Number of found documents: 1659
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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

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

On Yield Surface Detection, Experiments by Finite Element Method
Klepač, Vilém; Liu, Li-Wei
2019 - English
In the submitted report it is described, how experiments by FEM are designed for\nmore precise detection of yield point. Content of report can be devided to these\nareas:\n- Intership travel report\n- Idea of research topic\n- Develop software tools Keywords: FEM; yield surface; plasticity Available at various institutes of the ASCR
On Yield Surface Detection, Experiments by Finite Element Method

In the submitted report it is described, how experiments by FEM are designed for\nmore precise detection of yield point. Content of report can be devided to these\nareas:\n- Intership travel ...

Klepač, Vilém; Liu, Li-Wei
Ústav termomechaniky, 2019

Utilization of Convolution Neural Network Based Road Detection in Mobile Robot Localization
Krejsa, Jiří; Věchet, Stanislav
2019 - English
Mobile robot on-road navigation requires fusion of both global and local sensory information with an emphasis on the road detection processing. The paper deals with the road detection based on convolution neural networks (CNN) using commonly available tools such as TensorFlow and Keras. The road is defined by its linear boundaries. Network output is formed by the road definition together with classification parameters and serves as a local sensor in Kalman filter based localization. CNN based road detection is currently capable to successfully detect about 90% of images. Keywords: convolution neural network; localization; road detection Available at various institutes of the ASCR
Utilization of Convolution Neural Network Based Road Detection in Mobile Robot Localization

Mobile robot on-road navigation requires fusion of both global and local sensory information with an emphasis on the road detection processing. The paper deals with the road detection based on ...

Krejsa, Jiří; Věchet, Stanislav
Ústav termomechaniky, 2019

Real-time diagnostics for ROS running systems based on probabilistic patterns identification
Věchet, Stanislav; Krejsa, Jiří
2019 - English
Autonomous mobile robots consists of various software modules to achieve given goal, including solving complex navigation tasks as localization, mapping or path planning. These tasks are highly dependent on the quality of data measured and gathered from hardware subsystems. Using Robot Operating System (ROS) as integration basis reduces the development effort and time to market. While ROS framework itself is considered as reliable and stable to run even soft real-time tasks, in case of any internal failures on data misreadings can be problematic to debug or even identify the problem for common user. Due to this unpleasant situations we develop a virtual assistant, internally represented as diagnostic expert system, to help users to identify and possibly fix the problem. Keywords: diagnostic expert system; bayesian network; system diagnostic Available at various institutes of the ASCR
Real-time diagnostics for ROS running systems based on probabilistic patterns identification

Autonomous mobile robots consists of various software modules to achieve given goal, including solving complex navigation tasks as localization, mapping or path planning. These tasks are highly ...

Věchet, Stanislav; Krejsa, Jiří
Ústav termomechaniky, 2019

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