No (235)
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235
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The Magnus force coefficient oof the spherical particle moving in liquid
Lukerchenko, Nikolay; Kvurt, Y.; Chára, Zdeněk; Vlasák, Pavel
2006 - English
The Magnus force coefficient was determined from comparison of theoretical and experimental trajectory of rotating spherical particle moving in calm water. Theoretical trajectories of the particle were calculated using the 2D numerical model of the rotating spherical particle moving in liquid and the proper value of the Magnus force coefficient was established from condition of the best fitting of the experimental trajectory by the calculated one. Magnusův odporový koeficient byl určen na základě teoreticky odvozené a experimentálně zjištěné trajektorie kulové částice pohybující se v klidné vodě. Teoretické řešení bylo získáno z 2D numerického modelu pohybu kulovité částice a Magnusův koeficient byl určen ze vzájemné shody teoretické a experimentální trajektorie.
Keywords:
Magnus coefficient
Available at various institutes of the ASCR
The Magnus force coefficient oof the spherical particle moving in liquid
The Magnus force coefficient was determined from comparison of theoretical and experimental trajectory of rotating spherical particle moving in calm water. Theoretical trajectories of the particle ...
Survey of some results on the asymptotic dynamics of weak solutions of the homogeneous Navier-Stokes equations
Skalák, Zdeněk
2006 - English
The main goal of the paper is the presentation of several recent results concerning asymptotic dynamics of weak solutions of the homogeneous Navier-Stokes equations. Hlavním cílem článku je prezentace několika nových výsledků týkajících se asymptotické dynamiky slabých řešení homogeních Navierových-Stokesových rovnic.
Keywords:
Navier-Stokes equations, asymptotic dynamics
Available at various institutes of the ASCR
Survey of some results on the asymptotic dynamics of weak solutions of the homogeneous Navier-Stokes equations
The main goal of the paper is the presentation of several recent results concerning asymptotic dynamics of weak solutions of the homogeneous Navier-Stokes equations....
Simulation of destruction of clays under natural conditions with involvement of heterotropic bakteria in bioforming of Al gels at Podluží (Southern Moravia, Czech Republic)
Ďurďová, Libuše; Štyriaková, I.
2006 - English
In study is experimentally quantified and characterised bioweathering of smectite which was used from mineralogical collections as it is a rich aluminium source of specific aluminium gels forming. Degradation process of silicate mineral, which occurr at the sediment/water interface as was traced and monitored with use of solution chemistry prepared according to Ashby. X- ray analyses and chemical analyses as well as electron microscopy techniques were used. Impact of bacteria Bacillus was determined on mineral surface and leaching of Mg, Si, and Al. By figures from samples from fields are documented stages of Al colloids and precipitated metal pieces forming from weathered rocks and their minerals. Al stayed at mineral surface at destruction place and formed colloids. Temperature increase affected the efficiency of ions extraction from entering material. Ve studii bylo v experimentech kvantifikováno a charakterizováno biologické zvětrávání smektitu, který byl použit z mineralogické sbírky jako bohatý zdroj hliníku pro tvorbu specifických Al gelů. Proces degradace silikátových minerálů, který se vyskytuje na rozhraní sediment/voda byl sledován a monitorován za použití roztoku s chemismem připraveným podle Ashbyho. RTG analýzy a chemické analýzy stejně jako techniky elektronové mikroskopie byly použity. Byl určen vliv bakterie Bacillus na minerální povrch a louhování Mg, Si a Al. Pomocí fotografií vzorků z terénu byla doložena stadia tvorby Al koloidů a precipitátů ze zvětralých hornin a jejich minerálů. Hliník zůstával na minerálním povrchu v místě destrukce a tvořil koloidy. Zvýšení teploty ovlivnilo účinnost uvolňování iontů ze vstupního materálu.
Keywords:
bioweathering; smectite; Al colloids; bacteria Bacillus; TEM - documentation of destruction process
Available at various institutes of the ASCR
Simulation of destruction of clays under natural conditions with involvement of heterotropic bakteria in bioforming of Al gels at Podluží (Southern Moravia, Czech Republic)
In study is experimentally quantified and characterised bioweathering of smectite which was used from mineralogical collections as it is a rich aluminium source of specific aluminium gels forming. ...
New ideas in technology for desulphatation
Ďurďová, Libuše
2006 - English
Among technologies for desulphatation of AMD and wastes waters there is present the whole scale of technological applications of physical, chemical and microbiological processes. Among positive research results there are important patents of IEE TUO Ostrava with ecologically advantageous methods of precipitation of sulphates from AMD. Some new ideas on barriers for treatment of AMD waters presented can be applied for waste water cleaning and also for in situ improvement of ground water chemistry at vicinity of wellfield with sulphate concentration increasing above 300-400 mg.l-1. Mezi technologiemi pro desulfataci AMD a odpadních vod je celá škála technologických aplikací fyzikálnách, chemických a mikrobiologických procesů. Mezi pozitivními výsledky jsou důležité patenty of IEE TUO Ostrava s ekologicky šetrnými vyhodnými methodami srážení síranů z AMD vod. Některé nové prezentované ideje o bariérách pro čištění AMD vod mohou být aplikovány na čištění odpadních vod a také pro r in situ zlepšení chemismu podzemní vody v sousedství jímacího území s koncentrací sulfátů nad 300-400 mg.l-1.
Keywords:
AMD; desulphatation; organic substrate; biotechnologies; barriers; in situ application
Available at various institutes of the ASCR
New ideas in technology for desulphatation
Among technologies for desulphatation of AMD and wastes waters there is present the whole scale of technological applications of physical, chemical and microbiological processes. Among positive ...
Simulation of flow past circular cylinder for wide range of subritical Reynolds numbers
Hoření, Bohumír; Chára, Zdeněk
2006 - English
Numerical simulation of the flow past a circular cylinder for Reynolds numbers going from 20 to 200000 is presented. The numerical simulations were performed with help of discontinuous Galerkin method. This method offers a compact formulation ensuring a useful method to obtain a high accuracy solution especially for unstructured grids. V příspěvku jsou ukázány numerické simulace proudění kolem kruhového válce pro široký rozsah Reynoldsových čísel od 20 do 200000. Řešení je založeno diskuntinuální Galerkinově metodě, což umožňuje získat řešení s velkou přesností zvláště při použití nestrukturované výpočetní sítě.
Keywords:
Galerkin method
Available at various institutes of the ASCR
Simulation of flow past circular cylinder for wide range of subritical Reynolds numbers
Numerical simulation of the flow past a circular cylinder for Reynolds numbers going from 20 to 200000 is presented. The numerical simulations were performed with help of discontinuous Galerkin ...
20th Symposium on Anemometry - Proceedings
2006 - English
Proceedings of 20th Symposium on Anemometry. The conference was oriented on the experimental techniques applied in fluid mechanics.
Keywords:
fluid mechanics; conference
Available at various institutes of the ASCR
20th Symposium on Anemometry - Proceedings
Proceedings of 20th Symposium on Anemometry. The conference was oriented on the experimental techniques applied in fluid mechanics.
Measurement of the velocity field in a ribbed channel
Chára, Zdeněk
2005 - English
The contribution deals with an experimental investigation of the turbulent along a ribbed channel bottom. The main goal is an application of ultrasound velocity profile technique for measurement of the turbulent flow characteristics in complex geometries. Four configurations of the ribbed surfaces were tested with fixed ribs of square cross section and variable groove widths. The experiments were performed in a water channel.
Keywords:
ribbed channel; velocity field; turbulent flow
Available at various institutes of the ASCR
Measurement of the velocity field in a ribbed channel
The contribution deals with an experimental investigation of the turbulent along a ribbed channel bottom. The main goal is an application of ultrasound velocity profile technique for measurement of ...
Composition of sediments, Al-Si gelatine and precipitates related to the occurrence of elemental Al, Si, Fe from monitoring borewells by wellfield Podluží
Ďurďová, Libuše
2005 - English
Occurrence of increased sulphate concentration in groundwater of the Quaternary sediments in the floodplane of the Morava river watershed is related to many specific features in hydrogeology, hydrochemistry, microbiology, geochemistry, exploitation of water resources, climatic conditions, and technical equipment of boreholes. One of the concsequences is genesis of 2-4 m thick layer of sediments at the bottom of moitoring boreholes Vis with mineral precipitates, sludge, Al and Si gelatines, precipitates of elemental forms of Al, Si and Fe. There were found also colloids of FeS2 composition and minerals goethite, magnetite, lepidocrocite, pyrite, greygite under extreme oxido-redox conditions. Výskyt zvýšené koncentrace síranů v podzemní vodě kvartérních sedimentů v údolní nivě v povodí řeky Moravy má vztah k mnoha specifickým rysům z oblasti hydrogeologie, hydrochemie, microbiologie, geochemie zkoumaného území, k exploataci zdejších vodních zdrojů, ke klimatickým podmínkám a k technickému vybavení vrtů. Jeden z důsledků je tvorba až 2-4 m mocné vrstvy sedimentů na dně monitorovacích vrtů VIS s precipitáty minerálů, kaly, Al a Si gely, s precipitáty elementálních forem Al, Si a Fe. Byly zde nalezeny také koloidy o složení FeS2 a minerály goethit, magnetit, lepidokrokit, pyrit, greygit v extrémních oxidačně redukčních podmínkách.
Keywords:
high sulphate concentration; Al and Si gelatines; sediment
Available at various institutes of the ASCR
Composition of sediments, Al-Si gelatine and precipitates related to the occurrence of elemental Al, Si, Fe from monitoring borewells by wellfield Podluží
Occurrence of increased sulphate concentration in groundwater of the Quaternary sediments in the floodplane of the Morava river watershed is related to many specific features in hydrogeology, ...
Dominant flow features of twin jets in crossflow
Kolář, Václav; Savory, E.
2005 - English
A survey of the recent studies of "twin jets in crossflow" (TJICF) by the present authors is carried out and extended in terms of results of the velocity-field analysis based on decomposition techniques. Similarities and differences between the dominant mean-flow vortical features, vorticity and circulation associated with three basic ground arrangements (tandem, side-by-side and oblique arrangements) are examined, and the comparison with the single jet case is carried out as well.
Keywords:
jets in crossflow; vortical structures; vortex characteristics
Available at various institutes of the ASCR
Dominant flow features of twin jets in crossflow
A survey of the recent studies of "twin jets in crossflow" (TJICF) by the present authors is carried out and extended in terms of results of the velocity-field analysis based on decomposition ...
Modelling the hydrodynamics and water quality of the Vltava river reservoir cascade
Růžička, Martin; Hejzlar, Josef; Jarošík, Jiří
2005 - English
Mathematical modelling is an efficient tool for evaluation of impacts of human activities and environmental changes on water quality in rivers and reservoirs. This contribution describes simulations of water quality in the Vltava River reservoir system, namely cascade of reservoirs Hněvkovice, Orlík, Kamýk, Slapy, Štěchovice, and Vrané. The two-dimensional water quality model CE-QUAL-W2 was used for this task over years 2000 to 2003. Sensitivity analysis, calibration, and evaluation of the model were done. The model gave good results in particular for hydrodynamics, water temperature, and conservative constituents because of good quality of available hydrological and meteorological input data. The accuracy of results was strongly depended on the quality of input data and sampling frequency. Minor problems occurred in water quality simulations based on monthly input data in periods with fluctuating discharges.
Keywords:
water quality; mathematical modeling; reservoir system
Available at various institutes of the ASCR
Modelling the hydrodynamics and water quality of the Vltava river reservoir cascade
Mathematical modelling is an efficient tool for evaluation of impacts of human activities and environmental changes on water quality in rivers and reservoirs. This contribution describes simulations ...
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