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Závěrečná zpráva o řešení projektu MPO čís. CZ.01.1.02/0.0/0.0ú20_321/0023673
Zolotarev, Igor; Pešek, Luděk; Gabriel, Dušan; Procházka, Pavel P.
2023 - Czech
Projektu MPO s názvem Vývoj rozvaděče pro těžké podmínky a snížení rizik ohrožení kritické infrastruktury byl zaměřen na výzkum, vývoj optimalizované konstrukce a zajištění konfigurační technologie pro opakovanou produkci různých variant modulárního systémového rozváděče pro použití v těžkých podmínkách a snížení rizik seizmického ohrožení, pro zajištění spolehlivosti kritické infrastruktury. Výstupem má být prototyp seizmicky robustního zařízení s dynamicky odlehčené konstrukce, vysokou spolehlivostí funkce sestavy rozvaděče a elektrovýzbroje a SW aplikace pro interaktivní návrhy a dokumentaci. The MIT project entitled Development of a switchgear for severe conditions and reduction of risks of critical infrastructure threat was focused on research, development of optimized design and provision of configuration technology for repeated production of different variants of modular system switchgear for use in severe conditions and reduction of risks of seismic threat, to ensure the reliability of critical infrastructure. The output is to be a prototype seismically robust device with a dynamically lightweight design, high reliability of switchgear and electrical equipment assembly function, and a software application for interactive design and documentation.
Keywords:
vibration; natural frequencies; modes of vibration; seismic resistance; dynamic properties of structures
Available at various institutes of the ASCR
Závěrečná zpráva o řešení projektu MPO čís. CZ.01.1.02/0.0/0.0ú20_321/0023673
Projektu MPO s názvem Vývoj rozvaděče pro těžké podmínky a snížení rizik ohrožení kritické infrastruktury byl zaměřen na výzkum, vývoj optimalizované konstrukce a zajištění konfigurační technologie ...
Simulating particle-laden flows: from immersed boundaries towards model order reduction
Isoz, Martin; Kubíčková, Lucie; Kotouč Šourek, M.; Studeník, Ondřej; Kovárnová, A.
2023 - English
Particle-laden flow is prevalent both in nature and in industry. Its appearance ranges from the trans-port of riverbed sediments towards the magma flow, from the deposition of catalytic material inside particulate matter filters in automotive exhaust gas aftertreatment towards the slurry transport in dredging operations. In this contribution, we focus on the particle-resolved direct numerical simulation (PR-DNS) of the particle-laden flow. Such a simulation combines the standard Eulerian approach to computational fluid dynamics (CFD) with inclusion of particles via a variant of the immersed boundary method (IBM) and tracking of the particles movement using a discrete element method (DEM). Provided the used DEM allows for collisions of arbitrarily shaped particles, PR-DNS is based (almost) entirely on first principles, and as such it is a truly high-fidelity model. The downside of PR-DNS is its immense computational cost. In this work, we focus on three possibilities of alleviating the computational cost of PR-DNS: (i) replacing PR-DNS by PR-LES or PR-RANS, while the latter requires combining IBM with wall functions, (ii) improving efficiency of DEM contact solution via adaptively refined virtual mesh, and (iii) developing a method of model order reduction specifically tailored to PR-DNS of particle-laden flows.
Keywords:
particle-laden flow; CFD-DEM; arbitrarily-shaped particles; finite volume method
Fulltext is available at external website.
Simulating particle-laden flows: from immersed boundaries towards model order reduction
Particle-laden flow is prevalent both in nature and in industry. Its appearance ranges from the trans-port of riverbed sediments towards the magma flow, from the deposition of catalytic material ...
On Reynolds-averaged turbulence modeling with immersed boundary method
Kubíčková, Lucie; Isoz, Martin
2023 - English
The immersed boundary (IB) method is an approach in the computational fluid dynamics in which complex geometry conforming meshes are replaced by simple ones and the true simulated geometry is projected onto the simple mesh by a scalar field and adjustment of governing equations. Such an approach is particularly advantageous in topology optimizations (TO) where it allows for substantial speed-up since a single mesh can be used for all the tested topologies. In our previous work, we linked our custom IB variant, the hybrid fictitious domain-immersed boundary method (HFDIB), with a TO framework and successfully carried out an optimization under laminar flow conditions. However, to allow for optimizations of reallife components, the IB approach needs to be coupled with an affordable turbulence modeling. In this contribution, we focus on extending the HFDIB approach by the possibility to perform Reynolds-averaged simulations (RAS). In particular, we implemented the k − ω turbulence model and wall functions for closure variables and velocity.
Keywords:
immersed boundary; RAS; wall functions; CFD; OpenFOAM
Fulltext is available at external website.
On Reynolds-averaged turbulence modeling with immersed boundary method
The immersed boundary (IB) method is an approach in the computational fluid dynamics in which complex geometry conforming meshes are replaced by simple ones and the true simulated geometry is ...
Finite element modal analysis of a silicone vocal fold filled with fluid
Hájek, P.; Radolf, Vojtěch; Horáček, Jaromír; Švec, J. G.
2023 - English
A three dimensional (3D) finite element (FE) model of a silicone vocal fold (VF) filled with fluid is presented here. The silicone part of the model is based on partial differential equations of the continuum mechanics and consider large deformations. The fluid domain encapsulated in the silicone VF is defined semianalytically as a lumped-element model describing the fluid in hydrostatic conditions. The elongated and pressurized silicone VF was subjected to perturbed modal analysis. Results showed that the choice of the fluid inside the VF substantially influences the natural frequencies. Namely, the water-filling lowers the natural frequencies approximately by half over the air-filling. Besides, the procedure of reverse engineering for obtaining the geometry of the VF from already 3D-printed mold is introduced.
Keywords:
perturbed modal analysis; finite element method; vocal folds; reverse engineering; biomechanics of voice
Fulltext is available at external website.
Finite element modal analysis of a silicone vocal fold filled with fluid
A three dimensional (3D) finite element (FE) model of a silicone vocal fold (VF) filled with fluid is presented here. The silicone part of the model is based on partial differential equations of the ...
Posouzení výpočtové dokumentace zaměřené na hodnocení analýzy dopadu zvýšení výkonu bloků EDU II na vertikální stabilitu a dynamickou odezvu vnitřních částí reaktoru včetně uvažování nehody LOCA DN500
Pták, Svatopluk
2023 - Czech
Tato technická zpráva shrnuje výsledky posouzení výpočtové dokumentace zaměřené na hodnocení analýzy dopadu zvýšení výkonu bloků EDU II v souvislosti s projektem '6729 − Využití projektových rezerv bloků EDU II' na vertikální stabilitu a dynamickou odezvu vnitřních částí reaktoru včetně uvažování nehody LOCA DN500, konkrétně se jedná o posouzení dvou zpráv autorských kolektivů z ÚJV, a. s.: 'M. Klemenc a P. Gál: Analýzy dopadu zvýšení výkonu na dynamické chování VČR při nehodě LOCA DN500, zpráva ÚJV DITI 2301/1242, 12/2020' a M. Švrček a J. Vyčichl: Analýzy dopadu zvýšení výkonu na vertikální stabilitu a vibrační odezvu (vysokocyklovou únavu) VČR, zpráva ÚJV DITI 2301/1307, 08/2021. This technical report summarizes the results of the assessment aimed at evaluation of the impact analysis of the increase in the performance of EDU II units in connection with the project '6729 - Use of design margins of the Dukovany reactor units' on the vertical stability and dynamic response of the reactor internal components, including consideration of the LOCA DN500 event, specifically, it is an assessment of two reports of author collectives from ÚJV, a. s.: M. Klemenc and P. Gál: 'Analyzes of the impact of the power increase on the dynamic behavior of RIC during the LOCA DN500 event, report ÚJV DITI 2301/1242, 12/2020 and M. Švrček a J. Vyčichl: 'Analyzes of the impact of increasing power on vertical stability and vibration response (high-cycle fatigue) of RIC', report ÚJV DITI 2301/1307, 08/2021.
Keywords:
loss coolant accident; dynamic response; primary pipelime of nuclear reactor; internal parts of nuclear reactor
Available at various institutes of the ASCR
Posouzení výpočtové dokumentace zaměřené na hodnocení analýzy dopadu zvýšení výkonu bloků EDU II na vertikální stabilitu a dynamickou odezvu vnitřních částí reaktoru včetně uvažování nehody LOCA DN500
Tato technická zpráva shrnuje výsledky posouzení výpočtové dokumentace zaměřené na hodnocení analýzy dopadu zvýšení výkonu bloků EDU II v souvislosti s projektem '6729 − Využití projektových rezerv ...
Souhrnná zpráva zakázky OZM-LCF-2023: Experimentální hodnocení vlastností oceli 1.4529 z hlediska nízkocyklové únavy
Štefan, Jan; Parma, Slavomír
2023 - Czech
Tato technická zpráva byla zpracována v rámci zakázky „OZM-LCF-2023: Experimentální hodnocení vlastností oceli 1.4529 z hlediska nízkocyklové únavy“. Ve zprávě jsou přehledně zdokumentovány všechny podstatné informace týkající se odborného plnění zakázky počínaje návrhem experimentálního programu, přes protokoly o provedených experimentech až po souhrnné vyhodnocení programu vč. návrhů pro případné rozšíření zakázky a navazující experimentální činnost. This technical report was prepared within the framework of the contract "OZM-LCF-2023: Experimental evaluation of the properties of steel 1.4529 in terms of low cycle fatigue". The report clearly documents all relevant information concerning the technical performance of the contract, starting from the design of the experimental program, through the protocols of the experiments performed, to the summary evaluation of the program, including proposals for possible contract extension and follow-up experimental activities.
Keywords:
material testing; low-cycle fatigue; austenitic stainless steels
Available at various institutes of the ASCR
Souhrnná zpráva zakázky OZM-LCF-2023: Experimentální hodnocení vlastností oceli 1.4529 z hlediska nízkocyklové únavy
Tato technická zpráva byla zpracována v rámci zakázky „OZM-LCF-2023: Experimentální hodnocení vlastností oceli 1.4529 z hlediska nízkocyklové únavy“. Ve zprávě jsou přehledně zdokumentovány všechny ...
Measurements on KR-D-11B Optimized Subsonic Blade Cascade
Šimurda, David; Hála, Jindřich
2023 - English
This report contains results and evaluation of aerodynamic measurements conducted on a subsonic compressor blade cascade.
Keywords:
compressor blade cascade; experiment; subsonic flow; optimized profile
Available at various institutes of the ASCR
Measurements on KR-D-11B Optimized Subsonic Blade Cascade
This report contains results and evaluation of aerodynamic measurements conducted on a subsonic compressor blade cascade.
The design of Bayesian diagnostic expert system Querix and it’s engineering application
Věchet, Stanislav; Krejsa, Jiří; Chen, K.-S.
2023 - English
Expert systems have gained attention over the last two decades as they bring the possibility of using expert knowledge in various control systems. However, it has lost attraction in favor of artificial neural networks in recent years, which is mostly influenced by the availability of data to train neural network models and the availability of various frameworks to achieve fast time-to-market applications for given solutions.
Keywords:
expert system; decision making; advanced diagnostic; autonomous navigation; RPA
Available at various institutes of the ASCR
The design of Bayesian diagnostic expert system Querix and it’s engineering application
Expert systems have gained attention over the last two decades as they bring the possibility of using expert knowledge in various control systems. However, it has lost attraction in favor of ...
Annular Impinging Jets and an Active Control of Hysteretic Effects
Devani, Yogendrasasidhar; Antošová, Zuzana; Trávníček, Zdeněk
2023 - English
An annular impinging air jet with and without flow control was studied experimentally using measurements of the wall pressure and flow velocity by the Pitot probe. To investigate flow control swirling effects, eight synthetic jets were generated from the nozzle center body. The experiments cover Reynolds numbers 4000–10,000 (evaluated from the outer exit diameter of the annular nozzle). For Re<9000, the bistability and hysteresis were identified and two different flow field patterns (A, B) were found under the same boundary conditions. For higher Re>9000, the hysteresis were not found.
Keywords:
annular jet; impinging jet; hysteresis
Available at various institutes of the ASCR
Annular Impinging Jets and an Active Control of Hysteretic Effects
An annular impinging air jet with and without flow control was studied experimentally using measurements of the wall pressure and flow velocity by the Pitot probe. To investigate flow control swirling ...
Souvislost mezi principem nejmenší akce a termodynamickou podmínkou stability
Maršík, František; Trávníček, Zdeněk; Antošová, Zuzana
2023 - English
The extended principle is formulated for a material point (M.P.) X, which has nonzero mass, temperature, and trajectory x(X,t). The Lagrangian of this variation principle is equal to the kinetic energy from which, the internal energy of the material point (which depends on the entropy) and the additional energy caused by the frictional force are subtracted. The relation between the inertial force and the entropy gradient is found and the gravitational force is completely replaced by the entropy gradient. Thanks to the mentioned properties of the total enthalpy, the Thermodynamic criterion of stability of the state of M.P., is formulated.
Keywords:
principle of the least action; thermodynamic stability condition; annular swirl flow
Fulltext is available at external website.
Souvislost mezi principem nejmenší akce a termodynamickou podmínkou stability
The extended principle is formulated for a material point (M.P.) X, which has nonzero mass, temperature, and trajectory x(X,t). The Lagrangian of this variation principle is equal to the kinetic ...
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