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3D mathematical model of spherical particle saltatory movement in open channel with rough bed
Lukerchenko, Nikolay; Chára, Zdeněk; Vlasák, Pavel
2003 - English
One of the main modes of bed load transport is saltation when particles hop up from the bed and follow ballistic-like trajectories. Mathematical models of saltation are mostly two-dimensional although the particle motion is actually three-dimensional. The aim of the present study is development of the 3D mathematical model of solid particle saltatory motion over rouhg bed in an open channel.
Keywords:
3D mathematical model; open channel; rough bed
Available in digital repository of the ASCR
3D mathematical model of spherical particle saltatory movement in open channel with rough bed
One of the main modes of bed load transport is saltation when particles hop up from the bed and follow ballistic-like trajectories. Mathematical models of saltation are mostly two-dimensional although ...
Effect of the heat transfer on the laminar flow in the entrance region of a circular tube
Mík, Václav
2003 - English
An analytical-numerical model of the velocity and temperature field was created, whose parameters are expressed as functions of the thickness of the hydrodynamic and thermal boundary layers. This model converts the set of specific partial differential equations to a set of ordinary differential equations that are always valid in one of three regions into which the entrance region is divided by above mentioned boundary layers.
Keywords:
heat transfer; laminar flow; circular tube
Available in digital repository of the ASCR
Effect of the heat transfer on the laminar flow in the entrance region of a circular tube
An analytical-numerical model of the velocity and temperature field was created, whose parameters are expressed as functions of the thickness of the hydrodynamic and thermal boundary layers. This ...
Experimental assignment of total drag coefficients of bodies embedded in a free surface stream
Chára, Zdeněk; Vlasák, Pavel
2003 - English
The paper deals with an experimental determination of total drag coefficients of bodies of various shapes embedded in a free stream flow. The shapes of bodies were chosen by such way that they could model simple bridge constructions or culverts. The bodies were mostly overflowed. The drag coefficients can be used to calculate an afflux of the embedded bodies.
Keywords:
total drag coefficients; free surface stream
Available in digital repository of the ASCR
Experimental assignment of total drag coefficients of bodies embedded in a free surface stream
The paper deals with an experimental determination of total drag coefficients of bodies of various shapes embedded in a free stream flow. The shapes of bodies were chosen by such way that they could ...
Non-Newtonian liquids : determination of a value of viscosity characterising the initial newtonian plateau
David, Jiří; Filip, Petr
2003 - English
The present contribution indicates that precisely the same situation - as with the determination of the so-called yield stress of viscoplastic materials - concerns also the value of viscosity describing the initial Newtonian plateau. It is shown that the determination of this value from the experimental data is not unique, significantly subjects to the range of measured parameters, and the proper determination of the precise value is very questionable.
Keywords:
Non-Newtoninan liquids; viscosity characterising; initial Newtonian plateau
Available in digital repository of the ASCR
Non-Newtonian liquids : determination of a value of viscosity characterising the initial newtonian plateau
The present contribution indicates that precisely the same situation - as with the determination of the so-called yield stress of viscoplastic materials - concerns also the value of viscosity ...
On non-monotonous behaviour of shear-viscosity function
David, Jiří; Filip, Petr
2002 - English
The aim of this contribution is to propose a new phenomenological model enabling description of non-monotonicity of shear-viscosity function for rheologically complex fluids. The applicability of this model is discussed with the emphasis on the number of model parameters and experimentally examined.
Keywords:
phenomenological models; apparent viscosity; shear thinning
Available in digital repository of the ASCR
On non-monotonous behaviour of shear-viscosity function
The aim of this contribution is to propose a new phenomenological model enabling description of non-monotonicity of shear-viscosity function for rheologically complex fluids. The applicability of this ...
Hydraulics of overflowed bridge
Chára, Zdeněk; Vlasák, Pavel
2002 - English
The paper deals with an open channel flow around model of a bridge when the water depth is higher than height of the bridge opening. Both the pressured flow through bridge opening and free surgace flow over the model were studied. For both cases discharge coefficients were determined and for overflowed model also the velocity profiles were measured to evaluate the ratio of discharges going below and over the bridge model.
Keywords:
open channel flow; ultrasound velocity measurement; discharge coefficient
Available in digital repository of the ASCR
Hydraulics of overflowed bridge
The paper deals with an open channel flow around model of a bridge when the water depth is higher than height of the bridge opening. Both the pressured flow through bridge opening and free surgace ...
Thinning of kaolin slurry
Vlasák, Pavel; Chára, Zdeněk; Konfršt, Jiří
2002 - English
After mixing kaolin with water attractive and repulsive forces between kaolin particles initiate process of coagulation and peptisation, respectively. The coagulation process in the kaolin slurry gives rise to voluminous aggregates of kaolin particles, where a great deal of water is fixed.
Keywords:
Rheology of suspension; drag reduction; kaolin slurry
Available in digital repository of the ASCR
Thinning of kaolin slurry
After mixing kaolin with water attractive and repulsive forces between kaolin particles initiate process of coagulation and peptisation, respectively. The coagulation process in the kaolin slurry ...
Axisymmetric wall and liquid jets with swirl
Kolář, Václav; Filip, Petr
2001 - English
The contribution deals with the global characteristics of wall and liquid jets with swirl on bodies of revolution.
Keywords:
wall jets; similarity solutions
Available in digital repository of the ASCR
Axisymmetric wall and liquid jets with swirl
The contribution deals with the global characteristics of wall and liquid jets with swirl on bodies of revolution.
Application of hydraulically filled bags in flood protection
Vlasák, Pavel; Chára, Zdeněk; Vatolík, K.; Pařenica, J.
2001 - English
The paper deals with introducing and application of equipment and technology being suitable for prompt and operative building of new and/or improving the contemporary levees and elimination of local impact of water erosion or scour during flood events. The proposed solution is based on utilisation of special large-voluminous bags, filled hydraulically by a mixture of water and environmentally acceptable loose material.
Keywords:
flood protection; large-voluminous bags; hydraulic filling
Available in digital repository of the ASCR
Application of hydraulically filled bags in flood protection
The paper deals with introducing and application of equipment and technology being suitable for prompt and operative building of new and/or improving the contemporary levees and elimination of local ...
Influence of bridge structures on river flow
Chára, Zdeněk; Vlasák, Pavel
2001 - English
The paper deals with an open channel flow over model of a bridge when whole discharge is going through the model opening and the upstream water level is at the same level as upper deck of the model.
Keywords:
channel flow; bridge hydraulics
Available in digital repository of the ASCR
Influence of bridge structures on river flow
The paper deals with an open channel flow over model of a bridge when whole discharge is going through the model opening and the upstream water level is at the same level as upper deck of the model.
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