Temat: transient pipe flow - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Universal weighting function in modeling transient cavitating pipe flow
Uniwersalna funkcja wagi w modelowaniu niestacjonarnych przepływów z kawitacją występujących w przewodach ciśnieniowych
Autorzy:: Urbanowicz, K.
Zarzycki, Z.
Kudźma, S.
Powiązania:: https://bibliotekanauki.pl/articles/281804.pdf
Data publikacji:: 2012
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: transient pipe flow
unsteady wall shear stress
weighting function
cavitation
Opis:: This work concerns modeling of time-varying resistance during transient cavitating liquid pipe flow. The wall shear stress is presented in the way introduced by Zielke as the integral convolution of liquid local velocity changes and a weighting function. A new procedure for determination, so-called, a universal laminar-turbulent weighting function, which combines functions of Zielke and Vardy and Brown or Zielke and Zarzycki, is presented. Based on these weighting functions, the method of simulation transients in the pressure lines in a wide range of Reynolds numbers is presented. It eliminates numerical problems associated with the change of laminar flow into turbulent and vice versa. An example application of this method for simulation of water hammer is presented. The calculation results are compared against experiments presented by Bergant and Simpson, and good agreement is found.
Praca dotyczy modelowania zmiennych w czasie oporów podczas nieustalonego przepływu cieczy w przewodach ciśnieniowych. Naprężenie styczne na ściance przewodu przedstawione zostało w klasyczny sposób (wg. Zielke) jako całka splotowa z przyśpieszenia cieczy i pewnej funkcji wagowej. Przedstawiono procedury wyznaczania dwóch uniwersalnych funkcji wagowych laminarnoturbulentnych (wg. Zielke i Vardy-Browna oraz wg. Zielke i Zarzyckiego).W oparciu o te funkcje przedstawiono metodę modelowania (symulacji) przebiegów przejściowych w przewodach ciśnieniowych w szerokim zakresie liczb Reynoldsa. Eliminuje on problemy natury numerycznej związane z przechodzeniem min. z przepływu laminarnego w turbulentny i odwrotnie. Podano przykład zastosowania opracowanej metody do symulacji uderzenia hydraulicznego. Wyniki obliczeń porównano z wynikami eksperymentalnymi wg. Berganta i Simpsona, otrzymując dobrą zgodność.
Źródło:: Journal of Theoretical and Applied Mechanics; 2012, 50, 4; 889-902
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Improved lumping friction model for liquid pipe flow
Autorzy:: Urbanowicz, K.
Zarzycki, Z.
Powiązania:: https://bibliotekanauki.pl/articles/280074.pdf
Data publikacji:: 2015
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: transient pipe flow
frequency-dependent friction
effective numerical solution
water hammer
cavitation
Opis:: Normally, during one-dimensional pipe flow, the friction terms are calculated with the use of a numerical method (for example MOC – method of characteristics) at every computational node along the pipe and at every time step. This procedure tends to increase the computational effort greatly. A considerable increase in computational speed can be archived by calculating the frequency-dependent friction at the end of the pipe only. To avoid possible problems (no damping at closed walls, underestimate damping on high impedance components) the frequency-dependent friction term is calculated from the flow waves. The lumping friction model in this work is based on a modificated Schohl convolution integral solution. In addition, the work examined the impact of using of simplified effective weighting function on the obtained results of numerical simulations. The modified method in conjunction with the use of simplified weighting function allow determination of real-time estimate of the basic parameters representing the fluid flow in complex hydraulic systems, water supply, etc.
Źródło:: Journal of Theoretical and Applied Mechanics; 2015, 53, 2; 295-305
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: A numerical approach to the standard model of water hammer with fluid-structure interaction
Autorzy:: Henclik, S.
Powiązania:: https://bibliotekanauki.pl/articles/281051.pdf
Data publikacji:: 2015
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: water hammer
transient pipe flow
fluid-structure interaction
standard model
method of characteristics
Opis:: In the classic water hammer (WH) theory, 1D liquid flow in a quasi-rigid pipe is assumed. When the pipe is flexible or is fixed to the foundation with elastic supports, the dynamic fluid structure interaction (FSI) should be taken into account for more accurate modelling of the system behaviour. The standard model of WH-FSI for a straight pipe reach is governed by fourteen hyperbolic partial differential equations of the first order, two for 1D liquid flow and twelve for 3D motion of the pipe. This model is presented in the paper and an algorithm for its numerical solution based of the method of characteristics is proposed. Basic boundary conditions (BC) are shortly discussed. The important condition at the junction of two subpipes fixed to the foundation with a viscoelastic support is presented in details and a general method of its solution is proposed.
Źródło:: Journal of Theoretical and Applied Mechanics; 2015, 53, 3; 543-555
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Mathematical model and numerical computations of transient pipe flows with fluid-structure interaction
Autorzy:: Henclik, S.
Powiązania:: https://bibliotekanauki.pl/articles/175378.pdf
Data publikacji:: 2010
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: waterhammer
transient pipe flow
fluid-structure interaction (FSI)
numerical modeling
method of characteristics
Opis:: Transient flows in closed conduits are of interest from over a century, but the dynamic interaction between the fluid and the pipe is taken into consideration more thoroughly just from a few decades. A standard model of the phenomenon consists of fourteen first order partial differential equations (PDE), two for a one-dimensional (1D) liquid flow and twelve for 3D pipe motion. In many practical cases however, a simpler four equations (4E) model can be used, where 1D longitudinal pipe movement is assumed. A short description of waterhammer event with fluidstructure interaction taken into account is presented in the article. The 4E mathematical model is presented in detail with the assumptions and main algorithms of computer program that has been developed. Two phase flow is assumed not to take place, but the friction between the liquid and the pipe wall are taken into consideration. A method of characteristics (MOC) with time marching procedure is employed for finding the solutions, but instead of direct solving the resulting finite difference equations (FDE) the “wave method” is proposed. Some other important elements of the algorithm are presented and selected results of numerical computations as well.
Źródło:: Transactions of the Institute of Fluid-Flow Machinery; 2010, 122; 77-94
0079-3205
Pojawia się w:: Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Transient cavitating pipe flow: Computation models and methods
Autorzy:: Urbanowicz, K.
Zarzycki, Z.
Powiązania:: https://bibliotekanauki.pl/articles/1943252.pdf
Data publikacji:: 2008
Wydawca:: Politechnika Gdańska
Tematy:: column separation
bubby flow
numerical simulation
cavitation
transient turbulent pipe flow
unsteady friction
Opis:: The paper presents four key mathematical models of a transient cavitating pipe flow, i.e. the column separation model (CSM), the gas cavitation model (CSMG), Adamkowski’s model (CSMA) and the bubbly cavitation model (BCM). All models investigated in the paper take into account unsteady frictional loss models. The equations describing all models have been solved using the method of characteristics at first and the finite differences method then. The results of numerical simulations have been compared with the results obtained in the experiments. Transients which have taken into account the unsteady wall shear stress fit well with the results of experiments in comparison with the quasi-steady wall shear stress model.
Źródło:: TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2008, 12, 3-4; 159-172
1428-6394
Pojawia się w:: TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Hydraulic analysis of leakage from submarine pipe network
Autorzy:: Li, J. H.
Fan, Y. T.
Powiązania:: https://bibliotekanauki.pl/articles/258776.pdf
Data publikacji:: 2015
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: submarine pipe network
leakage
transient flow
Opis:: The leakage from submarine pipe network is investigated by a numerical model in this paper. A whole event including of the steady flow before the leakage, the transient flow during the leakage and the steady flow after the leakage is considered in the model. The numerical results of the discharge and the head compare with the theoretical solution under the condition of steady flow. Good agreement is obtained. The numerical results of the discharge and the head show that the discharge and the head in each pipe changes suddenly after the leakage occurring. The abrupt trend of the discharge in each pipe is not same completely. Some change upwards, while others downwards. However, the abrupt trend of the head is always downward. The effects of leakage discharge on the transient flow are also investigated. It is founded that the larger the leakage discharge, the more obvious the abrupt trend of the discharge and the head before or after the leakage is.
Źródło:: Polish Maritime Research; 2015, S 1; 48-55
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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