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Final Report of the Centre of Excellence for Nonlinear Dynamic Behaviour of Advanced Materials in Engineering
Parma, Slavomír; Gabriel, Dušan
2022 - English
This final report presents the CeNDYNMAT Center of Excellence, which was established at the Institute of Thermomechanics of the Czech Academy of Sciences in 2016 and ended in 2022. The report summarizes the most important scientific results of the center. It also gives an overview of the main outcomes and developments of the project, including budgeting, purchasing instrumentation, international cooperation and organization of conferences and summer courses.
Keywords:
nonlinear dynamic behavior; advanced materials; metal plasticity
Available at various institutes of the ASCR
Final Report of the Centre of Excellence for Nonlinear Dynamic Behaviour of Advanced Materials in Engineering
This final report presents the CeNDYNMAT Center of Excellence, which was established at the Institute of Thermomechanics of the Czech Academy of Sciences in 2016 and ended in 2022. The report ...
Problematics of aerodynamic damping calculation from measured data of 5-blade cascade
Šnábl, Pavel; Pešek, Luděk; Prasad, Chandra Shekhar; Chindada, Sony
2022 - English
Aerodynamic damping as a function of inter-blade phase angle (IBPA), so called S-curve, is crucial for assessment of aeroelastic stability of blade cascades, e.g. turbines, compressors, etc.\nFor constructing the S-curve, the motion-induced controlled flutter is introduced to the bladesof the cascade. As decribed in [1], two testing methods exist: aerodynamic influence coefficient\n(AIC) approach and travelling wave mode (TWM) approach. In TWM approach, all blades in a row oscillate with the same frequency and amplitude with various IBPAs. The response is\nmeasured only on the reference blade. With this approach, several measurements with different IPBAs are needed to construct the S-curve. On the other hand, AIC uses single oscillating\nblade and principle of linear superimposition of aerodynamic influence responses measured on all blades in a cascade. The result of one single measurement can be used for estimation of\naerodynamic damping for any IBPA. In the past year a new 5-blade cascade with rotating symmetrical NACA 0010 profiles was designed and built. The blades of the cascade were placed further apart and thus we are now able to reach stall flutter. Also, the suspension of the blades and sensors were significantly improved. Now, our goal is to evaluate S-curves using AIC approach for different flow conditions and oscillation frequencies.
Keywords:
aerodynamic damping; S-curve; blade cascade
Available at various institutes of the ASCR
Problematics of aerodynamic damping calculation from measured data of 5-blade cascade
Aerodynamic damping as a function of inter-blade phase angle (IBPA), so called S-curve, is crucial for assessment of aeroelastic stability of blade cascades, e.g. turbines, compressors, etc.\nFor ...
Determination of current floor during mobile robot elevator ride
Krejsa, Jiří; Věchet, Stanislav; Chen, K. S.
2022 - English
In order for the mobile robot to use the elevator, it must be capable to call the elevator in, detect the control panel, select desired floor and to determine what floor is the elevator located. The paper deals with determination of correct floor the mobile robot is currently at using the processing of onboard accelerometer data. Up to 5 relative floor difference the method exhibits over 95% accuracy.
Keywords:
mobile robot; elevator floor determination; signal processing
Fulltext is available at external website.
Determination of current floor during mobile robot elevator ride
In order for the mobile robot to use the elevator, it must be capable to call the elevator in, detect the control panel, select desired floor and to determine what floor is the elevator located. The ...
Control system architecture for novel experimental microalgae photobioreactor Simbios
Věchet, Stanislav; Krejsa, Jiří; Chen, K. S.
2022 - English
Photo-bioreactors for growing biomass based on various microalgae cultures gains interests nowadays due to have possible positive impact to society because of the potential to serve as an atmospheric carbon dioxide removal (CDR) device, produce food or fuel. We present an overall architecture of a control system designed with focus to keep the photo-bioreactor alive for long term continuous operation without any human supervision needed. To test overall control system stability we design a custom build spiral photo-bioreactor (PBR) with novel hyperbolic shaped illuminated part. The shape of the illuminated part was design with the goal to increase the ratio of spiral part to volume due to the fact that the light is crucial for microalgae to grow. The control system was created from scratch while adopting reliable IoT sensors combined with highly reliable custom build embedded control system including a cloud data processing and storage. As a result we have scalable and reliable solution which is suitable for photo-bioreactors of various shapes and sizes to operate in fully autonomous mode without any human supervision needed.
Keywords:
photobioreactor; IoT sensors; control system,
Fulltext is available at external website.
Control system architecture for novel experimental microalgae photobioreactor Simbios
Photo-bioreactors for growing biomass based on various microalgae cultures gains interests nowadays due to have possible positive impact to society because of the potential to serve as an atmospheric ...
Aerodynamic Measurements on Transonic Compressor Blade Cascades KR-D-5 and KR-D-6
Šimurda, David; Hála, Jindřich; Luxa, Martin
2022 - English
This report contains results and evaluation of aerodynamic measurements conducted on two variant transonic compressor blade cascades with MCA profile (KR-D-5) and DCA profile (KR-D-6).
Keywords:
compressor blade cascade; experiment; transonic flow; MCA profile; DCA profile
Available at various institutes of the ASCR
Aerodynamic Measurements on Transonic Compressor Blade Cascades KR-D-5 and KR-D-6
This report contains results and evaluation of aerodynamic measurements conducted on two variant transonic compressor blade cascades with MCA profile (KR-D-5) and DCA profile (KR-D-6).
Topical Problems of Fluid Mechanics 2022
Šimurda, David; Bodnár, T.
2022 - English
Proceedings consist of papers presented during the conference Topical Problems of Fluid Mechanics 2022. \n
Keywords:
experimental fluid mechanics; mathematical modelling; CFD; turbulence; stratified fluid; multiphase flow; vortex structures; supersonic flow
Available at various institutes of the ASCR
Topical Problems of Fluid Mechanics 2022
Proceedings consist of papers presented during the conference Topical Problems of Fluid Mechanics 2022. \n
Wake Behind a Cylinder: An Overview of Spatio-Temporal Aspects
Uruba, Václav
2022 - English
A circular cylinder in crossflow is subjected to the overview study from the point of view spatial and temporal characteristics. It represents itself a typical engineering problem, appearing in practice frequently in various forms. In fluid mechanics, this case is considered to be a typical canonical case, with relatively simple and straightforward definition, but complex and dynamical flow topology. The typical dynamics is characterized by quasi-periodic behavior called von Kármán – Bénard vortex street with a typical frequency expressed in dimensionless number called Strouhal number. The wake flow structure is considered to be characterized by a single frequency and 2D topology, homogeneous along the cylinder axis, very often. The presented paper concentrates on differences between this commonly accepted model and physical reality. Both temporal and spatial aspects of the flow in the wake behind a cylinder are to be addressed. The turbulent subcritical wake characterized by Reynolds number about 5 thousand will be considered, as this situation is a typical case in mechanical engineering applications.
Keywords:
circular cylinder; wake; vortex; dynamics; 3D structure
Fulltext is available at external website.
Wake Behind a Cylinder: An Overview of Spatio-Temporal Aspects
A circular cylinder in crossflow is subjected to the overview study from the point of view spatial and temporal characteristics. It represents itself a typical engineering problem, appearing in ...
Use of active power filter to reduce flicker caused by electric arc furnace operation
Čerňan, Martin; Bejvl, Martin; Šimek, Petr; Valouch, Viktor
2022 - English
Effectiveness of using a parallel active power filter to compensate for the flicker of an electric arc furnace,\nand mitigate the reactive power consumption and terminal\nvoltage variation in the grid is presented and evaluated in the contribution. The model of a power system with the electric arc furnace and parallel active power filter in the frequency domain has been developed. The selected results of simulation in the frequency domain using the data collected from the 60 t EAF are presented and evaluated.
Keywords:
electric arc furnace; flicker mitigation; active power filter; power system model; simulation in frequency domain
Available at various institutes of the ASCR
Use of active power filter to reduce flicker caused by electric arc furnace operation
Effectiveness of using a parallel active power filter to compensate for the flicker of an electric arc furnace,\nand mitigate the reactive power consumption and terminal\nvoltage variation in the grid ...
Identification of the blade tip possition and measurement techniques using the BTT method
Maturkanič, Dušan; Procházka, Pavel; Hodboď, Robert; Mekhalfia, Mohammed Lamine
2022 - English
This paper describes the existing practice in identifying and defining the position of the blade tips and the relevant technique for measuring their vibration during rotation. In connection with the effort to precisely define the position of the vibrating blade, the paper also analysed the possibilities of unambiguous determination of its position. This work creates a parallel branch to signal processing in the complex system of precision measurement and analysis of blade vibration, which was mentioned in previous papers.
Keywords:
turbine blade; vibration; precision method; modification; harmonic function
Available at various institutes of the ASCR
Identification of the blade tip possition and measurement techniques using the BTT method
This paper describes the existing practice in identifying and defining the position of the blade tips and the relevant technique for measuring their vibration during rotation. In connection with the ...
Measurement and analysis of vibration and acoustic emissions of a railway wheel under defined dynamic excitations
Pešek, Luděk; Prasad, Chandra Shekhar; Šnábl, Pavel
2022 - English
The paper deals with experimental vibro-acoustics of railway wheel. The methodology for evaluation of effect of vibrational plate dampers was elaborated. The four variants of the wheel was measured and analyse to achieve the optimal solution of the dampers.
Keywords:
vibro-acoustics; railway wheel; dampers; noise
Available at various institutes of the ASCR
Measurement and analysis of vibration and acoustic emissions of a railway wheel under defined dynamic excitations
The paper deals with experimental vibro-acoustics of railway wheel. The methodology for evaluation of effect of vibrational plate dampers was elaborated. The four variants of the wheel was measured ...
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