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Wyszukujesz frazę "wind shear" wg kryterium: Temat


Wyświetlanie 1-6 z 6
Tytuł:
Flow, waves and water exchange in the Suur Strait, Gulf of Riga, in 2008
Autorzy:
Raudsepp, U.
Laanemets, J.
Haran, G.
Alari, V.
Pavelson, J.
Kouts, T.
Powiązania:
https://bibliotekanauki.pl/articles/49038.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
flow
wave
water exchange
Suur Strait
Riga Gulf
modelling
shear velocity
Baltic Sea
wind
wind condition
storm
wave heigh
sediment
seasonal cycle
horizontal distribution
outflow
Opis:
Wind, flow and wave measurements were performed in November–December in 2008 in the relatively narrow and shallow Suur Strait connecting the waters of the V¨ainameri and the Gulf of Riga. During the measurement period wind conditions were extremely variable, including a severe storm on 23 November. The flow speed along the strait varied between ±0.2 m s−1, except for the 0.4 m s−1 that occurred after the storm as a result of the sea level gradient. The mean and maximum significant wave heights were 0.53 m and 1.6 m respectively. Because of their longer fetch, southerly winds generated higher waves in the strait than winds from the north. All wave events caused by the stronger southerly winds induced sediment resuspension, whereas the current-induced shear velocity slightly exceeded the critical value for resuspension only when the current speed was 0.4 m s−1. A triplenested two-dimensional high resolution (100 m in the Suur Strait) circulation model and the SWAN wave model were used to simulate water exchange in 2008 and the wave-induced shear velocity field in the Suur Strait respectively. Circulation model simulations demonstrated that water exchange was highly variable, that cumulative transport followed an evident seasonal cycle, and that there was an gross annual outflow of 23 km3 from the Gulf of Riga. The horizontal distribution of waveinduced shear velocity during the strong southerly wind event indicated large shear velocities and substantial horizontal variability. The shear velocities were less than the critical value for resuspension in the deep area of the Suur Strait.
Źródło:
Oceanologia; 2011, 53, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sediment transport beyond the surf zone under waves and currents of the non-tidal sea: Lubiatowo (Poland) case study
Autorzy:
Ostrowski, R.
Stella, M.
Powiązania:
https://bibliotekanauki.pl/articles/241109.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
wave-induced nearbed oscillations
sea currents
wind-driven current
sand grain diameter
bed shear stress
friction velocity
sediment transport
Opis:
The paper deals with the sandy coastal zone at Lubiatowo in Poland (the south Baltic Sea). The study comprises experimental and theoretical investigations of hydrodynamic and lithodynamic processes in the coastal region located close to the seaward boundary of the surf zone and beyond the surf zone. The analysis is based on field data collected at the IBW PAN Coastal Research Station in Lubiatowo. The data consist of wind velocity reconstructed from the long-term wave climate, deep-water wave buoy records and sea bottom soil parameters. Nearbed flow velocities induced by waves and currents, as well as bed shear stresses are theoretically modelled for various conditions to determine sediment motion regimes in the considered area. The paper discusses the possibility of occasional intensive sediment transport and the occurrence of distinct sea bed changes at bigger water depths.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2016, 63, 1; 63-77
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wind shear detection based on direct measurements, remote sensing and numerical models
Autorzy:
Chaładyniak, D.
Jasiński, J.
Pietrek, S.
Krawczyk, K.
Powiązania:
https://bibliotekanauki.pl/articles/135669.pdf
Data publikacji:
2016
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
wind shear
vertical air currents
omega equation
sonars
radars
wind profilers
WRF model
Opis:
Wind has huge influence on take-off, landing and cruising of aircraft. Therefore measuring wind direction and speed as well as evaluating its structure are the most important tasks in meteorological support of flights. Wind shear, which is characterized by rapid changes of speed and/or direction, is one of the most hazardous phenomena for aviation. This phenomenon exists mostly in low tropospheric jet streams, areas of active atmospheric fronts, near convective clouds and strong temperature inversions. The paper proves that wind shear is mainly dependent on non-uniform layout of ascending and descending air currents and shows that this phenomenon can be detected by using ground sensors (ultrasonic anemometers), remote sensing methods (sodars, radars, wind profilers) and data from numerical mesoscale models.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2016, 48 (120); 75-80
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wave-induced bottom shear stress estimation in shallow water exemplified by using deep water wind statistics
Autorzy:
Myrhaug, D.
Powiązania:
https://bibliotekanauki.pl/articles/47582.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
shallow water
deep water
wind
water
circulation model
shear stress
mud deposit
coastal zone
estuarine zone
bottom sediment
Opis:
The paper provides a simple and analytical method which can be used to give estimates of the wave-induced bottom shear stress for very rough beds and mud beds in shallow water based on wind statistics in deep water. This is exemplified by using long-term wind statistics from the northern North Sea, and by providing examples representing realistic field conditions. Based on, for example, global wind statistics, the present results can be used to make estimates of the bottom shear stress in shallow water.
Źródło:
Oceanologia; 2017, 59, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of shear modulus of soil in the RC / TS apparatus for designing offshore wind power plant foundations
Autorzy:
Srokosz, P.
Dyka, I.
Bujko, M.
Powiązania:
https://bibliotekanauki.pl/articles/260227.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
offshore wind power
shear modulus
back analysis
numerical modelling
Opis:
The paper presents a selected aspect of the determining the initial soil shear modulus value on the research example in resonant column – torsional shear apparatus (RC / TS). There are presented the significance of the initial value of shear modulus in design of offshore wind power plant foundations and the importance of its variability in the function of cyclical shear strains of soil related to the impact of sea and atmosphere on the designed structures. Based on the conducted analyses, a new methodology for interpreting the TS test results of soil has been proposed. It allows estimating the values of the shear modulus in the full range of shear strains occurring in issues closely related to the design and construction work of offshore wind power plant foundations.
Źródło:
Polish Maritime Research; 2018, 3; 69-83
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synoptic conditions of the derecho storm. Case study of the derecho event over Poland on August 11, 2017
Autorzy:
Wrona, Barbara
Mańczak, Piotr
Woźniak, Anna
Ogrodnik, Michał
Folwarski, Michał
Powiązania:
https://bibliotekanauki.pl/articles/2142337.pdf
Data publikacji:
2022
Wydawca:
Instytut Meteorologii i Gospodarki Wodnej - Państwowy Instytut Badawczy
Tematy:
derecho
synoptic analysis
large scale lifting
wind shear
Opis:
This study presents a comprehensive synoptic analysis of one of the most violent storms recorded in recent years in the northwestern part of Poland, which occurred on August 11, 2017. Its development took place ahead of a waving cold front in the tropical air mass, downstream of the upper-level trough. The thunderstorms formed over Lower Silesia in the afternoon and moved towards Gdańsk Pomerania to occur over the Baltic Sea after midnight on August 12, 2017, where they gradually disappeared. As the thunderstorms moved through this area, they ranged from single convective cells and unorganized multicell storms through supercell thunderstorms to mesoscale convective systems in the form of bow echo squall lines and the mesoscale convective vortex (MCV). The convective system, evolving over time, fulfilled the derecho criteria. Its development was related to the presence of both the upper and mid-level jet stream, which supported the formation of a strong rear inflow jet (RIJ) in the rear part of the convective system, being one of the main factors generating the formation of a bow echo squall line with strong wind gusts. The maximum wind gusts recorded on August 11, 2017, are among the highest in the history of Polish measurements and amounted to 42 m/s in Elbląg, 36 m/s in Chrząstów, 35 m/s in Gniezno, and around 30 m/s at several other stations.
Źródło:
Meteorology Hydrology and Water Management. Research and Operational Applications; 2022, 10, 2; 1--25
2299-3835
2353-5652
Pojawia się w:
Meteorology Hydrology and Water Management. Research and Operational Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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