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Wyszukujesz frazę "wave velocity" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Influence of visco-elasticity on pressure wave velocity in polyethylene MDPE pipe
Autorzy:
Mitosek, M.
Chorzelski, M.
Powiązania:
https://bibliotekanauki.pl/articles/241508.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
water hammer
pressure wave velocity
viscoelasticity
polyethylene MDPE pipe
Opis:
Many of the pipe materials, like polyethylene (MDPE, HDPE) or polypro-pylene (PP), turn out to be visco-elastic. The materials in particular, prove to have strongly time-dependent strain properties. As the propa-gation velocity of pressure waves primarily depends on the fluid bulk modulus and the elasticity of the pipe wall, the above material property has considered the influence in unsteady pipe flow (e.g. in water ham-mer). The pressure velocity in visco-elastic pipes depends on the pres-sure oscillation frequency. The applicability of the method of MOC char-acteristics is limited in the sense that purely elastic strain behaviour has to be assumed. In order to take into account the special properties of visco-elastic pipes, the parameters of the Kelvin-Voigt elements, as well as a complex Young's modulus (dynamic modulus of elasticity) are used to described the pressure velocity. The use of the complex wave velocity seems to be especially useful. However, the velocity should be meas-ured during unsteady water flow. The experiments carried out show that pressure disturbance velocity in MDPE pipe strongly depends on the length of the pipe-line. The velocity increases noticeably when the length of the pipe decreases.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2003, 50, 2; 127-140
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Uncertainties in Determination of Sediment Transport Rates in Coastal Regions
Autorzy:
Ostrowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/241200.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
waves
wave-driven currents
bed shear stresses
friction velocity
sediment transport
Opis:
The paper deals with research uncertainties, difficulties, inaccuracies and unreliabilities related to the modelling of physical phenomena involving coastal lithodynamics. The considerations are focused on processes of wave transformation, wave-driven currents and sediment transport itself. It is shown that possible inaccuracies at individual stages of the modelling of coastal hydrodynamics can lead to serious uncertainties with respect to the ultimate modelling output, namely bed shear stresses and sediment transport rates. These inaccuracies result mostly from arbitrarily assumed parameters and constants. Other modelling biases discussed in the paper comprise simplifications and approximations with respect to sediment resources and size-graded properties, randomness of hydrodynamic impacts, bottom roughness and land-borne factors involved in coastal lithodynamics.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2016, 63, 4; 265-280
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
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
    Wyświetlanie 1-3 z 3

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