Yanovych, Vitalii
,
Duda, Daniel
,
Uruba, Václav
,
Procházka, Pavel
,
Antoš, Pavel
Effect of Cylinder Roughness on Strouhal Number
The main goal of this paper is to establish a better understanding of the relationship between a Strouhal number and surface roughness. Hot-wire anemometry was used to evaluations the characteristics of turbulent flow behind circular cylinders with different relative roughness 0% (smooth... |
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Yanovych, Vitalii
,
Duda, Daniel
,
Uruba, Václav
,
Kosiak, Pavlo
The structure of turbulent flow behind the NACA 0012 airfoil at high angles of attack and low Reynolds number
This paper shows the results of a study of the turbulent structure behind the NACA 0012 airfoil. During the experiment, the flow velocity was 20 m·s−1. That corresponds the Reynolds number 1.3·105. The point behind the trailing edge was chosen for experimental studies. Measurements... |
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Kotlan, Václav
,
Hamar, Roman
,
Slobodnik, Karel
,
Dolezel, Ivo
Modeling of temperature patterns and hardness of surfaces obtained by additive technique
Temperature patterns and hardness of surfaces produced by laser cladding is modeled. The mathematical model includes the description of all important physical phenomena taking part in the process. Experimental ... |
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Yanovych, Vitalii
,
Duda, Daniel
,
Uruba, Václav
Dimensional analysis parameters of turbulence in the wake of a square cylinder
In this article, we show the results of a study of the structure of a turbulent flow behind a square cylinder. Namely, for the series of points that have the highest standard deviation value. During the experiment, we were changing the position of the square cylinder ... |
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Duda, Daniel
,
Jelínek, Tomáš
,
Němec, Martin
,
Uruba, Václav
,
Yanovych, Vitalii
,
Žitek, Pavel
Observation of flow structure past a full-stage axial air turbine at the nominal and off-design states
The air flow inside single-stage test turbine is studied experimentally by Particle Image Velocimetry (PIV). Here we report the measurements results at axial-tangential plane just behind the rotor wheel at middle blade radius. We studied one nominal state and two off-design states. We&#... |
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Duda, Daniel
,
Jelínek, Tomáš
,
Němec, Martin
,
Uruba, Václav
,
Yanovych, Vitalii
,
Žitek, Pavel
Particle image velocimetry measurement inside axial air test turbine - Effect of window
We measure the two dimensional instantaneous velocity fields inside an axial turbine by using the technique PIV (Particle Image Velocimetry). The measured plane is located just behind the rotor wheel and it is oriented in axial × tangential direction. We measured a single overloade... |
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Duda, Daniel
,
Yanovych, Vitalii
,
Uruba, Václav
Analysing mysterious turbulence
It is often said that turbulence is the last unsolved problem of classical physics \cite{Uriel}. This is caused by its enormous complexity resulting from the mutual interactions of large number of \emph{objects} of different sizes and strengths -- the \emph{vortices} and other... |
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Yanovych, Vitalii
,
Duda, Daniel
,
Horáček, Vít
,
Uruba, Václav
Research of a wind tunnel parameters by means of cross-section analysis of air flow profiles
Wind tunnel is constructed. It is characterized by a high degree of airflow laminarization. The main constructive element of this aerodynamic tube is the laminarization module. It allows the destruction of turbulent fluxes by providing a homogeneous laminar flow. In order to evaluate&#x... |
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Bém, Jindřich
,
Duda, Daniel
,
Kovařík, Jiří
,
Yanovych, Vitalii
,
Uruba, Václav
Visualization of secondary flow in a corner of a channel
We report observation of secondary flow in one corner of developing channel air flow. Length of the channel, i.e. length of boundary layer, is 400?mm, which is 3.2 times the channel cross-sectional size. Three components of velocity are measured by using a Stereo Particle Imag... |
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Richter, Lukáš
,
Uruba, Václav
,
Procházka, Pavel
,
Volf, Michal
,
Vacková, Michaela
,
Pavlíček, Petr
,
Krejčí, Miroslav
The Reynolds number effect on dynamics of the wake behind a circular cylinder
Circular cylinder in cross-flow was studied experimentally using time-resolved PIV technique. Reynolds numbers based on the cylinder diameter were in range from 3 850 up to 19 260. Effect of the Reynolds number on wake time-mean topology as well as the dynamical behavior is st... |
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Bartoň Klufová, Pavla
Laserové navařování kompozitního materiálu na bázi měď-čedič pro aplikaci v jaderném průmyslu
The paper focuses on the development of a composite copper-basalt laser overlay with high corrosion resistance. The additional material for laser cladding was a powder consisting of a mixture of high purity copper and basalt dust. Within the experimental program, 3 types of powder&... |
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Procházka, Pavel
,
Uruba, Václav
On the Recirculation Zone Behind a Cylinder of Finite Length with Subcritical Aspect Ratio
The Particle Image Velocimetry is utilized to investigate flow behind a cylinder of finite length with subcritical value of Aspect Ratio (AR). The cylinder is submitted to uniform freestream with very low intensity of turbulence and thin laminar boundary layer. The flow field canno... |
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Uruba, Václav
Reynolds Number in Laminar Flows and in Turbulence
Reynolds number is the basic parameter determining the flow-field topology and its evolution in time unambiguously if only inertial, pressure and viscous effects are involved. However the Reynolds number definition is not unique and its physical meaning depends strongly on its actual de... |
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Uruba, Václav
,
Procházka, Pavel
,
Skála, Vladislav
On the 3D dynamics of the wake behing 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 statistic quantities along the cylinder is uniform, and i.e. 2D, the instantaneous flow&#x... |
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Uruba, Václav
,
Procházka, Pavel
POD Spectrum of the Wake behind a Circular Cylinder
The wake dynamics behind a long circular cylinder in cross-flow was studied using the POD method. The temporal parts of POD modes, Chronoses, are subjected to frequency analysis. Five groups of modes are distinguished according to the frequency contents. The low order high energy&#... |
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Procházka, Pavel
,
Uruba, Václav
Reynolds Number Effect on Velocity Field and on Coherent Structures behind a Cylinder
The Particle Image Velocimetry was used to investigate the coherent structures behind a cylinder under moderate Reynolds number. Dynamical decomposition method was used to detect flow patterns having similar frequency as the vortex shedding frequency which is given by Strouhal number. The&#x... |
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Uruba, Václav
,
Procházka, Pavel
,
Skála, Vladislav
Anisotropy of Turbulent Flow around an Airfoil
The flow around an airfoil is analyzed from the point of view turbulence anisotropy assessment. The turbulent flow-field in the vicinity of an airfoil is populated by vortices, in some locations they tend to regularity in orientation, i.e. to anisotropy. However in the wake be... |
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Uruba, Václav
,
Procházka, Pavel
,
Skála, Vladislav
Structure of the Wake Behind an Airfoil
The wake behind an inclined plate simulating airfoil is to be studied experimentally. The vortical structures are identified eventually. Theirs topology and dynamical behaviour is to be studied in details using the Proper Orthogonal Decomposition method. The stereo time resolved Particle Ima... |
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Uruba, Václav
,
Procházka, Pavel
Dynamics of the Tip Vortices in the Wake Behind a Circular Cylinder of Finite Length
The dynamics of the tip vortices in the wake behind a wall-mounted finite-length circular cylinder of the aspect ratio 2 was studied experimentally using time resolved stereo PIV technique. The cylinder was mounted normal to a ground plane and it was subjected to a cross-flow&... |
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Uher, Jan
,
Milčák, Petr
,
Škach, Radek
,
Fenderl, David
,
Žitek, Pavel
,
Klimko, Marek
Experimental and Numerical Evaluation of Losses From Turbine Hub Clearance Flow
Long-term efforts have been made to understand loss generation and its reduction in the field of axial turbomachines. The traditional approach to losses for an isolated blade row considers the profile and the secondary losses as a result of viscous flow. The additional kinds o... |

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Collection's Items (Sorted by Submit Date in Descending order): 1 to 20 of 20

Collection's Items (Sorted by Submit Date in Descending order): 1 to 20 of 20