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Wyszukujesz frazę "sea dynamics" wg kryterium: Temat


Tytuł:
Virtual ship’s roll decay test with the use of CFD technique
Autorzy:
Krata, P.
Jachowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/243570.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
sea transport
ship stability
roll simulation
roll decay test
computational fluid dynamics
Opis:
Since safety of navigation is related to the stability performance of a ship, the transverse stability is routinely calculated and measured. One of the crucial experimental approach is a roll decay test. Although, an obtained result of the roll decay test carried out on the full-scale ship needs to be compared to a benchmark enabling an estimation of the relevant stability. Nowadays such a benchmark is just based on the simplified GM-based IMO-recommended formula. This research aims at the more sophisticated method of ship’s natural period of roll estimation and thus her stability assessment. The CFD (computational fluid dynamics) technique is applied and the result of the free roll simulation is compared to the solution of a roll equation. The one degree-of-freedom roll equation is applied with regard to the nonlinear ship righting moment and the nonlinear damping moment obtained according to Ikeda’s method. The six degrees-of-freedom simulation of ship’s roll decay test was carried out by the use of FlowVision code utilizing the Reynolds-averaged Navier–Stokes equation with regard to the turbulent flows based on the eddy viscosity concept. The semi-empirical k-ε turbulence model was applied. Thereby, the CFD-based approach allows to get rid of any assumptions regarding the value of the damping coefficient, which is an advantage over the roll equation based approach.
Źródło:
Journal of KONES; 2016, 23, 2; 215-221
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vertical distribution of zooplankton in the epipelagic zone off Sharm El-Sheikh, Red Sea, Egypt
Autorzy:
Dorgham, M.M.
Elsherbiny, M.M.
Hanafi, M.H.
Powiązania:
https://bibliotekanauki.pl/articles/48203.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
hydrography
copepod
Red Sea
Sharm El-Sheikh
Egypt
plankton
zooplankton dynamics
vertical distribution
epipelagic zone
Chaetognatha
Appendicularia
Opis:
The purpose of the present study was to track the seasonal vertical distribution of zooplankton abundance in the epipelagic zone off Sharm El-Sheikh, Red Sea. Zooplankton samples were collected seasonally within the depth ranges of 0–25, 25–50, 50–75, 75–100 m at a single station off Sharm El-Sheikh City. The present study is an attempt to expand knowledge about the structure as well as the vertical distribution of the epipelagic zooplankton community in the Gulf of Aqaba in general and in its southern part in particular. The results indicate the occurrence of 52 copepod species and several species of other planktonic groups in the study area; the zooplankton standing crop fluctuated between 1124 and 4952 organisms m−3. Copepods appeared to be the predominant component, forming an average of 86.5% of the total zooplankton count, and with other groups demonstrated a markedly different seasonal vertical distribution. Twelve bathypelagic copepod species were reported during the present study, and five species were new to the area, having migrated northwards from the main basin of the Red Sea.
Źródło:
Oceanologia; 2012, 54, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The results of integrated investigations of the Lithuanian coast of the Baltic Sea : geology, geomorphology, dynamics and human impact
Autorzy:
Bitinas, A.
Žaromskis, R.
Gulbinskas, S.
Damušyte, A.
Žilinskas, G.
Jarmalavičius, D.
Powiązania:
https://bibliotekanauki.pl/articles/2060624.pdf
Data publikacji:
2005
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Bałtyk
geologia
geomorfologia
wydma
osad denny
Baltic Sea
geology
geomorphology
dune
bottom sediments
coastal dynamics
human impact
Opis:
Integrated investigations of the Lithuanian coast of the Baltic Sea were carried out in 1999-2004 in order to satisfy an increased demand for information about the shoreline. The area of investigations included the beach and the protective dune or cliff (i.e. an onshore belt 100-300 mwide) and reached 15-20 misobaths in the offshore region. This study has resulted in the Geological Atlas of the Lithuanian coast of the Baltic Sea, which consists of digital maps including a geological-geomorphological map, a map of anthropogenic load at a scale of 1:5000 and an explanatory note. Data arrays from shoreline geodynamic monitoring and from field and analytical studies as well as descriptions of borehole sections are provided in graphic and textual annexes. On basis of these investigations 92 morpholithological profiles of the offshore zone and 101 geological cross-sections of the onshore zone were prepared. The basic geological information in the form of maps and special data arrays allows assessment of the current geological condition of the Baltic Sea shores and enables forecasts for their development. It also can be used for environmental protection and land use in the shoreline area: prevention of erosion, designing of protected, recreation and urban areas, as well as substantiation and development of a seashore monitoring system.
Źródło:
Geological Quarterly; 2005, 49, 4; 355--362
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
State equations in the mathematical model of dynamic behaviour of multihull floating unit
Autorzy:
Królicka, A.
Powiązania:
https://bibliotekanauki.pl/articles/259453.pdf
Data publikacji:
2010
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
dynamics of multihull floating unit
sea waves
stochastical processes
wave spectra
Opis:
This paper concerns dynamic behaviour of multihull floating unit of catamaran type exposed to excitations due to irregular sea waves. Dynamic analysis of multihull floating unit necessitates, in its initial stage, to determine physical model of the unit and next to assume an identified mathematical model. Correctly elaborated physical models should contain information on the basis of which a mathematical model could be built. Mathematical models describe mutual relations between crucial quantities which characterize a given system in time domain. The dynamic analysis of multihull unit was performed under assumption that the unit’s model has been linear and exposed to action of irregular sea waves. Mathematical model of such dynamic system is represented by state equations. The formulated equations take into account encounter of head wave which generates symmetrical motions of the unit, i.e. surge, heave and pitch. For solving the equations the following three wave spectra were taken into consideration: - ISSC (International Ship Structures Congress) spectrum - Pierson-Moskowitz spectrum - Paszkiewicz spectrum.
Źródło:
Polish Maritime Research; 2010, 1; 33-38
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SPH Modelling of Sea-ice Pack Dynamics
Autorzy:
Staroszczyk, R.
Powiązania:
https://bibliotekanauki.pl/articles/241351.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
sea-ice dynamics
Lagrangian description
smoothed particle hydrodynamics
moving boundary problem
Opis:
The paper is concerned with the problem of sea-ice pack motion and deformation under the action of wind and water currents. Differential equations describing the dynamics of ice, with its very distinct mateFfigrial responses in converging and diverging flows, express the mass and linear momentum balances on the horizontal plane (the free surface of the ocean). These equations are solved by the fully Lagrangian method of smoothed particle hydrodynamics (SPH). Assuming that the ice behaviour can be approximated by a non-linearly viscous rheology, the proposed SPH model has been used to simulate the evolution of a sea-ice pack driven by wind drag stresses. The results of numerical simulations illustrate the evolution of an ice pack, including variations in ice thickness and ice area fraction in space and time. The effects of different initial ice pack configurations and of different conditions assumed at the coast–ice interface are examined. In particular, the SPH model is applied to a pack flow driven by a vortex wind to demonstrate how well the Lagrangian formulation can capture large deformations and displacements of sea ice.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2017, 64, 2; 115-137
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sea-level change and projected future flooding along the Egyptian Mediterranean coast
Autorzy:
Shaltout, M.
Tonbol, K.
Omstedt, A.
Powiązania:
https://bibliotekanauki.pl/articles/48806.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
sea level
Egyptian Mediterranean coast
Nile Delta
climate change
flooding
satellite altimetry
topography
geophysical fluid dynamics
Źródło:
Oceanologia; 2015, 57, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Potential effects of abiotic factors on the abundance and distribution of the plankton in the Western Harbour, South-Eastern Mediterranean Sea, Egypt
Autorzy:
Heneash, A.M.M.
Tadrose, H.R.Z.
Hussein, M.M.A.
Hamdona, S.K.
Abdel-Aziz, N.
Gharib, S.M.
Powiązania:
https://bibliotekanauki.pl/articles/48656.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
plankton
zooplankton
distribution
Western Harbour
Mediterranean Sea
Egypt
abiotic factor
potential effect
abundance
physicochemical parameter
seasonal dynamics
Źródło:
Oceanologia; 2015, 57, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polish coastal dunes : affecting factors and morphology
Autorzy:
Łabuz, T. A.
Powiązania:
https://bibliotekanauki.pl/articles/294657.pdf
Data publikacji:
2013
Wydawca:
Stowarzyszenie Geomorfologów Polskich
Tematy:
dune coast
dune types
dune dynamics
factors impact
Polish Baltic Sea coast
Opis:
This article describe Polish coastal dunes and the factors influencing their development. The Polish coast is 500 km long and mainly exposed for a northerly direction. It is a part of the southern Baltic shore. The Polish coast is composed of mostly loose sand, till and peat. Because the coast hardiness is so weak, it is under constant threat from storm surges as well as human impact caused by rapid infrastructure development and the coastal protection measures put in place to try and protect it. These protection measures destabilize the natural coast dynamics and rebuilding process. Almost 85% of the shoreline is built up by sandy aeolian deposits and covered by different dune types. Among them are typical foredunes or inland dunes in eroded coastal areas. The second type of dune coasts are built up by land dunes, which appear on the coast as a result of sea erosion causing land regression. Sometimes dunes can be found over moraine deposits or in front of moraine old cliffs. Nowadays these habitats are heavily threatened by storm surges and human activity. In some places there is an accumulation that leads to new ridge developments. This article describes these issues with an emphasis on the present dynamics of Poland’s coastal areas.
Źródło:
Landform Analysis; 2013, 22; 33-59
1429-799X
Pojawia się w:
Landform Analysis
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parameterisation of a population model for Acartia spp. in the Southern Baltic Sea. Part 1. Development time
Autorzy:
Dzierzbicka-Glowacka, L.
Lemieszek, A.
Zmijewska, M.I.
Powiązania:
https://bibliotekanauki.pl/articles/49034.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
population dynamics
environment condition
Baltic Sea
development
Acartia bifilosa
Acartia
growth
Gdansk Gulf
population model
Opis:
The copepod model (see Dzierzbicka-Głowacka 2005b),red uced to a zero-dimensional population model (Fennel 2001,S tegert et al. 2007),i s calibrated for Acartia spp. under the environmental conditions typical of the southern Baltic Sea. Most of the coefficients used in the model are taken from the literature,co ntaining values from various published studies and parameters derived for similar species. The parameters for growth are presented in Part 1; those for population dynamics are given in Part 2. Ingestion rates,whic h are dependent on developmental stage, food supply,temp erature and weight of the animals, are estimated for Acartia bifilosa at 15◦C from the Gdańsk Deep after the experimental data of Ciszewski & Witek (1977). In Part 1 the model presents the change in mean individual mass in successive stages. Quantitative formulae are obtained describing the effects of temperature and food concentration on the development time of Acartia spp. for each of the model stage groups. The generation time during the seasons in the upper layer of the Gdańsk Deep is also determined. The simulations computed here are similar to the experimental results. Part 2 (Dzierzbicka-Głowacka et al. 2009 – this issue) will evaluate egg production as a function of the above-mentioned parameters,temp erature and food availability.
Źródło:
Oceanologia; 2009, 51, 2; 165-184
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling the seasonal dynamics of marine plankton in the Southern Baltic Sea. Part 2. Numerical simulations
Autorzy:
Dzierzbicka-Glowacka, L.
Powiązania:
https://bibliotekanauki.pl/articles/48617.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
turbulence
nutrient
Clupea harengus
encounter rate
marine plankton
Baltic Sea
microzooplankton
phytoplankton
modelling
Pseudocalanus elongatus
seasonal dynamics
Opis:
This work presents numerical simulations of the time-dependent vertical distributions of phytoplankton, microzooplankton, Pseudocalanus elongatus, early juvenile herring (Clupea harengus) and two nutrient components (total inorganic nitrogen and phosphate) using the 1D-Coupled EcosystemMo del with a highresolution mesozooplankton (herbivorous copepods) module for P.elongatus and a simple prey-predator model for early juvenile herring C. harengus. This m odel was discussed in detail in Part 1. The calculations were done for one year (1999) for a station in the Gdańsk Deep (southern Baltic Sea). The results of the simulations were compared with the mean concentrations of nutrients, phytoplankton and zooplankton recorded in situ. The differences between the calculated and mean recorded values of nutrients and phytoplankton are c. 5–30% and depend on the month and depth for which the calculations were done. However, the calculated depth-integrated biomass of P. elongatus differs fromthe mean recorded value. This difference ranges from30 to 50% at the end of May. The 1DCEM model can be used to forecast ecological changes in the southern Baltic Sea.
Źródło:
Oceanologia; 2006, 48, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Long term variation of sardine Sardina pilchardus spawning along the Atlantic coast of Northwest Africa (21–26°N): characterization and spatiotemporal variability in spawning habitat
Autorzy:
Abdelouahab, H.
Berraho, A.
Baibai, T.
Larissi, J.
Charib, S.
Agouzouk, A.
Makaoui, A.
Ettahiri, O.
Errhif, A.
Powiązania:
https://bibliotekanauki.pl/articles/2079005.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
pelagic fish
sardine
Sardina pilchardus
population dynamics
environment change
spawning
sea surface
temperature
Atlantic coast
Opis:
Small pelagic fish such as sardine show strong recruitment variability often associated with environmental changes influencing the spawning process and ultimately, affecting population dynamics. Sardine (Sardina pilchardus, Walbaum 1792) is one of the most exploited pelagic species along the northwest African coast. The main spawning occurs during the cold season (autumn—winter). A time-series autumn—winter surveys extending from 1994 to 2015 sampled sardine eggs, along the southern area of the Moroccan Atlantic coast (26°N—21°N) were analyzed. The present work focuses on examining the inter-annual variability of the spawning habitat by analyzing the spatial-temporal variability of sardine egg distribution and density extracted from the data collected over the period 1994—2015. Generalized additive models (GAM) were used to detect the relationships between the sardine distribution, expressed as egg density and the presence or absence data and relevant hydrobiological environmental variables, such as salinity, temperature and zooplankton biomass. The generalized additive models showed significant relationships between the environment variables (SST, SSS and Zooplankton biomass) and sardine density, but not with sardine presence. Given that the study area is characterized by high mesoscale features and significant upwelling activities, the variability of upwelling processes could explain the changes of spawning ground position and thermal window
Źródło:
Oceanologia; 2021, 63, 1; 1-11
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Life in sympatry: coexistence of native Eurytemora affinis and invasive Eurytemora carolleeae in the Gulf of Finland (Baltic Sea)
Autorzy:
Sukhikh, N.
Souissi, A.
Souissi, S.
Holl, A.-C.
Schizas, N.V.
Alekseev, V.
Powiązania:
https://bibliotekanauki.pl/articles/48676.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Eurytemora affinis
Eurytemora carolleeae
Copepoda
zooplankton
invasive species
native species
population dynamics
Finland Gulf
Baltic Sea
Źródło:
Oceanologia; 2019, 61, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Information about dynamics of the sea surface as a means to improve safety of the unmanned vessel at sea
Autorzy:
Przyborski, M.
Powiązania:
https://bibliotekanauki.pl/articles/259934.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
hypothesis testing
nonlinearity
sea dynamics
USV
Opis:
One of the fundamental states of the sea surface is its heave. Despite of years of the intense scientific inquiry, no clear understanding of the influence of this aspect on the dynamics of the sea environment has emerged. The separation of two nearby fluid elements which one may observed for example as a free floating of small objects on the sea surface (rescuers on the rough sea or small research vessels) is caused by the interaction of different components. On the other hand one may say that the heave of the sea is also a summary interaction of a few components describing the dynamics of the sea. Therefore it is the most important aspect, which influenced the dispersion phenomenon. This observation has important consequences for many different problems as for example conducting Search and Rescue missions and using unmanned ships. We would like to present results of our experiment focused on finding the answer to question about nature of the heave of the sea and its influence on safety of Unmanned Surface Vessels (USV).
Źródło:
Polish Maritime Research; 2016, 4; 3-7
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł

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