Number of found documents: 2999
Published from to

On the 3D Dynamics of the Wake Behind a Circular Cylinder
Uruba, Václav; Procházka, Pavel P.; Skála, Vladislav
2020 - English
Flow in the wake of a circular cylinder is studied experimentally using time-resolved stereo PIV method. Special attention is paid to 3D topology of dynamical structures. While the distribution of statistic quantities along the cylinder is uniform, and i.e. 2D, the instantaneous flow structure is fully 3D. Within the velocity fluctuating flow field the structures containing streamwise vorticity and velocity components are dominant. The POD modes connected with von Kármán vortex street are identified. Keywords: circular cylinder; wake; 3D structure; POD Fulltext is available at external website.
On the 3D Dynamics of the Wake Behind a Circular Cylinder

Flow in the wake of a circular cylinder is studied experimentally using time-resolved stereo PIV method. Special attention is paid to 3D topology of dynamical structures. While the distribution of ...

Uruba, Václav; Procházka, Pavel P.; Skála, Vladislav
Ústav termomechaniky, 2020

Topical Problems of Fluid Mechanics 2020
Šimurda, David; Bodnár, T.
2020 - English
Proceedings consist of contributions dealing with both research on various problems in fluid mechanics and mathematical or experimental methods utilizable for solution of such problems. Keywords: experimental fluid mechanics; mathematical modelling; CFD; turbulence Available at various institutes of the ASCR
Topical Problems of Fluid Mechanics 2020

Proceedings consist of contributions dealing with both research on various problems in fluid mechanics and mathematical or experimental methods utilizable for solution of such problems.

Šimurda, David; Bodnár, T.
Ústav termomechaniky, 2020

Measurements on TR-W-1 Cascade
Luxa, Martin; Šimurda, David
2020 - English
The research report contains experimetal data from optical and pneumatic measurements on transonic profile cascade with linear part of suction side downstream the sonic line, which is intended for the rotor wheal of a last stage of steam turbine Keywords: transonic flow; steam turbine; profile cascade Available at various institutes of the ASCR
Measurements on TR-W-1 Cascade

The research report contains experimetal data from optical and pneumatic measurements on transonic profile cascade with linear part of suction side downstream the sonic line, which is intended for the ...

Luxa, Martin; Šimurda, David
Ústav termomechaniky, 2020

Measurements on TR-W-2 Cascade
Luxa, Martin; Šimurda, David
2020 - English
The research report contains experimetal data from optical and pneumatic measurements on transonic profile cascade with non-linear part of suction side downstream the sonic line, which is intended for the rotor wheal of a last stage of steam turbine. Keywords: transonic flow; steam turbine; profile cascade Available at various institutes of the ASCR
Measurements on TR-W-2 Cascade

The research report contains experimetal data from optical and pneumatic measurements on transonic profile cascade with non-linear part of suction side downstream the sonic line, which is intended for ...

Luxa, Martin; Šimurda, David
Ústav termomechaniky, 2020

An experimental investigation of yield surfaces anisotropies
Štefan, Jan; Parma, Slavomír; Marek, René; Plešek, Jiří; Feigenbaum, H. P.; Ciocanel, C.
2020 - English
This contribution is dedicated to a rigorous experimental procedure for evaluation of yield surfaces of common metallic materials. This yield surface tracing procedure employs thin-walled tubular specimens to identify individual yield points of the material under arbitrary combinations of axial load and torque. A yield point is identified on the basis of a prescribed threshold for the effective plastic strain that is being continuously and fully automatically evaluated throughout the test. The experimental results generated with this tracing method are promising, leading to shapes of the yield surfaces conform with the von Mises criterion. The proposed methodology can effectively capture the YS shape. Keywords: experimental mechanics; yield surface; directional distortional hardening; metallic materials Available at various institutes of the ASCR
An experimental investigation of yield surfaces anisotropies

This contribution is dedicated to a rigorous experimental procedure for evaluation of yield surfaces of common metallic materials. This yield surface tracing procedure employs thin-walled tubular ...

Štefan, Jan; Parma, Slavomír; Marek, René; Plešek, Jiří; Feigenbaum, H. P.; Ciocanel, C.
Ústav termomechaniky, 2020

Modification of the Algebraic Transition Model for Wall Roughness Effect Including a Rough Strip
Straka, P.; Příhoda, Jaromír
2020 - English
The contribution deals with the simulation of the laminar/turbulent transition on a rough wall. The algebraic transition model taking into account wall roughness according to Straka and Příhoda [8] was further extended for the effect of short rough strip near the leading edge. The proposed correlation was tested by means of incompressible flow over a flat plate covered by sand paper and around the NACA 0012 airfoil with a rough strip near the leading edge. The agreement with experiments is appropriate nevertheless the applicability of the correlation is limited due to the lack of relevant experimental results. Keywords: bypass-transition; wall roughness; rough strip Fulltext is available at external website.
Modification of the Algebraic Transition Model for Wall Roughness Effect Including a Rough Strip

The contribution deals with the simulation of the laminar/turbulent transition on a rough wall. The algebraic transition model taking into account wall roughness according to Straka and Příhoda [8] ...

Straka, P.; Příhoda, Jaromír
Ústav termomechaniky, 2020

Zapalovací a napájecí systém rtuťové výbojky OSRAM 1000W/D
Zajíček, Antonín; Šonský, Jiří
2020 - Czech
Zpráva obsahuje popis zapalovacího a napájecího systému pro rtuťovou vysokotlakou výbojku OSRAM HBO 1000W/D, která je využívána při optických měřeních nestacionárních proudových polí metodou interferometrickou a šlírovou v Aerodynamické laboratoři v Novém Kníně. Zpráva rovněž obsahuje návod k použití celé napájecí soustavy. The report contains description of power supply and ignitor of high pressure mercury lamp OSRAM HBO 1000W/D. The lamp is utilized during optical measurements of transient flow fields, especifically for interferometry and schlieren photography in the Nový Knín aerodynamic laboratory. The report also contains user manual for the power supply chain. Keywords: high pressure mercury lamp; lamp ignitor; lamp power supply Available at various institutes of the ASCR
Zapalovací a napájecí systém rtuťové výbojky OSRAM 1000W/D

Zpráva obsahuje popis zapalovacího a napájecího systému pro rtuťovou vysokotlakou výbojku OSRAM HBO 1000W/D, která je využívána při optických měřeních nestacionárních proudových polí metodou ...

Zajíček, Antonín; Šonský, Jiří
Ústav termomechaniky, 2020

Study on Performance of Various Turbulent Heat Transfer Closures
Louda, Petr; Příhoda, Jaromír
2020 - English
The work compares results of several turbulent heat flux models with different complexity. Authors consider eddy diffusivity model as well as generalized gradient hypothesis and explicit algebraic closures. The results are obtained for backward facing step with heated bottom wall and compared with measurements. Keywords: backward facing step; turbulent heat flux Fulltext is available at external website.
Study on Performance of Various Turbulent Heat Transfer Closures

The work compares results of several turbulent heat flux models with different complexity. Authors consider eddy diffusivity model as well as generalized gradient hypothesis and explicit algebraic ...

Louda, Petr; Příhoda, Jaromír
Ústav termomechaniky, 2020

Large Scale Motions in Turbulent Flows
Kellnerová, Radka; Jurčáková, Klára; Procházka, Pavel P.
2019 - English
Quadrant analysis based on the Reynolds decomposition was performed on the data from turbulent boundary layer flows above variously rough surfaces. An estimation of a convective velocity for events significant in terms of momentum flux, and the statistics of a length and amplitude of the individual events, together with their spectral analysis, was performed. Based on the analyses, we were able to detect a few individual sweep and ejection events with a length longer than 6δ, which could be considered as very large scale motions (VLSM). We also identified number of events with a longitudinal dimension equal to approximately 3δ labelled as large scale motions (LSM). The analyses were executed for various Reynolds numbers. The number of detected structures increases with the momentum of the flow. Keywords: wind tunnel; large scale motion; quadrant analysis Fulltext is available at external website.
Large Scale Motions in Turbulent Flows

Quadrant analysis based on the Reynolds decomposition was performed on the data from turbulent boundary layer flows above variously rough surfaces. An estimation of a convective velocity for events ...

Kellnerová, Radka; Jurčáková, Klára; Procházka, Pavel P.
Ústav termomechaniky, 2019

Assessing Quality of Boundary Layer Flows With the Diagnostic Plot
Jurčáková, Klára; Procházka, Pavel P.; Kellnerová, Radka
2019 - English
We experimentally investigated turbulent boundary layers over 4 rough surfaces and 1 smooth surface by particle image velocimetry for a range a free stream velocities. The obtained mean velocity vertical profiles were universally scaled by roughness length z₀ and friction velocity u*, but both parameters have to be obtained from the fit of the logarithmic or composite velocity pro le to the experimental data. Diagnostic plot, which relates turbulence intensity with the mean velocity showed good collapse of different free stream velocities for each surface. It became fully universal in its modified version when the roughness function was taken into an account. We found that turbulence intensities over our surfaces are higher than any published one and that they dependent on roughness length z₀*. Keywords: wind tunnel; turbulence intensity; rough-wall; friction velocity Fulltext is available at external website.
Assessing Quality of Boundary Layer Flows With the Diagnostic Plot

We experimentally investigated turbulent boundary layers over 4 rough surfaces and 1 smooth surface by particle image velocimetry for a range a free stream velocities. The obtained mean velocity ...

Jurčáková, Klára; Procházka, Pavel P.; Kellnerová, Radka
Ústav termomechaniky, 2019

About project

NRGL provides central access to information on grey literature produced in the Czech Republic in the fields of science, research and education. You can find more information about grey literature and NRGL at service web

Send your suggestions and comments to nusl@techlib.cz

Provider

http://www.techlib.cz

Facebook

Other bases