Porównano ze sobą dyskretyzacje wyższego rzędu składników konwekcji oparte o schemat MUSCL dla 3D laminarnego ustalonego przepływu cieczy przez kanał. Wyznaczono rozkład prędkości w kanale zakrzywionym i porównano z eksperymentem. Testowano miarę niedokładności rozwiązań stanowiącą residuum równania energii mechanicznej.
EN
The higher-order schemes based on the MUSCL approach have been compared for the 3D laminar steady flow through a channel. The velocity distribution in the curved channel has been determined and compared with the experimental data. The measure of an inaccuracy of the solution, that was the residuum of the mechanical energy equation, has been tested.
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W artykule przedstawiono założenia, podstawowe równania teoretyczne i algorytm opracowanego programu rozwiązywania przepływów lepkich płynu ściśliwego i nieściśliwego w wirujących i nieruchomych kanałach maszyn przepływowych. Wyniki zobrazowano na przykładzie charakterystyk elementów układu hydraulicznego pompy odśrodkowej o specjalnym przeznaczeniu.
EN
In this paper the assumptions, basic theoretical equations and algorithm of the procedure used for the compressible and uncompressible viscid fluid flow calculations in the rotating and stationary channels of turbomachinery are presented. The results are shown as the characteristics of the hydraulic system elements of the centrifugal pump for special applications.
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A mathematical formulation based on the 1-D NS equations of an unsteady compressible viscous flow in a long one-side closed tube has been presented. The source terms have been estimated on the basis of a solution to the linearized 2-D problem that was obtained earlier. A central spatial discretization and the fourth order Runge-Kutta scheme for time integration have been applied to solve the NS equations. A comparison of outcomes of the model with experimental results for transferring a pressure signal through pneumatic transmission lines has been carried out. Sources of some discrepancies between them have been discussed.
This paper aims at presenting calculating model for predicting long-term equivalent sound level near the airfields. In the vicinity of airports noise is affected not only by landing and taking off aircrafts but also by noisy aircraft ground operations. They are related to run up procedures, taxiing of an aircraft from stand or sleeve to the beginning of the runway and after landing from the runway to the stand. Also noise generated by auxiliary power units (APU) or other external generators used to maintain air-conditioning systems and power electrical equipment during the plane's stop over between flights has influence on the equivalent level. An aircraft is represented by a single point source described by immission relevant sound power level, directivity characteristic, speed of moving along taxiway and time of run-up operation. Noise generated by APU is incorporated into the model as a point source located at stand position. Input data were collected for passenger aircraft at the Wroclaw airport under normal working conditions. The computer program was developed
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