VARIABILITY OF THE SUSPENDED SEDIMENT DYNAMICS UNDER IRREGULAR WAVES

2017 ◽  
Author(s):  
Рубен Косян ◽  
Ruben Kosyan ◽  
Boris Divinsky ◽  
Boris Divinsky
Keyword(s):  
Bottom Sediment ◽  
Suspended Sediment ◽  
Frequency Distribution ◽  
Bottom Sediments ◽  
Wave Energy ◽  
Suspended Solids ◽  
Irregular Waves ◽  
Spectral Peak ◽  
Sediment Suspension ◽  
The Impact

The main objective of this paper is an analysis of the impact of the frequency distribution of wave energy on the dynamics of bottom sediment suspension as well as a study of the features of bottom sediments suspension during the passage of waves groups of varying shape and intensity. It is shown that the concentration of wave energy in the primary spectral peak promotes redistribution vertically suspended solids. Laws of suspension within the group are largely determined by the parameters of bottom roughness and the presence (absence) of ripples.

VARIABILITY OF THE SUSPENDED SEDIMENT DYNAMICS UNDER IRREGULAR WAVES

2017 ◽  
Author(s):  
Рубен Косян ◽  
Ruben Kosyan ◽  
Boris Divinsky ◽  
Boris Divinsky
Keyword(s):  
Bottom Sediment ◽  
Suspended Sediment ◽  
Frequency Distribution ◽  
Bottom Sediments ◽  
Wave Energy ◽  
Suspended Solids ◽  
Irregular Waves ◽  
Spectral Peak ◽  
Sediment Suspension ◽  
The Impact

The main objective of this paper is an analysis of the impact of the frequency distribution of wave energy on the dynamics of bottom sediment suspension as well as a study of the features of bottom sediments suspension during the passage of waves groups of varying shape and intensity. It is shown that the concentration of wave energy in the primary spectral peak promotes redistribution vertically suspended solids. Laws of suspension within the group are largely determined by the parameters of bottom roughness and the presence (absence) of ripples.

ANALYSIS OF ACCUMULATION AND DISTRIBUTION OF LEAD IN THE SYSTEM WATER-BOTTOM SEDIMENTS IN THE BACH DANG ESTUARY (VIETNAM)

2017 ◽  
pp. 62-66
Author(s):  
Truong Van Tuan ◽  
Irina Vladimirovna Volkova
Keyword(s):  
Bottom Sediment ◽  
Bottom Sediments ◽  
Water Samples ◽  
Suspended Solids ◽  
Natural Habitat ◽  
Bottom Layer ◽  
Sediment Samples ◽  
Natural Breeding ◽  
System Water ◽  
Water Bottom

Research was held in the estuary of the river Bach Dang (Dongbay community, Rakhtay district, Hai Phong, Vietnam) in June, 2012 - May, 2013. Concentration of lead was studied in water, suspended solids and bottom sediment. Clam beach (natural breeding environment of Meretrix lyrata ) was inspected regularly, every month. Water samples were taken 6 times from the bottom layer 10 cm down the bottom, once per 3 hours in each of 12 investigated zones. Bottom sediment samples were taken at the depth 2 cm. The findings show that lead accumulates mainly in suspended solids (23.3 mg/kg) and in bottom sediment (14.31 mg/kg), in water it is in small quantities (0.003 mg/kg). Analysis of bottom sediment samples taken in different places showed that they have even leadcontent, lead is distributed uniformly, localization of contaminations is not found. The results obtained can be assumed as the basis for investigating lead accumulation and its excretion by clam Meretrix lyrata organisms in the natural habitat.

scholarly journals EFFECT OF DREDGING ON HG DISTRIBUTION IN WATER AND SEDIMENTS IN THE MUCURIPE HARBOR, FORTALEZA, NE BRAZIL

2020 ◽  
Vol 52 (2) ◽  
pp. 77-84
Author(s):  
Luiz Drude De Lacerda ◽  
Ingra Kellen Belmino Belmino ◽  
Lucas Buruaem Moreira ◽  
Rozane Valente Marins
Keyword(s):  
Bottom Sediments ◽  
Suspended Solids ◽  
Progressive Increase ◽  
Coastal Sediments ◽  
Aquatic Biota ◽  
Tailings Disposal ◽  
Regional Background ◽  
Shelf Sediments ◽  
The Impact ◽  
Dredging Operation

Dredging and tailings disposal can mobilize mercury (Hg) accumulated in bottom sediments, increasing the exposure of the aquatic biota. In the Mucuripe Harbor, NE, Brazil, dredging is performed regularly, but the impact on Hg mobilization is unknown. This paper presents results from the monitoring of a dredging operation to characterize and quantify an eventual Hg mobilization. The results showed that remobilization is significant and is associated with suspended solids. Further deposition of the Hg-enriched, remobilized, suspended solids increased Hg concentrations by a factor of 1.2 and 2.0 in harbor and shelf sediments, respectively. Maximum concentrations in harbor and shelf sediments reached 79.9 ng.g-1 and 32.4 ng.g-1 (20 and 9 higher than the regional background, respectively). The progressive increase in Hg concentrations may result in higher exposure to the local biota.Keywords: metals, mobilization, contamination, coastal sediments.

scholarly journals Investigating the Impact of Power-Take-Off System Parameters and Control Law on a Rotational Wave Energy Converter’s Peak-to-Average Power Ratio Reduction

2020 ◽  
Author(s):  
H. Bora Karayaka ◽  
Yi-Hsiang Yu ◽  
Nathan Tom ◽  
Eduard Muljadi
Keyword(s):  
Wave Energy ◽  
High Speed ◽  
High Efficiency ◽  
Average Power ◽  
Gear Ratio ◽  
Irregular Waves ◽  
Strong Impact ◽  
Power Ratio ◽  
Hardware In The Loop ◽  
The Impact

Abstract Due to the irregular nature of real waves, the power captured in a wave energy converter (WEC) system is highly variable. This is an important barrier to the effective use of WECs. To address this challenge, this study focuses on a rotational WEC power-take-off system in which high-speed and high-efficiency generators along with a torque/power smoothing inertia element can be effectively utilized. In the first phase of this study, the U.S. Department of Energy’s reference model 3 (WEC-Sim RM3; two-body point absorber), along with a slider-crank WEC, were integrated for linear to rotational conversion. Relative motion between the float and spar in RM3 was the driving force for this slider-crank WEC, which is connected to a motor/generator set through a gearbox. RM3 geometry was scaled down by 25 times to work within the limits of the physical motor/generator set used in the experimentation. Once the integration in a hardware-in-the-loop simulation environment was successfully completed, data on the peak-to-average power ratio was collected for various wave conditions including regular and irregular waves. The control algorithm designed to keep the system in resonance with waves was able to maintain relatively high speed depending on the specific gear ratio and wave period. Initial results with hardware-in-the-loop simulations reveal that gear ratio and crank radius have a strong impact on the peak-to-average power ratio. In addition, it was found that output power from the generator was maximized at a larger gear ratio, as the crank radius was increased.

scholarly journals PROBLEMS OF SEDIMENTS TRANSPORT MODELING IN THE COASTAL AREA

2021 ◽  
Vol 49 (1) ◽  
pp. 93-141
Author(s):  
R. D. Kosyan ◽  
B. V. Divinsky
Keyword(s):  
Sediment Transport ◽  
Surface Waves ◽  
Wave Field ◽  
Frequency Distribution ◽  
Coastal Zone ◽  
Bottom Sediments ◽  
Wave Energy ◽  
Laboratory Experiments ◽  
Wind Waves ◽  
Wave Spectrum

Due to the development of measuring instruments, a more detailed analysis of the wave field and the field of suspended sediments spatio-temporal characteristics has become possible. Through the efforts of Russian specialists over the past decades: A unique database of observations of the sediment movement in storm situations in different physical and geographical areas of the coastal zone of the Black, Baltic, North, Mediterranean, South China Seas has been collected, supplemented by extensive data of laboratory experiments in the best laboratory in Europe (Hannover, Germany). New experimental material has been obtained to determine the physical features of sediment transport by wave flow. The main mechanisms controlling the amplitude and phase relationships of the concentration fluctuations and discharge of suspended sediment on time scales less than the period of the peak of the wind wave spectrum are considered. The presence of low-frequency fluctuations in sediment concentration with a period of the order of several periods of wind waves and an amplitude several times higher than the average value of concentration is noted. The previously unexplored problem of the wave energy frequency distribution in the spectrum of surface waves influence on the sediment transport has been analyzed. Differences in the response of the washed-out bottom to an external disturbance, represented by irregular surface waves with constant integral characteristics (significant wave height and period of the spectrum peak) and variable wave energy frequency distribution, were revealed. The influence of swell waves on the redistribution of bottom sediments in the sea coastal zone was investigated. It is shown that dividing the wave field into separate components allows a more correct description of the spatiotemporal structure of surface waves, as well as a significant refinement of the bottom sediment transport schemes in the coastal zone. Using the example of the Anapa bay bar, it is shown that situations are possible in which the alongshore flow of bottom sediments is almost completely determined by swell waves. The results of field and laboratory experiments make it possible to determine the directions for further research on the creation of physically based models of sediment transport by waves and wave currents.

APPLICATION OF ACOUSTIC METHODS IN RESEARCHES OF THE BOTTOM SEDIMENT DYNAMICS

2018 ◽  
Author(s):  
Б. Дивинский ◽  
B. Divinskiy ◽  
И. Грюне ◽  
I. Gryune ◽  
Р. Косьян ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Sediment Concentration ◽  
Irregular Waves ◽  
Single Frequency ◽  
Contactless Measurement ◽  
Measurement Means ◽  
Uniform Field ◽  
Wave Flume ◽  
Acoustic Methods ◽  
Back Scattering

Acoustic methods belong to contactless measurement means, possess high spatial and time resolution. Thus, the use of multifrequency allows directly profile both concentration and granulometric structure of the suspended substances. In 2008 in the Big Wave Flume (Hanover, Germany) by efforts of the Russian and German scientists there have been carried out the experiment on studying the bottom material suspension laws under the influence of irregular waves. The Aquascat 1000 acoustic back scattering sensor (ABS) manufactured by British company Aquatec (www.aquatecsubsea.com), equipped by a three-frequency transmitter with frequencies 1,0, 2,0 and 3,84 MHz, has been set on distance of 0,75 m from the bottom and 111 m from wave generator at the total depth of 3,2 m. Several dozen series of measurements at various parameters of surface waves have been carried out. The general picture of suspension is so that the external dynamic influence (currents, wave movements, turbulence, gravitation forces) creates a non-uniform field (gradient) of the suspended particles and in most cases due to this the average size of particles undergoes to the spatial-time variations. For this reason while defining the mass concentration of suspended sediment, using the single frequency transmitter there is necessity for numerous definition of the suspension granulometric structure what by isn’t always possible. If two and more frequencies are used the observed results comparison can give the information on average diameters of particles and on that basis the calculation of suspended sediment concentration is possibleLet's emphasize the basic advantages of back scattering acoustic gauges usage: – Obtaining the particles sizes and concentration distribution profiles is possible; – The initial granulometric structure of bottom sediments can be unknown (at use of several frequencies). The following can be referred to some lacks of the device: – The system should be calibrated in laboratory conditions; – In a positive feedback conditions the iterative computing process can converge to zero or to infinity. In this case experiments with a variation of carrier frequencies chosen for the analysis allow partially solve the problem (say experiments with different frequencies pairs, as 2/1 of MHz or 4/2 MHz).

THE IMPACT OF WIND CONDITIONS ON THE LEVELS OF TOTAL IRON CONTENT IN THE SEA OF AZOV

2017 ◽  
Author(s):  
Yuri Fedorov ◽  
Yuri Fedorov ◽  
Irina Dotsenko ◽  
Irina Dotsenko ◽  
Leonid Dmitrik ◽  
...  
Keyword(s):  
Bottom Sediments ◽  
Iron Content ◽  
Iron Concentration ◽  
Total Iron ◽  
Sea Of Azov ◽  
Open Area ◽  
The Sea Of Azov ◽  
Dissolved Iron ◽  
The Impact ◽  
Taganrog Bay

The distribution and behavior of certain of trace elements in sea water is greatly affected by both physical, chemical and hydrometeorological conditions that are showed in the scientific works of prof. Yu.A. Fedorov with coauthors (1999-2015). Due to the shallow waters last factor is one of the dominant, during the different wind situation changes significantly the dynamics of water masses and interaction in the system “water – suspended matter – bottom sediments”.Therefore, the study of the behavior of the total iron in the water of the sea at different wind situation is relevant. The content of dissolved iron forms migration in The Sea of Azov water (open area) varies from 0.017 to 0.21 mg /dm3 (mean 0.053 mg /dm3) and in Taganrog Bay from 0.035 to 0.58 mg /dm3 (mean 0.11 mg /dm3) and it is not depending on weather conditions.The reduction in the overall iron concentration in the direction of the Taganrog Bay → The Sea of Azov (open area) is observed on average more than twice. The dissolved iron content exceeding TLV levels and their frequency of occurrence in the estuary, respectively, were higher compared with The Sea of Azov (open area).There is an increase in the overall iron concentration in the water of the Azov Sea on average 1.5 times during the storm conditions, due to the destruction of the structure of the upper layer and resuspension of bottom sediments, intensifying the transition of iron compounds in the solution.

RELEASE OF NUTRIENTS FROM BOTTOM SEDIMENTS IN OSAKA BAY, JAPAN IN 2015

2017 ◽  
Author(s):  
Yukio Komai ◽  
Yukio Komai ◽  
Mana Sakata ◽  
Mana Sakata ◽  
Masaki Nakajima ◽  
...  
Keyword(s):  
Bottom Sediment ◽  
Bottom Sediments ◽  
Sea Water ◽  
Industrial Effluents ◽  
Ammonium Nitrogen ◽  
Water Release ◽  
Osaka Bay ◽  
The Core ◽  
Similar Range ◽  
Sea Area

Osaka Bay is the most polluted enclosed sea area, in which is located the eastern part of the Seto Inland Sea, Japan. There are four kinds of sources on loadings of nutrients to Osaka Bay, which are land including rivers and industrial effluents beside coast, ocean sea water, release from bottom sediment to sea water, and wet and dry deposition from air. The pollutant loadings inflowing from the land to Osaka Bay have been cut by various policies since 1970’s. The concentrations of nutrients in the inner part of Osaka Bay have showed an obvious decreasing tendency. However, the water quality in offshore sea has not satisfied the environmental standard on nutrients. We investigated the amount of nutrients released from bottom sediments. The core samples were taken at two stations in the inner part of Osaka Bay once a month from February to November, 2015. The core incubation experiment in laboratory was conducted for 24 hours according to Tada et.al. The concentrations of ammonium nitrogen (NH4-N) and phosphate phosphorus (PO4-P) were measured by an automatic analyzer. The flux showed similar range with the values investigated in 1986. The results suggested that the flux of nutrients from bottom sediments in the inner part of Osaka Bay has not decreased during summer season at least since 1985. Therefore, the contribution of release from bottom sediment on the nutrients budget would relatively become larger in inner part of Osaka Bay.

Measured and Modelled Chlorinated Contaminant Distributions in the St. Clair River Water

1986 ◽  
Vol 21 (3) ◽  
pp. 332-343 ◽  
Author(s):  
C.H. Chan ◽  
Y.L. Lau ◽  
B.G. Oliver
Keyword(s):  
River Water ◽  
Suspended Sediment ◽  
Water Samples ◽  
Concentration Distribution ◽  
Suspended Solids ◽  
Industrial Area ◽  
Concentration Profiles ◽  
Detroit River ◽  
Chemical Partitioning ◽  
Transverse Mixing

Abstract The concentration distribution of hexachlorobutadiene (HCBD), pentachloro-benzene (QCB), hexachlorobenzene (HCB) and octachlorostyrene (OCS) in water samples from transects across the upper and lower St. Clair River and the upper Detroit River were determined on four occasions in 1985. The data show a plume of these contaminants from the Sarnia industrial area. The fluxes and concentration profiles of the contaminants at Port Lambton have been modelled success fully using a simple transverse mixing model. A study on the chemical partitioning between the “dissolved” and “suspended sediment” phases shows that an important contaminant fraction is carried in the river by the suspended solids, particularly for lipophilie compounds such as HCB and OCS,

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