scholarly journals ON THE GEOMETRY OF RIPPLES DUE TO WAVES

1978 ◽  
Vol 1 (16) ◽  
pp. 107 ◽  
Author(s):  
M.S. Yalin ◽  
E. Karahan
Keyword(s):  
Wind Waves ◽  
Laboratory Data ◽  
Specific Weight ◽  
Oscillatory Motion ◽  
Shallow Waters ◽  
Present Formulation ◽  
Unidirectional Flow ◽  
Single Curve ◽  
Bed Material

The present paper is an attempt to determine a single curve for the prediction of the length of ripples forming due to wind waves in shallow waters. The curve is revealed by normalising the field and laboratory data supplied by various authors. The concept of the unified plot embodied by the single curve mentioned is developed by using dimensional methods and by considering the fact that the specific weight and the density of the cohesionless bed material do not affect the length of ripples in a detectable manner. It is shown that the present formulation of the length of ripples due to waves satisfies the requirement of transition into the corresponding formulation of the unidirectional flow ripples when the period and the amplitude of the oscillatory motion increase indefinitely, while their ratio (implying "the velocity") remains finite.

scholarly journals THE ONE-DIMENSIONAL WAVE SPECTRA AT LIMITED FETCH

1972 ◽  
Vol 1 (13) ◽  
pp. 13
Author(s):  
Hisashi Mitsuyasu
Keyword(s):  
Similarity Theory ◽  
Wind Waves ◽  
Laboratory Data ◽  
Peak Frequency ◽  
Wave Spectra ◽  
One Dimensional ◽  
Wide Range ◽  
Laboratory Tank ◽  
The One ◽  
Dimensional Wave

The data for the spectra of wind-generated waves measured in a laboratory tank and in a bay are analyzed using the similarity theory of Kitaigorodski, and the one-dimensional spectra of fetch-limited wind waves are determined from the data. The combined field and laboratory data cover such a wide range of dimensionless fetch F (= gF/u2 ) as F : 102 ~ 10 . The fetch relations for the growthes of spectral peak frequency u)m and of total energy E of the spectrum are derived from the proposed spectra, which are consistent with those derived directly from the measured spectra.

scholarly journals Empirical Studies in Alluvial Streams

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Levent Yilmaz
Keyword(s):  
Single Channel ◽  
Empirical Studies ◽  
Laboratory Data ◽  
Fine Sediments ◽  
Channel Interaction ◽  
Variable Curvature ◽  
Alluvial Channel ◽  
Channel Patterns ◽  
Bed Material ◽  
River Meandering

Meander flow takes place in one single channel which oscillates more orless regularly with amplitudes that tend to increase with time. Meandersare found in beds of fine sediments with gentle slopes. In this study, effortwill be made to investigate meanders’ turbulent boundary layer and toimprove the present knowledge about the river meandering phenomena. Itis assumed that the development of the perturbations which develop intomeanders or braids, is longer than the width of the channel. Interaction between the flow and mobile boundaries produces channel patterns which areclassified as meandering or braided. It is therefore long compared with theripples or dunes which cover the bed of such a channel and whose wavelength is shorter than the width of the channel. The variation of resistance toflow and rate of transport of bed material with velocity are discussed brieflyand taken into account. Meander flow and meander shear stress distribution of the channel are described. The basis is a steady, two-dimensionalmodel of flow in an alluvial channel with variable curvature. The meanderdevelopment is described by forcing a travelling, small-amplitude channelalignment wave on the system, and determining the growth characteristicsof the wave. Laboratory data are used to verify the formulas.

scholarly journals Drag Force Modeling of Surface Wave Dissipation by a Vegetation Field

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2513
Author(s):  
Tze-Yi Yang ◽  
I-Chi Chan
Keyword(s):  
Numerical Experiments ◽  
Open Space ◽  
Wind Waves ◽  
Laboratory Data ◽  
Storm Surges ◽  
Coastal Vegetation ◽  
Force Modeling ◽  
Wave Height Attenuation ◽  
Large Wind ◽  
Natural Barrier

In this paper, we explore the use of coastal vegetation as a natural barrier to defend our shoreline from hazards caused by large wind waves, storm surges, and tsunamis. A numerical model based on XBeach is employed to evaluate the wave damping by vegetation. An explicit formula for the required drag coefficient used to help describe the additional force imposed by the vegetation is developed through a series of numerical experiments. Overall, our predictions agree reasonably with available laboratory data in the literature for various incident wave conditions and vegetation configurations. Our analysis suggests that a small unvegetated open space in the middle of a vegetation strip does not have a significant impact on the amount of wave height attenuation at the exit of the vegetated bed.

On the wind-induced growth of slow water waves of finite steepness

2008 ◽  
Vol 608 ◽  
pp. 243-274 ◽  
Author(s):  
WILLIAM L. PEIRSON ◽  
ANDREW W. GARCIA
Keyword(s):  
Tangential Stress ◽  
Growth Rates ◽  
Water Waves ◽  
Dynamic Range ◽  
Wind Waves ◽  
Laboratory Data ◽  
Quantitative Agreement ◽  
Wave Drag ◽  
Wave Growth ◽  
Wave Range

Determining characteristic growth rates for water waves travelling more slowly than the wind has continued to be a key unresolved problem of air–sea interaction for over half a century. Analysis of previously reported and recently acquired laboratory wave data shows a systematic decline in normalized wave growth with increasing mean wave steepness that has not previously been identified. The normalized growth dynamic range is comparable with previously observed scatter amongst other laboratory data gathered in the slow wave range. Strong normalized growth rates are observed at low wave steepnesses, implying an efficient wave-coherent tangential stress contribution. Data obtained during this study show quantitative agreement with the predictions of others of the interactions between short wind waves and the longer lower-frequency waves. Measured normalized wave growth rates are consistent with numerically predicted growth due to wave drag augmented by significant wave-coherent tangential stress.

scholarly journals LONGSHORE TRANSPORT OF SUSPENDED SEDIMENT

1972 ◽  
Vol 1 (13) ◽  
pp. 53 ◽  
Author(s):  
John C. Fairchild
Keyword(s):  
Suspended Sediment ◽  
Surf Zone ◽  
Laboratory Data ◽  
Sediment Concentration ◽  
Nozzle Height ◽  
Unidirectional Flow ◽  
Longshore Transport ◽  
Average Sampling ◽  
Scatter Plots ◽  
The City

In excess of 800 suspended sediment samples were collected from stations along the City Pier, Ventnor, New Jersey and Jennettes Pier, Nags Head, North Carolina using a tractor-mounted pump sampler. Most samples were collected within the surf zone at the Ventnor site. At the Nags Head site, sample collections included the surf zone, but generally extended over a wider range of the nearshore zone. Average sampling time was 3 minutes. Nozzle elevation varied from 3 inches above the bottom up to a maximum about mid-depth, generally not greater than 2.5 feet above bottom. Maximum concentrations at Ventnor ranged up to 2.6 ppt by weight and at Nags Head were about 4.0 ppt. Median size at Ventnor ranged from 0.12 to 0.15 mm and averaged about 0.20 mm in depths of 4 feet and less at Nags Head. Results are summarized in a series of scatter plots which relate suspended sediment concentration to nozzle height, wave height, water depth and sampling distance from an observed wave-breaker-line. Results are compared to CERC laboratory data, to two excerpted concentrations from unidirectional flow tests and to the CERC TR-4 design curve of longshore wave energy versus longshore transport.

scholarly journals Laboratory data on wave propagation through vegetation with following and opposing currents

2021 ◽  
Author(s):  
Zhan Hu ◽  
Simei Lian ◽  
Huayu Wei ◽  
Yulong Li ◽  
Marcel Stive ◽  
...  
Keyword(s):  
Drag Coefficient ◽  
Wind Waves ◽  
Laboratory Data ◽  
Coastal Vegetation ◽  
Wave Dissipation ◽  
Flume Experiments ◽  
Dissipation Process ◽  
Mangrove Wetlands ◽  
Key Factor ◽  
Current Flows

Abstract. Coastal vegetation has been increasingly recognized as effective buffer against wind waves. Recent studies have advanced our understanding of wave dissipation process in vegetation (WDV). In intertidal environments, waves commonly propagate into vegetation fields with underlying tidal currents, which may alter WDV, but such influence is often overlooked. The key mechanism of WDV with co-existing currents are understudied, as previous studies have drawn contradictory conclusions on the effect of following currents on WDV. Subsequent laboratory experiments have partly explained the inconsistent conclusions, but relevant data are rarely available for theoretical or modelling development. Additionally, while the vegetation drag coefficient is a key factor influencing WDV, it is rarely reported for combined wave-current flows. This paper reports a unique dataset from two flume experiments, including 668 wave-only and wave with following/opposing current tests. A variety of data including wave height, drag coefficient, in-canopy velocity and acting force on mimic vegetation stem are recorded. This dataset is expected to assist future theoretical advancement on WDV, which may ultimately lead to more accurate prediction of wave dissipation capacity of real coastal wetlands. The dataset is available from figshare (https://doi.org/10.6084/m9.figshare.13026530.v2; Hu et al., 2020) with clear instructions for reuse. The current dataset will expand with additional WDV data from ongoing as well as planned future observation in real mangrove wetlands.

scholarly journals DIRECTIONAL SPECTRA FROM WAVE-GAGE ARRAYS

1970 ◽  
Vol 1 (12) ◽  
pp. 8 ◽  
Author(s):  
N.N. Panicker ◽  
L.E. Borgman
Keyword(s):  
Analytical Procedure ◽  
Wind Waves ◽  
Random Phase ◽  
Laboratory Data ◽  
Simulated Data ◽  
Phase Method ◽  
Directional Spectrum ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The Waves

The ocean surface may be considered to be composed of many waves traveling at different directions with different frequencies A graphical plot showing the allocation of wave energy to the different component frequencies and directions is the directional spectrum Directional spectrum has many applications in Coastal Engineering Herein an analytical procedure is developed to obtain the directional spectrum from records of an array of wave gages The two methods developed are the "locked phase method" and the "random phase method The locked phase method can be used to obtain the distribution of both phase as well as energy of the waves with respect to frequency and direction and is a deterministic approach The random phase analysis, on the other hand, is more suitable for wind waves in the ocean and yields just the distribution of energy alone as in most other procedures of spectrum analysis The procedures programmed for computers are checked using simulated data and laboratory data Wave records of the Pacific Ocean obtained off Point Mugu, California, on a 5-gage array were analyzed using the method developed and examples of the directional spectra obtained are presented.

Synthetic core from conventional logs: A new method of interpretation for identification of key reservoir properties

2015 ◽  
Vol 3 (1) ◽  
pp. SA1-SA14 ◽  
Author(s):  
Mahbub Alam ◽  
Latif Ibna-Hamid ◽  
Joan Embleton ◽  
Larry Lines
Keyword(s):  
Reservoir Simulation ◽  
Reservoir Characterization ◽  
Gamma Ray ◽  
Laboratory Data ◽  
Sedimentary Facies ◽  
Rock Properties ◽  
Reservoir Properties ◽  
Particle Volume ◽  
Single Curve ◽  
Conventional Logs

We developed a unique method to generate reservoir attributes by creating an artificial core for those wells that have no core, but that have gamma, neutron, and density logs. We examined sedimentary facies distributions, reservoir attributes, and mechanical parameters of the rock for noncored wells to increase the data density and improve the understanding of the reservoir. This method eventually helps to improve high-resolution 3D geocellular models, geomechanical models, and reservoir simulation in reservoir characterization. Artificial or synthetic cores are created using a single curve that builds facies templates using the information from the cores of nearby offset wells, which belong to the same depositional environment. The single curve, called the fine particle volume (FPV), is the average of two shale volumes calculated from the gamma-ray log and from a combination of neutron and density logs. Using facies templates, the FPV curve builds the synthetic core for geocellular modeling and reservoir simulation, and it represents the sedimentary facies distribution in the well with all the reservoir attributes obtained from laboratory data of the original core. The vertical succession of the synthetic core has the characteristics of actual sedimentary facies with reservoir attributes such as porosity, permeability, and other rock properties. The result of creating the synthetic core was validated visually and statistically with the actual cores, and each of the cored wells was considered as a noncored well. The limitation of this method is associated with the accuracy of the logging data acquisition, normalization factors, and facies template selection criteria.

scholarly journals Modeling wind waves from deep to shallow waters in Lake Michigan using unstructured SWAN

2016 ◽  
Vol 121 (6) ◽  
pp. 3836-3865 ◽  
Author(s):  
Miaohua Mao ◽  
André J. van der Westhuysen ◽  
Meng Xia ◽  
David J. Schwab ◽  
Arun Chawla
Keyword(s):  
Lake Michigan ◽  
Wind Waves ◽  
Shallow Waters

scholarly journals NUMERICAL MODELING OF OBSERVED HURRICANE WAVES

2011 ◽  
Vol 1 (32) ◽  
pp. 30 ◽  
Author(s):  
Qin Jim Chen ◽  
Kelin Hu ◽  
Andrew Kennedy
Keyword(s):  
Water Wave ◽  
Wind Waves ◽  
Field Measurements ◽  
Wave Model ◽  
Water Levels ◽  
Shallow Waters ◽  
Wind Fields ◽  
Direction Parallel ◽  
Hurricane Wind ◽  
The Right

Extensive field measurements of wind waves in deep and shallow waters during Hurricane Gustav (2008) in the Gulf of Mexico have been simulated by the spectral wave prediction model, SWAN. First, a parametric asymmetric hurricane wind model with three major improvements is used to generate hurricane wind fields for the wave model. The changes of water level near the coast are taken into account by using a storm surge model. Forced by the verified hurricane winds and hindcasted water levels, the wave model performs fairly well in comparison to the observed wave heights and periods in both deep and shallow waters except a few locations with complex bathymetry and landscape. In addition to the hurricane wind field that controls the accuracy of wave modeling in deep water, wave-surge interaction plays an important role in the wave growth and transformation in shallow water. Wave spectral comparisons show that the white-capping formulation of Westhuysen et al. (2007) generally outperforms the default formulation of Komen et al. (1984) in SWAN under hurricane conditions. The model result indicates that the asymmetry of hurricane winds and the hurricane translation result in the maximum wind waves occurring on the right side of the hurricane track and propagating in the direction parallel to the hurricane translation direction, consistent with field observations.

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