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Matematické modelování proudění krve
Michalová, Marie ; Hron, Jaroslav (advisor) ; Průša, Vít (referee)
At first we point out some important properties and behaviour of blood and blood particles. In the next part we approximate steady two-dimensional Pois- seiulle flow between two parallel plates. We show analytical solutions for New- tonian and power-law models. According to observations of Fahraeus-Lindquist effect we show two-layer models combining previously mentioned models. In the last section we model pulsatile Poisseuille flow and we show analytical and nu- merical results for some pressure and viscosity values. In the end we show our best model, where we shift pressure gradient and get closer to the real blood flow characteristics. 1
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Matematické modelování proudění krve
Michalová, Marie ; Hron, Jaroslav (advisor) ; Průša, Vít (referee)
At first we point out some important properties and behaviour of blood and blood particles. In the next part we approximate steady two-dimensional Pois- seiulle flow between two parallel plates. We show analytical solutions for New- tonian and power-law models. According to observations of Fahraeus-Lindquist effect we show two-layer models combining previously mentioned models. In the last section we model pulsatile Poisseuille flow and we show analytical and nu- merical results for some pressure and viscosity values. In the end we show our best model, where we shift pressure gradient and get closer to the real blood flow characteristics. 1
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BASIC CHARACTERISTICS OF ARRAY OF PULSATILE JET
Novotný, P. ; Vít, Tomáš ; Vestfálová, M.
The presented paper shows the results of measurement of basic characteristics of array of pulsatile jets which are used to enhance the efficiency of ejectors. Four pulsatile jets forms cross like structure where perpendicular couples are operating in two basic modes (a) in phase and (b) in antiphase. Paper presents phase averaged velocity profiles and velocity fields. All of the presented experiments are realized using hot wire anemometry method.
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Digital holografic interferometry used for identification of 2D temperature field
Lédl, V. ; Vít, Tomáš ; Doleček, R. ; Psota, P.
The presented paper shows the possibility of digital holographic interferometry application in measurement of unsteady 2D temperature field generated by pulsatile flow which is impinging heated surface. Special holographic setup with double sensitivity was developed instead of the commonly used Mach-Zehnder type of holographic interferometer in order to attain the parameters sufficient for the studied case. This setup is not light efficient like the Mach- Zehnder type but has double sensitivity. The results from the digital holographic interferometry experiments are perfected by measurement of the velocity field achieved by methods of hot-wire anemometry.
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Active control of an annular jet by means of the radial synthetic jet
Broučková, Zuzana ; Kordík, Jozef ; Trávníček, Zdeněk
This experimental study deals with an annular jet, which is actively controlled. Firstly, the following partial tasks were measured: axisymmetric continual jet, axisymmetric synthetic jet, radial synthetic jet, and annular jet without control. Measurement was performed in air by means of the Pitot probe and hot-wire anemometer. The results of partial steady tasks confirm knowledge, available from literature. The expected resonant behavior of the synthetic jet actuators was confirmed too. A possibility of flow control of the mean annular jet was proved. A suitable frequency and amplitude of the control synthetic jet was 600Hz and 23m/s, respectively.
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Investigation of Reynolds Stress in Fluid Flow
Adamec, J. ; Nožička, J. ; Kořenář, Josef
In the case of pulsatile flow we are dealing with a complicated task taking in account a non-stationary characters of the process. The change of flow characteristics is of fundamental importance for the solution of many technical problems. The investigation of pulsatile Newtoninan fluid flow in circular rigid pipes is presented in the paper.
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Short-time turbulent disturbances in pulsatile flow
Kořenář, Josef
In the pulsatile flow in tubes near the laminar/turbulent transition zone, the short-time turbulent disturbances arise and fade away in every period. Moment of arise, endurance, course of intensity and moment of disappearing of those disturbances within a period are dependent on flow parameters like mean Reynolds number, Womersley number and flow rate ratio.
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