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Collection's Items (Sorted by Submit Date in Descending order): 1 to 20 of 46
Rubanenko, Olena , Miroshnyk, Oleksandr , Shevchenko, Sergiy , Yanovych, Vitalii , Danylchenko, Dmytro , Rubanenko, Oleksandr
Distribution of wind power generation dependently of meteorological factors

Analyses of trends increasing annual wind power plant capacity and power generation in the World and Europe are presented in this paper. Investigated main problems of increasing the power generation of renewable energy sources in distributed power grids. Proposed ways to decide them...

Volf, Michal , Demianenko, Maryna , Starynskyi, Oleksandr , Liaposhchenko, Oleksandr , Pavlenko, Ivan
Numerical Simulation of the Mass-Transfer Process Between Ammonia and Water in the Absorption Chiller

This paper describes the absorption process of gaseous ammonia into liquid water in the plate heat exchanger, which is considered to be the crucial part of an absorption cooling system. Two approaches are utilized to numerically simulate this absorption process. In the first approa...

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...

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...

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...

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...

Rubanenko, Olena , Yanovych, Vitalii , Miroshnyk, Oleksandr , Danylchenko, Dmytro
Hydroelectric power generation for compensation instability of non-guaranteed power plants

This paper presented research small- and minihydroelectric power plants as an effective source of compensation for instability of non-guaranteed renewable energy sources (RES) power plants. HPPs play the main role for balancing the power system operation mode. To somehow compensate for the&#...

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...

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...

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&#...

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...

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...

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...

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...

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&...

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...

Rubanenko, Olena , Yanovych, Vitalii
Analysis of instability generation of photovoltaic power station

We showed an analysis of installed capacity and annual electricity generation of photovoltaic power stations in the world and Ukraine. The main focus of our research was on the analysis of the influence of meteorological factors on power generation. Two photovoltaic power stations ...

Duda, Daniel , Bém, Jindřich , Kovařík, Jiří , Yanovych, Vitalii , Uruba, Václav
Influence of secondary flow corner vortex to boundary layer in a channel flow

Yanovych, Vitalii , Duda, Daniel , Horáček, Vít , Uruba, Václav
Creation of recombination corrective algorithm for research of a wind tunnel parameters

Linhart, Jiří , Rendlová, Zdeňka , Švígler, Jaromír
Inversion of the twin rotary screw compressor to an expander

Collection's Items (Sorted by Submit Date in Descending order): 1 to 20 of 46