the presence of a 500-m headland and a submerged reef. Small changes in wave forcing and tide elevation were found to largely impact circulation patterns. In particular, under 4-m oblique wave conditions, our measurements indicate the presence of an intense low-frequency fluctuating deflection rip flowing against the headland and extending well beyond the surf zone. An XBeach model is further set up to hindcast such flow patterns.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/EiqnjBIkWJE

scholarly journals Wave-Induced Sediment Motion Beyond the Surf Zone: Case Study of Lubiatowo (Poland)

2015 ◽  
Vol 62 (1-2) ◽  
pp. 27-39 ◽  
Author(s):  
Grzegorz R. Cerkowniak ◽  
Rafał Ostrowski ◽  
Magdalena Stella
Keyword(s):  
Surf Zone ◽  
Shear Stresses ◽  
Research Station ◽  
Wave Parameters ◽  
Sea Bottom ◽  
Theoretical Investigations ◽  
Deep Water Wave ◽  
Offshore Wave ◽  
Wave Induced

AbstractThe paper presents results of field and theoretical investigations of a natural sandy shore located near the IBW PAN Coastal Research Station in Lubiatowo (Poland, the south Baltic Sea). The study site displays multi-bar cross-shore profiles that intensively dissipate wave energy, mostly by breaking. The main field data comprise offshore wave parameters and three cross-shore bathymetric profiles. Waveinduced nearbed velocities and bed shear stresses are theoretically modelled for weak, moderate, strong and extreme storm conditions to determine sediment motion regimes at various locations on the seaward boundary of the surf zone. The paper contains a discussion on the depth of closure concept, according to which the offshore range of sea bottom changes can be determined by the extreme seasonal deep-water wave parameters.

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