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Start Over Creator Trávníček, Zdeněk

2. From the singing telegraph wires to the temperature control of wakes

Creator:
Trávníček, Zdeněk
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
vortex shedding, Kármán vortex street, laminar flow, heated circular cylinder, heated transfer, and effective temperature
Language:
English
Description:
Vortex shedding from a bluff body is a classical problem as well as an exciting challenge for fluid mechanics. Since the time of Prof. Strouhal at the end of the 19th century, the phenomenon has been frequently studied by several generations of researchers. This contribution introduces (1) the historical contest of the milestone studies, (2) motivations and goals of the recent investigations, and (3) recent original results of research on the fluid dynamics and heat transfer of heated and cooled circular cylinders in the cross-flow, obtained mainly in the Institute of Thermomechanics. and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Holographic interferometry as a tool for visualization of temperature fields in air

Creator:
Dančová, Petra, Vít, Tomáš, Lédl, Vít, Trávníček, Zdeněk, and Doleček, Roman
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Digital Holographic Interferometry (DHI), temperature fields, Mach-Zehnder holographic interferometer, and Twymann-Green interferometer
Language:
English
Description:
Measurement of temperature field in moving fluids is connected with many difficulties. Usage of point temperature measurement methods, such as Constant Current Anemometry (CCA), is limited to frequencies up to 3 kHz. This frequency should be the limiting factor for using the CCA in fluid when fast change of temperature occurs. This shortcoming of CCA measurements should be overcome by using of optical methods such as Digital Holographic Interferometry (DHI). It is necessary to employ a special holographic setup with double sensitivity instead of the commonly used Mach-Zehnder type of holographic interferometer in order to obtain the parameters sufficient for the studied cases. This setup is not light efficient like the Mach-Zehnder type but has double sensitivity. The article also shows the method of synchronization and the method for phase averaging of the acquired data. The presented DHI is based on a modified Twymann-Green setup. and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public