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O validaci numerického modelu pro simulaci turbulentního proudění s volnou hladinou
Bodnár, T. ; Kozel, K. ; Příhoda, Jaromír
The numerical solution of averaged Navier-Stokes equations with the two-equation SST turbulence model is carried out by means of the VOF method. This approach is based on the assumptions for variable-density incompressible flow with discontinuity in density profile at the free-surface. Numerical solution by means of the finite-volume method utilises the cell-centered scheme on a structured mesh. Numerical results were compared with experimental data for subcritical flow over ribs in an open channel.
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Numerické řešení dvourozměrného proudění v kanálu
Trefilík, J. ; Šimonek, J. ; Kozel, K. ; Příhoda, Jaromír
The work deals with the numerical simulation of viscous incompressible and compressible 2D flows. Numerical solution was carried out by the finite volume method and the Mc Cormack predictor-corrector scheme. Turbulent flow is modelled by an algebraic model and by the two-equation model. Numerical solution of incompressible and compressible flow over the DCA profile in a channel is presented.
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Interakce proudění v kanále s pohybujícími se tělesy
Růžička, M. ; Feistauer, M. ; Horáček, Jaromír ; Sváček, Petr
The subject of this paper is the numerical simulation of the interaction of two-dimensional incompressible viscous flow through a channel (wind tunnel) and a vibrating airfoil. A solid airfoil with two degrees of freedom, which can rotate around the elastic axis and oscillate in the vertical direction, is considered. The numerical simulation consists of the finite element soulution of the Navier-Stokes equations coupled with the system of ordinary differential equations describing the airfoil motion. We discuss the discretization of the problem and present some computational results.
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The evolution of Bečva river stream channel after the flood of 1997 ů the significance for research and protection
Kirchner, Karel ; Lacina, Jan ; Krejčí, O.
The flood of July 1997 altered the stream channel of middle and downstream reach of Bečva river in a significant way. Lateral as well as depth erosion removed upper layers of floodplain sediments and created new well pronounced two-level channel with variety of other fluvial forms, which have profoundly increased the biodiversity of the floodplain landscape. We focused our attention on apprehension of selected long persisting effects of flood on relief, rock environment and floodplain ecosystems as well as the possibilities of their conservation within the selected areas in the vicinity of Choryně (Vsetín District)
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Composing Data-driven Circuits Using Handshake in the Clock-Synchronous Domain
Sýkora, Jaroslav
We present a technique for modelling and synthesis of fine-grained data-driven circuits in the clock-synchronous hardware, such as the field programmable gate arrays (FPGA), called the Flow-Transfer Level (FTL). The distinguishing property of the FTL technique is that it does not rely on FIFO queues to handle flow synchronization between the components (called operators). The communication channels, called pipes, employ conceptually a two-state handshake protocol. The handshake behaviour of each operator is defined logically using dependency subgraphs that are symmetrical for producers and consumers. The original data-flow netlist of operators is transformed into a global control dependency graph. Cycles in dependency graphs are allowed as long as they do not constitute real data dependencies but only dependencies in promises of handshake completions. A method is given that recursively eliminates these cycles.
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Study of resonance and threshold effects on simple two-channel model
Kocák, Jakub ; Čížek, Martin (advisor) ; Kolorenč, Přemysl (referee)
In this thesis we study simple one-dimensional two-channel scattering model where pointlike coupling between channels is provided by the delta potential. The scattering task can be completely solved analytically. The solution of the Lippmann-Schwinger equation leads to improper scattering eigenvectors, consequently to scattering S matrix elements and eigenphases. We study how the setting of parameters affects threshold and resonant behaviour (presence, position, width) and the mutual relationship between resonances and poles of the S matrix in complex k-plane. Then we apply projection- operator formalism to model with resonance and the on-shell T matrix is separated into the orthogonal, direct and resonant term. We discuss how choice of subspace of quasi-bound states effects the separation. Powered by TCPDF (www.tcpdf.org)
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Diagnostika toku v kanále za náhlým rozšířením
Tihon, Jaroslav
A backward-facing step flow is studied by measuring the instantaneous wall shear rate along the channel certenline. A two-step electrodiffusion probe is applied to provide information on the flow direction in the near-wall region. The wall shear rate profiles behind the step are measured and the position of reattachment point detected. The Reynolds numbers examined cover the laminar, transient and beginning of turbulent flow regime. The results are found to be in a good agreement with the experimental and numerical data previously published for the same channel geometry.
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