scholarly journals RESEARCHES ON DOUBLE CURTAIN WALL BREAKWATER

1966 ◽  
Vol 1 (10) ◽  
pp. 51
Author(s):  
Shigeru Tanaka
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
High Speed ◽  
Wave Length ◽  
High Tide ◽  
North Coast ◽  
Curtain Wall ◽  
Remarkable Effect ◽  
The North ◽  
Sea Bottom

It has been clarified by some researchers(R. L. Wiegel1 , F. Ursell", R. Morihira & S. Anezaki3), etc.) that the single curtain wall breakwater has no good wave-dissipating effect at the usual coastal area where the ratio of water-depth to wave-length is considerably small. The author has made researches concerning "Multiple Curtain Wall Breakwater", anticipating the supposition that it may be very effective for the dissipation of wave energy even at a shallow coastal zone, because of its peculiar effectiveness upon wave dissipation. Double curtain wall breakwater is composed of two parallel rows of curtain walls attached to the supporting props installed at an adequate interval. The interval of the said two rows is very important, and the determination of a proper interval, relating to a high wind wave having a definite length and a definite wave height, is one of the main objects of this research. These researches were mainly made experimentally. At first the author assumed that the design wave had the period of 5-6 sec, the length of 50 - 60 m and the height of 1.5 m. The results of the model experiment show that the double curtain wall breakwater, installed at the depth ranging 3 - 10 m, has remarkable effect on wave dissipation.Secondly the author selected a particular location on the north coast of Osaka Bay where the design wave has the period of 7 - 9 sec, the wave length of 65 - 70 m and the wave height of 3.8 - 4.0 m at offshore. At the expected site of thebreakwater, the sea bottom is flat and nearly horizontal, and the water depth under the condition of the extraordinary high tide is 10.5 m above the sea bottom, and an experiment was carried out by the model for this location. One kind of model was constructed in a shallow basin of 0.5 m x 25 m x 30 m, in the scale of 1 to 40 and of 1 to 70, in order to determine its transmission coefficient of wave height. Another kind of model was made in a glazed steel frame tank of 1.6 mx 1.8 m x 28 m, equipped with a piston type wave generator operated by 5 HP motor. The scale of this model is 1 to 10, and its purpose is to secure the surface disturbance and to trace the trajectories of small suspended particles by a 16 mm cine camera and a high speed motion camera.

scholarly journals THE SOLITARY WAVE: ITS CELERITY, PROFILE, INTERNAL VELOCITIES AND AMPLITUDE ATTENUATION IN A HORIZONTAL SMOOTH CHANNEL

2000 ◽  
Vol 1 (3) ◽  
pp. 2 ◽  
Author(s):  
James W. Daily ◽  
Samuel C. Stephan, Jr.
Keyword(s):  
Solitary Wave ◽  
Wave Height ◽  
Water Depth ◽  
Wave Length ◽  
Horizontal Displacement ◽  
Smooth Channel ◽  
Amplitude Attenuation ◽  
Oscillatory Waves

The solitary wave consists of a single elevation of water above the originally undisturbed level as shown in Figure 1. It is translatory, a passing wave causing a definite net horizontal displacement of the liquid. While the characteristics of oscillatory waves depend on wave length as well as wave height and water depth, the solitary wave is apparently described completely by the wave height and water depth so long as attenuation due to friction is unimportant.

scholarly journals Mapping Impact of Tidal Flooding on Solar Salt Farming in Northern Java using a Hydrodynamic Model

2019 ◽  
Vol 8 (10) ◽  
pp. 451 ◽  
Author(s):  
Nirwansyah ◽  
Braun
Keyword(s):  
High Tide ◽  
Water Levels ◽  
North Coast ◽  
Flood Events ◽  
Accurate Identification ◽  
Solar Salt ◽  
Salt Production ◽  
The North ◽  
Production Area ◽  
The Impact

The number of tidal flood events has been increasing in Indonesia in the last decade, especially along the north coast of Java. Hydrodynamic models in combination with Geographic Information System applications are used to assess the impact of high tide events upon the salt production in Cirebon, West Java. Two major flood events in June 2016 and May 2018 were selected for the simulation within inputs of tidal height records, national seamless digital elevation dataset of Indonesia (DEMNAS), Indonesian gridded national bathymetry (BATNAS), and wind data from OGIMET. We used a finite method on MIKE 21 to determine peak water levels, and validation for the velocity component using TPXO9 and Tidal Model Driver (TMD). The benchmark of the inundation is taken from the maximum water level of the simulation. This study utilized ArcGIS for the spatial analysis of tidal flood distribution upon solar salt production area, particularly where the tides are dominated by local factors. The results indicated that during the peak events in June 2016 and May 2018, about 83% to 84% of salt ponds were being inundated, respectively. The accurate identification of flooded areas also provided valuable information for tidal flood assessment of marginal agriculture in data-scarce region.

scholarly journals DEFORMATION UP TO BREAKING OF PERIODIC WAVES ON A BEACH

1976 ◽  
Vol 1 (15) ◽  
pp. 26 ◽  
Author(s):  
Ib A. Svendson ◽  
J. Buhr Hansen
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Wave Length ◽  
Empirical Relation ◽  
Breaking Point ◽  
Periodic Waves ◽  
Depth Ratio ◽  
Surface Profiles ◽  
Deep Water Wave ◽  
Sloping Beach

An experimental description is presented for 'the transformation of periodic waves which approach breaking on a gently sloping beach. The data include the variation of wave height, phase velocity, wave surface profiles, and the maximum value of the wave height to water depth ratio (H/h)max around the breaking point. The results are compared with the theories of sinusoidal and cnoidal wave shoaling, and the latter is shown in most cases to agree remarkably well when the laminar energy loss along the walls and bottom of the wave tank is included. An empirical relation is established between wave length to water depth ratio L/h at the breaking point and the deep water wave steepness H0/L0. Also the maximum wave height to water depth ratio at breaking shows considerably less scattering than found previously, when plotted versus S = hx L/h, hx being bottom slope.

scholarly journals EXPERIMENTAL INVESTIGATIONS OF PERIODIC WAVES NEAR BREAKING

1980 ◽  
Vol 1 (17) ◽  
pp. 14 ◽  
Author(s):  
J. Buhr Hansen
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Wave Length ◽  
Experimental Investigations ◽  
Periodic Waves ◽  
Wave Energy Flux ◽  
Surface Profiles ◽  
Series Of Experiments ◽  
Sloping Beach ◽  
Theory And Experiments

The results presented are from a series of experiments of periodic waves approaching breaking on a gently sloping beach. The recorded surface profiles are compared with a cnoidal theory taking into account the effect of the bottom slope. In both theory and experiments a skewness of the profile is observed. A fair agreement is found within certain limits of the wave height to water depth ratio and when the slope is sufficiently gentle. The change in water depth over a wave length must be sufficiently small. The detailed analysis of the surface profiles including the skewness element shows good agreement with the cnoidal theory in cases where the wave height variation is as predicted by cnoidal wave shoaling. The recorded surface profiles together with the recorded phase velocities are further used in computing the wave energy flux based on the theoretical relations from linear and cnoidal theories. Reasonable constancy is observed over the whole length covered by the experiments. Finally the recorded wave set-down is compared with the results of linear and cnoidal theories. When approaching breaking neither of the theories can apparently predict the recorded water level changes.

scholarly journals North Sea Infragravity Wave Observations

2021 ◽  
Vol 9 (2) ◽  
pp. 141
Author(s):  
Ad J.H.M. Reniers ◽  
Remy Naporowski ◽  
Marion F. S. Tissier ◽  
Matthieu A. de Schipper ◽  
Gal Akrish ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Wave Height ◽  
North Sea ◽  
Water Depth ◽  
Local Equilibrium ◽  
Potential Contribution ◽  
Wave Forcing ◽  
Dutch Coast ◽  
The North ◽  
Wave Heights

Coastal safety assessments with wave-resolving storm impact models require a proper offshore description for the incoming infragravity (IG) waves. This boundary condition is generally obtained by assuming a local equilibrium between the directionally-spread incident sea-swell wave forcing and the bound IG waves. The contribution of the free incident IG waves is thus ignored. Here, in-situ observations of IG waves with wave periods between 100 s and 200 s at three measurement stations in the North Sea in water depths of O(30) m are analyzed to explore the potential contribution of the free and bound IG waves to the total IG wave height for the period from 2010 to 2018. The bound IG wave height is computed with the equilibrium theory of Hasselmann using the measured frequency-directional sea-swell spectra as input. The largest IG waves are observed in the open sea with a maximum significant IG wave height of O(0.3) m at 32 m water depth during storm Xaver (December 2013) with a concurrent significant sea-swell wave height in excess of 9 m. Along the northern part of the Dutch coast, this maximum has reduced to O(0.2) m at a water depth of 28 m with a significant sea-swell wave height of 7 m and to O(0.1) m at the most southern location at a water depth of 34 m with a significant sea-swell wave height of 5 m. These appreciable IG wave heights in O(30) m water depth represent a lower bound for the expected maximum IG wave heights given the fact that in the present analysis only a fraction of the full IG frequency range is considered. Comparisons with the predicted bound IG waves show that these can contribute substantially to the observed total IG wave height during storm conditions. The ratio between the predicted bound- and observed total IG variance ranges from 10% to 100% depending on the location of the observations and the timing during the storm. The ratio is typically high at the peak of the storm and is lower at both the onset and waning of the storm. There is significant spatial variability in this ratio between the stations. It is shown that differences in the directional spreading can play a significant role in this. Furthermore, the observed variability along the Dutch coast, with a substantially decreased contribution of the bound IG waves in the south compared to the northern part of the Dutch coast, are shown to be partly related to changes in the mean sea-swell wave period. For the southern part of the Dutch coast this corresponds to an increased difference with the typically assumed equilibrium boundary condition although it is not clear how much of the free IG-energy is onshore directed barring more sophisticated observations and/or modeling.

scholarly journals ON A SEQUENTIAL BEHAVIOUR OF SEA-STATES

1984 ◽  
Vol 1 (19) ◽  
pp. 41
Author(s):  
A. Sanchez-Arcilla
Keyword(s):  
Wave Height ◽  
Large Volume ◽  
Significant Wave Height ◽  
Average Duration ◽  
Probability Distributions ◽  
North Coast ◽  
Stationary Processes ◽  
Significant Wave ◽  
The North ◽  
Sequential Behaviour

Probability distributions theoretically derived for gaussian, stationary processes are applied here to the sequential behaviour of sea-states. This behaviour defined by the curve of evolution of significant wave-height, Hs(t), is characterized by variables such as: intensity of storm peaks,time between beginnings of storms, average duration of calms and storms, average number of consecutive storms, expected value of the extremal storm peak, etc. The distributions obtained for these variables heve been tested with 5 years of wave data, recorded in the north coast of Spain. The agreement obtained is satisfactory in most cases, showing the validity of the approach and its applicability to situations in which only a limited amount of data is available. However, in cases where a large volume of data exists, empirically selected distributions could provide a marginally better fit.

MBAH HENDRO KUSUMO BIN SYECH AHMAD MUTAMAKKIN: JEJAK SYIAR ISLAM DI WILAYAH PATI

EMPIRISMA ◽  
2008 ◽  
Vol 27 (2) ◽  
Author(s):  
Fathimatuz Zahra Dan Abdul Azis
Keyword(s):  
Central Region ◽  
Marital Relationship ◽  
Southern Region ◽  
North Coast ◽  
The North ◽  
Trace Back ◽  
Northern Regions ◽  
The One

Pati is a region on the north coast, according to the hypothesis of the researcher, the region is divided into three categories. The northern regions are more religious, the central is more plural, while the southern region is in the middle. In the central region there are many relics of tombs believed to be the those of the Muslim proselytizers in the area of Pati. The one that attracts the researcher is a tomb in the Gambiran area, where there are five local Muslim saints buried, one of them belons to mbah Hendro Kusumo, the son of Syech Ahmad Mutamakkin. This article attempts to trace back the spreading of Islam in Pati based on the existence of thetomb of Mbah Hendro Kusumo. It wants to answer question of whethere the existence of his tomb is due to his studying there or marital relationship, and how it relates to the spreading of Islam.Keywords: Mbah Hendro Kusumo, Traces of Islamic Dakwah, Islam

4 The Tyara Site

1968 ◽  
Vol 22 ◽  
pp. 44-79 ◽  
Author(s):  
William E. Taylor
Keyword(s):  
Sandy Beach ◽  
North Coast ◽  
National Museum ◽  
The West ◽  
Rock Outcrops ◽  
Small Boat ◽  
The North

The Tyara site, KkFb-7 in the National Museum catalogue and site file, faces the north coast of the Ungava mainland and rests on the west shore of Sugluk Island (Fig. 1). That island stands about five hundred yards from the mainland and from Sugluk Inlet, one of the few good harbors on that coast. This handsome little island, about one and one-half miles long and as wide, consists of rounded, rugged, hardrock hills that shelter well-vegetated, generally flat-floored valleys. The valleys often contain marshy patches. The shore, of variable incline, is quite jagged, a result of abrupt rock outcrops projecting seaward from brief stretches of sandy beach. The shore facing the mainland is, therefore, quite convenient for small boat use. Dark grey gneisses seem to predominate, although they are often cut by dykes and veins of lighter material, notably quartz. The dense, green valley and hillside vegetation includes willows, mosses, grasses, lichens, and a pleasant profusion of arctic wild flowers (Polunin 1948, Pt. III). I was told at Sugluk that at the head of the inlet, willows, growing in protected situations, reach the thickness of a man's wrist.

Seed production and seedling emergence of Giant Parramatta grass on the north coast of New South Wales

1996 ◽  
Vol 36 (3) ◽  
pp. 299 ◽  
Author(s):  
TS Andrews ◽  
RDB Whalley ◽  
CE Jones
Keyword(s):  
Seed Production ◽  
Seed Bank ◽  
New South ◽  
New South Wales ◽  
Seed Banks ◽  
North Coast ◽  
The North ◽  
South Wales ◽  
Seed Fall ◽  
The Impact

Inputs and losses from Giant Parramatta grass [GPG, Sporobolus indicus (L.) R. Br. var. major (Buse) Baaijens] soil seed banks were quantified on the North Coast of New South Wales. Monthly potential seed production and actual seed fall was estimated at Valla during 1991-92. Total potential production was >668 000 seeds/m2 for the season, while seed fall was >146000 seeds/m2. Seed fall >10000 seeds/m2.month was recorded from January until May, with further seed falls recorded in June and July. The impact of seed production on seed banks was assessed by estimating seed banks in the seed production quadrats before and after seed fall. Seed banks in 4 of the 6 sites decreased in year 2, although seed numbers at 1 damp site increased markedly. Defoliation from mid-December until February, April or June prevented seed production, reducing seed banks by 34% over 7 months. Seed banks in undefoliated plots increased by 3300 seeds/m2, although seed fall was estimated at >114 000 seeds/m2. Emergence of GPG seedlings from artificially established and naturally occurring, persistent seed banks was recorded for 3 years from bare and vegetated treatment plots. Sown seeds showed high levels of innate dormancy and only 4% of seeds emerged when sown immediately after collection. Longer storage of seeds after collection resulted in more seedlings emerging. Estimates of persistent seed banks ranged from 1650 to about 21260 seeds/m2. Most seedlings emerged in spring or autumn and this was correlated with rainfall but not with ambient temperatures. Rates of seed bank decline in both bare and vegetated treatment plots was estimated by fitting exponential decay curves to seed bank estimates. Assuming no further seed inputs, it was estimated that it would take about 3 and 5 years, respectively, for seed banks to decline to 150 seeds/m2 in bare and vegetated treatments.

scholarly journals The Potential of GRASP/GARRLiC Retrievals for Dust Aerosol Model Evaluation: Case Study during the PreTECT Campaign

2021 ◽  
Vol 13 (5) ◽  
pp. 873
Author(s):  
Dimitra Konsta ◽  
Alexandra Tsekeri ◽  
Stavros Solomos ◽  
Nikolaos Siomos ◽  
Anna Gialitaki ◽  
...  
Keyword(s):  
Model Evaluation ◽  
Dust Concentration ◽  
Saharan Dust ◽  
North Coast ◽  
Concentration Profiles ◽  
Future Studies ◽  
Aerosol Model ◽  
The North ◽  
Sun Photometer

We use the Generalized Retrieval of Aerosol Surface Properties algorithm (GRASP) to compare with dust concentration profiles derived from the NMME-DREAM model for a specific dust episode. The GRASP algorithm provides the possibility of deriving columnar and vertically-resolved aerosol properties from a combination of lidar and sun-photometer observations. Herein, we apply GRASP for analysis of a Saharan dust outburst observed during the “PREparatory: does dust TriboElectrification affect our ClimaTe” campaign (PreTECT) that took place at the North coast of Crete, at the Finokalia ACTRIS station. GRASP provides column-averaged and vertically resolved microphysical and optical properties of the particles. The retrieved dust concentration profiles are compared with modeled concentration profiles derived from the NMME-DREAM dust model. To strengthen the results, we use dust concentration profiles from the POlarization-LIdar PHOtometer Networking method (POLIPHON). A strong underestimation of the maximum dust concentration is observed from the NMME-DREAM model. The reported differences between the retrievals and the model indicate a high potential of the GRASP algorithm for future studies of dust model evaluation.

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