Mixing induced by ISWs breaking over a sloping boundary: an analytical heuristic model

2020 ◽  
Author(s):  
Davide Cavaliere ◽  
Giovanni la Forgia ◽  
Federico Falcini
Keyword(s):  
Laboratory Experiments ◽  
Nonlinear Models ◽  
Wave Model ◽  
Real Field ◽  
Mixing Efficiency ◽  
Layer System ◽  
Geophysical Research ◽  
Strongly Nonlinear ◽  
Symmetric Density ◽  
Definition Of

<p>We propose an analytical approach to estimate mixing efficiency in Internal Solitary Waves (ISWs) breaking processes. We make use of the theoretical framework of Winters et al. [1995] to describe the energetics of a stratified fluid flow, calculating the Available Potential Energy (APE) of an ISW of depression in a two-layer system, assuming that the symmetric density structure on both sides of the feature is exactly the same. Starting from the definition of mixing efficiency given by Michallet and Ivey [1999], through the Ozmidov and Thorpe length-scales we derive an expression for the mixing efficiency avoiding the use of any wave model (as KdV-type models or strongly nonlinear models) to estimate the wave energy. The model is successfully verified through laboratory experiments performed in a wave tank and is meant to be applied by using real field CTD casts.</p><p> </p><p>References:</p><p>Winters, K., Lombard, P., Riley, J., and D’Asaro, E. (1995). <em>Available potential</em></p><p><em>energy and mixing in density-stratified fluids</em>. J. Fluid Mech., 289, 115-128.</p><p>Michallet, H. and Ivey, G. (1999). <em>Experiments on mixing due to internal solitary</em></p><p><em>waves breaking on uniform slopes</em>. Journal of Geophysical Research: Oceans,</p><p>104(C6), 13467-13477</p>

Mixing in Symmetric Holmboe Waves

2007 ◽  
Vol 37 (6) ◽  
pp. 1566-1583 ◽  
Author(s):  
W. D. Smyth ◽  
J. R. Carpenter ◽  
G. A. Lawrence
Keyword(s):  
Shear Layer ◽  
Effective Viscosity ◽  
Laboratory Experiments ◽  
Density Difference ◽  
Transition To Turbulence ◽  
Mixing Efficiency ◽  
Effective Diffusivities ◽  
Key Parameter

Abstract Direct simulations are used to study turbulence and mixing in Holmboe waves. Previous results showing that mixing in Holmboe waves is comparable to that found in the better-known Kelvin–Helmholtz (KH) billows are extended to cover a range of stratification levels. Mixing efficiency is discussed in detail, as are effective diffusivities of buoyancy and momentum. Entrainment rates are compared with results from laboratory experiments. The results suggest that the ratio of the thicknesses of the shear layer and the stratified layer is a key parameter controlling mixing. With that ratio held constant, KH billows mix more rapidly than do Holmboe waves. Among Holmboe waves, mixing increases with increasing density difference, despite the fact that the transition to turbulence is delayed or prevented entirely by the stratification. Results are summarized in parameterizations of the effective viscosity and diffusivity of Holmboe waves.

scholarly journals Inclusion of landslide tsunamis generation into a depth integrated wave model

2010 ◽  
Vol 10 (11) ◽  
pp. 2259-2268 ◽  
Author(s):  
C. Cecioni ◽  
G. Bellotti
Keyword(s):  
Field Equation ◽  
Small Amplitude ◽  
Laboratory Experiments ◽  
Three Dimensional ◽  
Wave Model ◽  
Dispersive Equations ◽  
Far Field ◽  
Mild Slope Equation ◽  
Calculation Results ◽  
Propagation Of Waves

Abstract. A numerical model based on the mild slope equation, suitable to reproduce the propagation of small amplitude tsunamis in the far field, is extended to reproduce the generation and the propagation of waves generated by landslides. The wave generation is modeled through a forcing term included in the field equation, which reproduces the effects of the movement of a submerged landslide on the fluid. The measurements of three dimensional laboratory experiments, which simulate tsunamis generated by landslide sliding along the flank of a conical island, are compared with the theoretical calculation results. The present approach is also compared with the similar method of Tinti et al. (2006) used for the generation of these waves in depth integrated model, and the different behavior when using frequency-dispersive and non-dispersive equations is highlighted.

Wind waves modeling in the polar law weather conditions

2020 ◽  
Author(s):  
Alexandra Kuznetsova ◽  
Evgeny Poplavsky ◽  
Nikita Rusakov ◽  
Yuliya Troitskaya
Keyword(s):  
Wind Waves ◽  
Rapid Development ◽  
Free Water ◽  
Wave Model ◽  
Weather Conditions ◽  
Reanalysis Data ◽  
The Arctic ◽  
Geophysical Research ◽  
Polar Lows ◽  
Adverse Weather

<p>Arctic storms pose a great danger to developing commercial and passenger shipping, coastal infrastructure, and also for oil production from offshore platforms. This is primarily due to high waves and extreme winds. Such episodes of adverse weather conditions due to their rapid development are poorly predicted by modern models. For this purpose, the representation of the event of polar law is studied in the wave model WAVEWATCH III.</p><p>Wind waves were simulated under conditions of polar depression on ice-free water. To simulate wind waves under conditions of polar depression, the Barents Sea was selected, where, according to the data of [1, 2], a large number of polar hurricanes are observed. Among the identified polar hurricanes, for example, in [3], a hurricane that took place on 05.02.2009, observed at coordinates 69 N 40 E is chosen. The preliminary results in the wave model are obtained without the ice influence consideration. The developed model was configured using the CFSR wind reanalysis data. The resulting distribution of significant wave heights is obtained. Then, to consider the attenuation by sea ice, the reanalysis data of the Arctic System Reanalysis Version 2 (ASRv2), which is based on Polar WRF with a resolution of 15 km for the Arctic region, is used. Modeling the destruction of ice by waves during an intense arctic storm will be implemented using WW3 models with an IS2 module.</p><p>The work is supported by RFBR grant 18-05-60299.</p><ol><li>Smirnova, J. E., Golubkin, P. A., Bobylev, L. P., Zabolotskikh, E. V., & Chapron, B. (2015). Polar low climatology over the Nordic and Barents seas based on satellite passive microwave data. Geophysical Research Letters, 42(13), 5603-5609.</li> <li>Smirnova, J., & Golubkin, P. (2017). Comparing polar lows in atmospheric reanalyses: Arctic System Reanalysis versus ERA-Interim. Monthly Weather Review, 145(6), 2375-2383.</li> <li>Noer, G., & Lien, T. (2010). Dates and Positions of Polar lows over the Nordic Seas between 2000 and 2010. Norwegian Meteorological Institute Rep.</li> </ol>

A combined computational algorithm for solving the problem of long surface waves runup on the shore

2016 ◽  
Vol 31 (4) ◽  
Author(s):  
Yurii I. Shokin ◽  
Alexander D. Rychkov ◽  
Gayaz S. Khakimzyanov ◽  
Leonid B. Chubarov
Keyword(s):  
Numerical Simulation ◽  
Shallow Water ◽  
Nonlinear Waves ◽  
Laboratory Experiments ◽  
Computational Algorithm ◽  
Analytic Solutions ◽  
Shallow Water Theory ◽  
Sph Method ◽  
Weakly Nonlinear ◽  
Strongly Nonlinear

AbstractIn the present paper we study features and abilities of the combined TVD+SPH method relative to problems of numerical simulation of long waves runup on a shore within the shallow water theory. The results obtained by this method are compared to analytic solutions and to the data of laboratory experiments. Examples of successful application of the TVD+SPH method are presented for the case of study of runup processes for weakly nonlinear and strongly nonlinear waves, and also for

scholarly journals BREAKING WAVE DESIGN CRITERIA

1984 ◽  
Vol 1 (19) ◽  
pp. 2
Author(s):  
E.B. Thornton ◽  
C.S. Wu ◽  
R.T. Guza
Keyword(s):  
Wave Breaking ◽  
Laboratory Experiments ◽  
Wave Model ◽  
Rayleigh Distribution ◽  
The United States ◽  
Random Wave ◽  
Breaking Wave ◽  
Shore Protection ◽  
Design Procedures ◽  
Wave Heights

Breaking wave heights measured in both field and random wave laboratory experiments are examined. The dependence of breaker height and breaker depth on beach slope and deep water steepness is presented. The results are compared with the design curves of the Shore Protection Manual (SPM) and the predictions of the randan wave model by Goda (1975). The comparisons indicate that the significant breaker height, based on Goda's model, is slightly conservative for the experimental cases; but the maximum breaker heights are reasonably predicted by the model. The design procedures in the SPM are based on a monochromatic wave breaking, and appear overly conservative, particularly for low wave steepness (less than 0.01) which occur frequently on the West Coast of the United States. The use of the Rayleigh distribution to predict wave height statistics is tested with random wave data for both deep and shallow water regions.

Periodic Steady State Response of Complex Vehicle Models Using Multi-Level Substructuring

2007 ◽  
Author(s):  
I. Stavrakis ◽  
C. Theodosiou ◽  
S. Natsiavas
Keyword(s):  
Nonlinear Models ◽  
Equations Of Motion ◽  
Response Spectra ◽  
Computationally Efficient ◽  
Sparsity Pattern ◽  
Strongly Nonlinear ◽  
Road Excitation ◽  
Multi Level ◽  
Set Up ◽  
Coordinate Reduction

A systematic methodology is presented for investigating long term ride dynamics of large order vehicle models in a computationally efficient way. First, the equations of motion for each of the main structural components of the vehicle are set up by applying the finite element method. As a consequence of the geometric complexity of these components, the number of the resulting equations is so high that the classical coordinate reduction methodologies become numerically ineffective to apply. In addition, the composite model possesses strongly nonlinear characteristics. However, the method applied overcomes some of these difficulties by imposing a multi-level substructuring procedure, based on the sparsity pattern of the stiffness matrix. In this way, the number of the equations of motion of the complete system is substantially reduced. Subsequently, this allows the application of appropriate numerical methodologies for predicting response spectra of the nonlinear models to periodic road excitation. Results obtained by direct integration of the equations of motion are also presented. Where possible, the accuracy and validity of the applied methodology is verified by comparison with results obtained for the original models.

scholarly journals Layering in a Flow with Diffusively Stable Temperature and Salinity Stratification

2006 ◽  
Vol 36 (7) ◽  
pp. 1457-1470 ◽  
Author(s):  
Juan Ezequiel Martin ◽  
Chris R. Rehmann
Keyword(s):  
Laboratory Experiments ◽  
Density Ratio ◽  
Mixing Efficiency ◽  
Differential Diffusion ◽  
Salinity Stratification ◽  
Eddy Diffusivities ◽  
Stable Temperature ◽  
Work Input ◽  
The Difference ◽  
Rate Of Dissipation

Abstract Laboratory experiments were conducted to study the formation of layers and interfaces in a fluid stratified with two scalars. Fluid with initially linear, diffusively stable temperature and salinity profiles was stirred using an arrangement of horizontally oscillating, vertical rods. Layers occurred when the density ratio, or the ratio of the contributions of temperature and salinity to the density gradient, was small, but they did not form in similar conditions of turbulence intensity and stratification strength when the density ratio was large. The difference in behavior is ascribed to differential diffusion, or the preferential transport of temperature, which occurred in all of the experiments. Eddy diffusivities were linearly proportional to ɛa/νN 2, where ɛa is an averaged rate of dissipation of turbulent kinetic energy. The mixing efficiency, computed as the ratio of potential energy change to work input to the system, increased with the density ratio. As previous researchers have found, the Phillips–Posmentier mechanism describes the final layered state but not the initial, evolving states of the system.

Prediction methods for coning process

2021 ◽  
pp. 18-25
Author(s):  
E.F. Veliyev ◽  
Keyword(s):  
Computer Modeling ◽  
Analytical Approach ◽  
Laboratory Experiments ◽  
Numerical Approach ◽  
Prediction Methods ◽  
Field Development ◽  
The Third ◽  
Modern Methods ◽  
Definition Of

Currently, the percentage of the mature fields steadily rise and the process of formation of water and gas cones becomes unavoidable. The prediction of this process is essential for successful field development. Correlation dependencies developed for this purpose can be divided into three main groups. The models in the first group are based on the analytical approach of definition of balance conditions for viscous and gravitational powers in the reservoir. The methods in the second group are based on empiric approach, i.e. on the data obtained as a result of laboratory experiments or computer modeling. The methods in the third group are based on numerical approach. The paper presents the analysis and classification of modern methods for prediction of coning process.

Nonlinear models for design of circular RC columns under ultimate and service states

2021 ◽  
Author(s):  
Helena Barros ◽  
Carla Ferreira ◽  
Joaquim Figueiras ◽  
Mário Pimentel
Keyword(s):  
Reinforced Concrete ◽  
Nonlinear Models ◽  
Bending Moment ◽  
Constitutive Law ◽  
Equilibrium Equations ◽  
Linear Elastic ◽  
Compressive Stresses ◽  
Steel Bar ◽  
Tension And Compression ◽  
Definition Of

<p>The present paper is dedicated to the ultimate and to the service design of circular reinforced concrete sections under axial load and bending moment, according to Eurocode 2 [1].</p><p>The objective of the present work is to develop design equations for circular reinforced concrete sections, solving the equilibrium equations by mathematic symbolic software. The concrete only supports compressive stresses and the steel can hold both tension and compression. The nonlinear equation of EC2 [1] is used for compressed concrete in the ultimate design. The steel is considered to have a linear elastic constitutive law up to the yield stress, followed by a plastic behaviour. The ultimate design condition is posed in terms of maximum strains for the most compressed concrete fibre or for the tensioned steel bar, permitting the definition of interaction abacuses, shown in the present paper.</p>

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