Wyniki wyszukiwania - BazTech

1

Hydropower potential of the lower Vistula

Szydłowski M., Gąsiorowski D., Szymkiewicz R., Zima P., Hakiel J.

Acta Energetica

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2015

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nr 1

18--32

EN

This paper presents an estimate analysis of the hydropower potential of the lower Vistula River from Warsaw to Gdańsk Bay. The calculations were made for a hydraulic model of the lower Vistula which takes into account potential development of barrages in a cascade system. Results obtained from the model simulations and from hydrological calculations were used to estimate the power of hydropower plants and the average annual energy output from the entire cascade system. The results of calculations indicate significant energy benefits resulting from the development of a cascade of hydropower plants in the lower Vistula. This study does not discuss the cascade project’s economic viability or other aspects of its development (inland waterways, flood control, etc.).

PL

W artykule przedstawiono szacunkową analizę potencjału hydroenergetycznego dolnej Wisły na odcinku od Warszawy do Zatoki Gdańskiej. Obliczenia wykonano, przyjmując model hydrauliczny dolnej Wisły, w którym uwzględniono potencjalną zabudowę stopniami wodnymi pracującymi w układzie kaskady zwartej. Uzyskane wyniki symulacji z modelu wraz z przeprowadzonymi obliczeniami hydrologicznymi posłużyły do oszacowania mocy elektrowni wodnych oraz średniej rocznej produkcji energii całego układu kaskady. Otrzymane wyniki obliczeń wskazują na znaczące korzyści energetyczne wynikające z budowy kaskady elektrowni wodnych na dolnej Wiśle. W pracy nie podjęto ekonomicznej kwestii opłacalności wykonania analizowanej kaskady, jak również innych aspektów istnienia kaskady (żegluga śródlądowa, ochrona przeciwpowodziowa i inne).

2

Analiza hydraulicznych skutków kaskadyzacji dolnej Wisły

Szydłowski M., Gąsiorowski D., Hakiel J., Zima P., Szymkiewicz R.

Inżynieria Morska i Geotechnika

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2014

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nr 5

420--432

PL

Wstępna ocena wpływu potencjalnej budowy kaskady stopni piętrzących na dolnej Wiśle na warunki przepływu. Numeryczny model hydrauliczny rzeki z uwzględnieniem koncepcji kaskadyzacji dolnej Wisły (KDW). Przedstawienie i interpretacja wstępnych wyników obliczeń hydraulicznych w aspekcie wpływu KDW na bezpieczeństwo publiczne w zakresie ochrony przeciwpowodziowej, a także w odniesieniu do kwestii utworzenia drogi wodnej klasy międzynarodowej Va i produkcji energii elektrycznej.

EN

A preliminary assessment of the impact of the potential construction of dams on the flow conditions in the Vistula river. The numerical model of the river including the concept of the lower Vistula cascade (LVC). The preliminary results and interpretation of hydraulic calculations with regard to the impact of the LVC on the public safety for flood protection. The LVC implications for a creation of the international waterway of the Va class as well as for the electricity production.

3

Modelling of Flood Wave Propagation with Wet-dry Front by One-dimensional Diffusive Wave Equation

Gąsiorowski D.

Archives of Hydro-Engineering and Environmental Mechanics

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2014

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Vol. 61, nr 3-4

111–-125

EN

A full dynamic model in the form of the shallow water equations (SWE) is often useful for reproducing the unsteady flow in open channels, as well as over a floodplain. However, most of the numerical algorithms applied to the solution of the SWE fail when flood wave propagation over an initially dry area is simulated. The main problems are related to the very small or negative values of water depths occurring in the vicinity of a moving wet-dry front, which lead to instability in numerical solutions. To overcome these difficulties, a simplified model in the form of a non-linear diffusive wave equation (DWE) can be used. The diffusive wave approach requires numerical algorithms that are much simpler, and consequently, the computational process is more effective than in the case of the SWE. In this paper, the numerical solution of the one-dimensional DWE based on the modified finite element method is verified in terms of accuracy. The resulting solutions of the DWE are compared with the corresponding benchmark solution of the one-dimensional SWE obtained by means of the finite volume methods. The results of numerical experiments show that the algorithm applied is capable of reproducing the reference solution with satisfactory accuracy even for a rapidly varied wave over a dry bottom.

4

Analysis of floodplain inundation using 2D nonlinear diffusive wave equation solved with splitting technique

Gąsiorowski D.

Acta Geophysica

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2013

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Vol. 61, no. 3

668--689

EN

In the paper a solution of two-dimensional (2D) nonlinear diffusive wave equation in a partially dry and wet domain is considered. The splitting technique which allows to reduce 2D problem into the sequence of one-dimensional (1D) problems is applied. The obtained 1D equations with regard to x and y are spatially discretized using the modified finite element method with the linear shape functions. The applied modification referring to the procedure of spatial integration leads to a more general algorithm involving a weighting parameter. Time integration is carried out using a two-level difference scheme with the weighting parameter as well. The resulting tri-diagonal systems of nonlinear algebraic equations are solved using the Picard iterative method. For particular sets of the weighting parameters, the proposed method takes the form of a standard finite element method and various schemes of the finite difference method. On the other hand, for the linear version of the governing equation, the proper values of the weighting parameters ensure an approximation of 3rd order. Since the diffusive wave equation can be solved no matter whether the area is dry or wet, the numerical computations can be carried out over entire domain of solution without distinguishing a current position of the shoreline which is obtained as a result of solution.

5

Impact of maintenance of floodplains of the Vistula River on high water levels on the section from Włocławek to Toruń

Gąsiorowski D., Szydłowski M.

Acta Energetica

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2013

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nr 3

112--120

EN

This article describes the methodology of hydraulic calculations to estimate the water levels in open channels for steady gradually varied flow. The presented method has been used to analyse the water level on the Vistula River from Włocławek cross-section to Toruń cross-section. The HEC-RAS modelling system has been used for parameterization of the river channel and flood¬plains, as well as for flow simulation. The results obtained have been the basis for assessing the impact of maintenance of floodplains on water level during maximum discharges.

PL

W artykule opisano metodykę obliczeń hydraulicznych umożliwiających wyznaczenie układu zwierciadła wody w korytach otwartych w warunkach wolnozmiennego przepływu ustalonego. Wybraną metodę wykorzystano do analizy układu zwierciadła wody w rzece Wiśle na odcinku od przekroju Włocławek do przekroju Toruń. Do parametryzacji koryta i terenów zalewowych rzeki, jak również do symulacji przepływu, wykorzystano program obliczeniowy HEC-RAS. Na podstawie uzyskanych wyników oceniono wpływ stanu utrzymania terenów zalewowych na położenie zwierciadła w trakcie występowania przepływów maksymalnych.

6

Solution of the Dike-break Problem Using Finite Volume Method and Splitting Technique

Gąsiorowski D.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2011

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Vol. 15, No 3-4

251-270

EN

In this paper, an approach using the finite volume method (FVM) for the solution of two-dimensional shallow water equations is described. Such equations are frequently used to simulate dam-break and dike-break induced flows. The applied numerical algorithm of the FVM is based on a wave-propagation algorithm, which ensures a stable solution and, simultaneously, minimizes numerical errors. Dimensional decomposition according to the coordinate directions was used to split two-dimensional shallow water equations into one-dimensional equations. Additionally, splitting was also applied with respect to the physical processes. The applied dimensional and physical splitting, together with the wave-propagation algorithm led to an effective algorithm and ensured proper incorporation of source terms into the scheme of the finite volume method. A detailed description of an approximation for numerical fluxes and source terms is presented. The obtained numerical results are compared with analytical solutions, laboratory experiments and other results available in the literature.

7

Flood Routing by the Non-Linear Muskingum Model: Conservation of Mass and Momentum

Gąsiorowski D.

Archives of Hydro-Engineering and Environmental Mechanics

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2009

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Vol. 56, nr 3-4

121-137

EN

In this paper, the conservative properties of the Muskingum equation, commonly applied to solve river flood routing, are analysed. The aim of this analysis is to explain the causes of the mass balance error, which is observed in the numerical solutions of its non-linear form. The linear Muskingum model has been considered as a semi-discrete form of the kinematic wave equation and therefore it was possible to derive its two non-linear forms. Both forms were derived directly from the kinematic wave equation. It appeared that depending on the assumed conservative form of the Muskingum equation, this model satisfies either the global mass conservation law or the global momentum conservation law. Both laws are satisfied simultaneously by the linear equation only. The mass balance error can be eliminated from the numerical solution on condition that the non-linear Muskingum equation is written in the proper conservative form.

8

Balance errors in numerical solutions of shallow water equations

Gąsiorowski D.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2007

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Vol. 11, No 4

329-340

EN

An analysis of the conservative properties of shallow water equations is presented, focused on the consistency of their numerical solution with the conservation laws of mass and momentum. Two different conservative forms are considered, solved by an implicit box scheme. Theoretical analysis supported with numerical experiments is carried out for a rectangular channel and arbitrarily assumed flow conditions. The improper conservative form of the dynamic equation is shown not to guarantee a correct solution with respect to the conservation of momentum. Consequently, momentum balance errors occur in the numerical solution. These errors occur when artificial diffusion is simultaneously generated by a numerical algorithm.

9

Estymacja prawdopodobieństwa fonemów w neuronowym systemie rozpoznawania mowy

Gąsiorowski D.

Elektronika : konstrukcje, technologie, zastosowania

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2003

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Vol. 44, nr 5-6

37-39

PL

Zaprezentowano nowoczesną metodę estymacji prawdopodobieństwa fonemów za pomocą sztucznych sieci neuronowych na potrzeby automatycznego systemu rozpoznawania mowy (ARM). Wykorzystano przy tym technologię cyfrowego przetwarzania sygnałów do ekstrakcji charakterystycznych cech (melowe częstotliwościowe współczynniki kepstralne - MFCC). Przedstawiono dwa rodzaje estymatorów neuronowych: wielostanowe sieci neuronowe z czasowymi opóźnieniami (MS-TDNN) oraz samoorganizującą się mapę Kohonena (SOM) z czasowymi oknami opóźnień.

EN

This thesis presents modern method for phoneme probability estimation with Artificial Neural Networks (ANN) to use Automatic Speech Recognition (ASR) system. The digital signal processing technology pro-vide a feature extraction (mel frequency cepstral coefficients - MFCC). Presents two kinds of neural estimations: Multi-State Time Delay Neural Network (MS-TDNN) or Kohonen Self-Organizing Map (SOM) with time-delay Windows.