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Wyszukujesz frazę "hydrodynamic condition" wg kryterium: Temat


Wyświetlanie 1-9 z 9
Tytuł:
Modelling longshore sediment transport under asymmetric waves
Autorzy:
Ostrowski, R.
Szmytkiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/49027.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
coastal zone
hydrodynamic condition
sandy sediment
wave-current interaction
sediment transport
wave asymmetry
Opis:
Two wave theories are applied in calculations of longshore sediment transport rates: the second Stokes approximation and the cnoidal theory. These approaches are used to model sand motion in nearshore locations beyond and within the surf zone. Wave-current interaction in the nearbed layer and bed shear stresses are solved using a momentum integral method, whereas sediment transport is described by a three-layer model encompassing bedload, contact load and suspended load. Computational results for asymmetric waves are compared with the results obtained using linear wave theory and the conventional sediment transport models of Bailard (1981), Bijker (1971) and Van Rijn (1993).
Źródło:
Oceanologia; 2006, 48, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of the sandy coast: Hydrodynamic and morphodynamic conditions (on the example of the Eastern Gulf of Finland)
Autorzy:
Divinsky, B.V.
Ryabchuk, D.V.
Kosyan, R.D.
Sergeev, A.Y.
Powiązania:
https://bibliotekanauki.pl/articles/2078924.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
sandy coast
coastal zone
climate change
hydrodynamic condition
morphodynamic condition
sea level
surface wave
sediment transport
numerical modelling
Finland Gulf
Opis:
Forecasting the coastal zone development under possible climatic changes and technogenic impact is an extremely important task. This forecasting is based on our understanding of the mechanism of the hydrodynamic processes impact on the coastal zone. The goal of this work is to describe the hydrodynamic conditions (currents, sea level, surface waves) of coastal waters and to assess the influence of hydrodynamic parameters on the general dynamics of the beach. The object of this study is a part of the southern coastal zone of the Gulf of Finland (Baltic Sea). The method of research is a full-scale experiment and mathematical modeling. The initial data for the analysis are climatic characteristics of the hydrodynamic regime of the sea (velocity and direction of currents, sea level, integral parameters of wind seas and swell), as well as interannual variations in the position of the coastline in the region of the Izhora village in the eastern part of the Gulf of Finland. Interannual variations in hydrodynamic parameters and volumes of bottom material transported under the influence of wind seas and swell were estimated. Main conclusion: swell waves determine the general background in the patterns of the bottom material transport, and the contribution of wind seas is in the formation of beach properties, namely, the accumulation or decrease of beach material
Źródło:
Oceanologia; 2021, 63, 2; 214-226
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Waves, currents and sea level variations along the Letipea - Sillamäe coastal section of the Southern Gulf of Finland
Autorzy:
Suursaar, U.
Powiązania:
https://bibliotekanauki.pl/articles/48913.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
wave
variation
hydrodynamic condition
measurement
Doppler current prolifer
calibration
semi-empirical hindcast
water parameter
upwelling
coastal jet
climate change
Baltic Sea
Letipea-Sillamae coastal section
Finland Gulf
Opis:
Variations in the hydrodynamic conditions were studied on the basis of 336 days of measurements with a Doppler current profiler. With wave data as a calibration reference, a semi-empirical hindcast of wave parameters is presented in the fetch- limited near-shore area for the period 1966–2008. A resultant 4–6 cm s−1 westward current dominated along the coast. Occasional fast sub-surface westward currents under modest wind forcing, as well as asymmetrical vertical profiles for westward and eastward currents indicated the influence of upwelling-related baroclinic coastal jets. The average frequency of upwelling was estimated at 17%; some of the events were identified in near-homothermic winter conditions on the basis of salinity and multi-layer flow records. While the mean sea level trend at Narva-Jõesuu roughly approximated the global estimates for 1899–2009, the annual maximum sea level increase was 5–8 mm yr−1. Both mean and maximum wave heights declined as a result of decreasing winds from the north.
Źródło:
Oceanologia; 2010, 52, 3; 391-416
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of the Svalbard fjord Hornsund
Autorzy:
Jakacki, J.
Przyborska, A.
Kosecki, S.
Sundfjord, A.
Albretsen, J.
Powiązania:
https://bibliotekanauki.pl/articles/48674.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
hydrodynamic model
regional variability
oceanographic condition
salt content
heat content
anomaly
Hornsund Region
Svalbard Fjord
Opis:
The Arctic Ocean is currently in transition towards a new, warmer state. Understanding the regional variability of oceanographic conditions is important, since they have a direct impact on local ecosystems. This work discusses the implementation of a hydrodynamic model for Hornsund, the southernmost fjord of western Svalbard. Despite its location, Hornsund has a stronger Arctic signature than other Svalbard fjords. The model was validated against available data, and the seasonal mean circulation was obtained from numerical simulations. Two main general circulation regimes have been detected in the fjord. The winter circulation represents a typical closed fjord system, while in summer the fresh water discharge from the catchment area generates a surface layer with a net flow out of Hornsund. Also described are the local hydrographic front and its seasonal variability, as well as the heat and salt content in Hornsund. The integration of salt and heat anomalies provides additional information about the salt flux into the innermost basin of the fjord - Brepollen during the summer. Extensive in situ observations have been collected in Hornsund for the last two decades but our hydrodynamic model is the first ever implemented for this area. While at the moment in situ observations better represent the state of this fjord's environment and the location of measurements, a numerical model, despite its flaws, can provide a more comprehensive image of the entire fjord's physical state. In situ observations and numerical simulations should therefore be regarded as complementary tools, with models enabling a better interpretation and understanding of experimental data.
Źródło:
Oceanologia; 2017, 59, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The analysis of oil balance in crank bearing
Analiza bilansu oleju w lozysku korbowym
Autorzy:
Kyureghyan, K.
Piekarski, W.
Powiązania:
https://bibliotekanauki.pl/articles/792740.pdf
Data publikacji:
2012
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
hydrodynamic lubrication
cross slide bearing
Reynolds equation
crank bearing
oil balance
slide bearing
technical condition
engine
analysis
Źródło:
Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2012, 12, 2
1641-7739
Pojawia się w:
Teka Komisji Motoryzacji i Energetyki Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical oceanographic conditions and a sensitivity study on meltwater runoff in a West Greenland fjord: Kangerlussuaq
Autorzy:
Monteban, D.
Pedersen, J.O.P.
Nielsen, M.H.
Powiązania:
https://bibliotekanauki.pl/articles/2079080.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
melt water
hydrodynamic model
numerical model
seasonal variability
physical condition
water mass
Arctic fjord
West Greenland
Kangerlussuaq
Opis:
In this paper, we discuss the first setup of a hydrodynamic model for the fjord-type estuary Kangerlussuaq, located in West Greenland. Having such a high-fidelity numerical model is important because it allows us to fill in the temporal and spatial gaps left by in situ data and it allows us to examine the response of the fjord to changes in ice sheet runoff. The numerical model is calibrated against in situ data, and a one-year simulation was performed to study the seasonal variability in the physical oceanographic environment and the fjord's response to changing meltwater runoff. The fjord consists of two distinct parts: a deep inner part that is 80 km long with weak currents and a shallow part that covers the outer 100 km of the fjord connected to the ocean. The outer part has very fast currents (∼1.3 m/s), which we suggest prevents winter sea ice formation. The dominant currents in the fjord are oriented parallel to the long axis of the fjord and are driven by tides and (during summer) freshwater inflow from meltwater-fed rivers. Furthermore, mixing processes are characterized by strong tidal mixing and bathymetric restrictions, and the deep-lying water mass is subject to renewal primarily in wintertime and is almost dynamically decoupled from the open ocean during summertime. Finally, a sensitivity study on the changing meltwater runoff was performed, showing that increasing freshwater runoff considerably strengthens stratification in the upper 100 m of the water column in the inner part of the fjord.
Źródło:
Oceanologia; 2020, 62, 4PA; 460-477
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relationships between coastal processes and properties of the nearshore sea bed dynamic layer
Autorzy:
Ostrowski, R.
Pruszak, Z.
Powiązania:
https://bibliotekanauki.pl/articles/47468.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Baltic coast
Baltic dune
cliff
coastal process
coastal zone
geomorphological condition
hydrodynamic impact
Polska
sandy sediment
sediment transport
Opis:
The paper discusses the notion of a layer of sandy sediments overlying a substratum of cohesive deposits in the coastal zone. This layer of sand is generally more mobile and is therefore conventionally referred to as the dynamic layer. Its parameters are important to coastal lithodynamic and morphodynamic processes caused by waves and currents. On the other hand, the dynamic layer is formed by nearshore hydrodynamic impact. The variability of the features of the dynamic layer on the southern Baltic dune and cliff shores in Poland is analysed on the basis of selected geological data supported by local seismo-acoustic field investigations. It appears that the conventional notion of the dynamic layer makes sense only in specific geomorphologic conditions. In such cases, mostly related to cliff shores, theoretical modelling of sediment transport should take the properties of the dynamic layer into account.
Źródło:
Oceanologia; 2011, 53, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A quasi phase-resolving model of net sand transport and short-term cross-shore profile evolution
Autorzy:
Ostrowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/48565.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
coastal zone
hydrodynamics
wave-current condition
cross-shore profile
Baltic Sea
evolution
modelling
sand transport
sediment transport
hydrodynamic impact
Opis:
A way of modelling of the net sediment transport rate on a cross-shore profile and the resulting sea bed changes is presented. In the sediment transport computations, a three-layer model with a description of the bedload based on the water-soil mixture theory by Kaczmarek& Ostrowski (1998, 2002) is used. The modelling system is applied to wave-current conditions variable over the cross-shore profile, and determined using the computational frameworkof Szmytkiewicz (2002a, b). The sediment transport module incorporates the asymmetric wave approaches as proposed by Ostrowski (2002). Model simulations have been produced for uniformly sloped and multi-bar initial cross-shore profiles. Some of the model results are compared with the IBW PAN (Institute of Hydroengineering of the Polish Academy of Sciences) field data collected at the Coastal Research Station in Lubiatowo.
Źródło:
Oceanologia; 2003, 45, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Currents and waves in the Northern Gulf of Riga: measurement and long-term hindcast
Autorzy:
Suursaar, U.
Kullas, T.
Aps, R.
Powiązania:
https://bibliotekanauki.pl/articles/47862.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
hydrodynamic modelling
water exchange
wave
Riga Gulf
Baltic Sea
long-term hindcast
wave measurement
wind force
wind condition
atmospheric circulation
Opis:
Based on measurements of waves and currents obtained for a period of 302 days with a bottom-mounted RDCP (Recording Doppler Current Profiler) at two differently exposed locations, a model for significant wave height was calibrated separately for those locations; in addition, the Gulf of Riga-Vainameri 2D model was validated, and the hydrodynamic conditions were studied. Using wind forcing data from the Kihnu meteorological station, a set of current, water exchange and wave hindcasts were obtained for the period 1966–2011. Current patterns in the Gulf and in the straits were wind-dependent with characteristic wind switch directions. The Matsi coast was prone to upwelling in persistent northerly wind conditions. During the hindcast period, currents increased along the Koiguste coast and in the Suur Strait, waves decreased noticeably off Koiguste but fluctuated without a clear linear trend near Matsi. The spatially contrasting results for differently exposed coasts were related to the corresponding variations in local wind conditions and to changes in atmospheric circulation patterns over northern Europe.
Źródło:
Oceanologia; 2012, 54, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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