Projects / Programmes
Development of a computer-aided visualization method for the diagnostics of velocity fields in hydrodynamic systems
| Code |
Science |
Field |
Subfield |
| 2.05.05 |
Engineering sciences and technologies |
Mechanics |
Fluid mechanics |
| Code |
Science |
Field |
| P240 |
Natural sciences and mathematics |
Gases, fluid dynamics, plasmas |
| Code |
Science |
Field |
| 2.03 |
Engineering and Technology |
Mechanical engineering |
Visualization, fluids, velocity field, hydrodynamic systems
Researchers (25)
Organisations (4)
Abstract
Increasing demand of EU and therefore of Slovenia to raise the portion of renewable- and environmental friendly energy sources stimulates more intensive hydroenergy usage from water sources and consequential construction of new hydropower objects. Such activities often change the conditions for water flow and its surroundings, which should be properly protected or some suitable measures should be undertaken in order to mitigate the adverse consequences particularly in the case of high-water flows. Special hydrodynamic systems are used for protection of objects and river surroundings. These systems such as side weirs, barriers, etc. cater for the appropriate discharge of high flows from rivers in order to prevent inundations, which can have negative consequences on the environment, objects and humans. In the presence of more and more frequent uncontrolled floods and inundations in Slovenia and EU in recent years, there is an increasing need for efficient water discharge at appropriate places along rivers. The fundamental part of this need is presented in optimization of hydrodynamic systems, which enable suitable discharge of superfluous water in the case when river level rises too high. Optimization and design of suitable hydrodynamic systems requires the knowledge of kinematic properties of the flow in the system, up- and downstream of the system as well as in the area of inundation plains, where the superfluous water is discharged.
We plan to develop a contactless, computer-aided visualization based method for measurements of velocity field in hydrodynamic systems of surface flows in order to determine relations between influential parameters, which are needed for optimization of such systems. The method will be based on physical relations rather than on time- and spatial correlations. Concentration of passive pollutant will be monitored in the water flow. Changes of pollutant concentration will be determined by the use of modern mathematical-computational geometric structures and numerical methods. The proposed method will be applied on model hydrodynamic systems. Results of model measurements will be physical laws or phenomenological relations, which will interconnect the influential parameters of the hydrodynamic system and its efficiency. The resulting phenomenological relations on experimental model systems will be used to predict inundation processes in natural environment.
Numerical simulations of free-surface flows will be carried out simultaneously for the same model systems using the commercial numerical code. Visualization method will be of great importance for verification of extant commercial numerical models of flow fields on different spatial- and time scales. Particular expressions in Navier-Stokes equations are empirically modelled in numerical codes and often do not poses a physical background. Experimental visualization method will be based on relations that origin from advection-diffusion equation. Therefore, particular expressions in Navier-Stokes equations will be calculated by the visualization method via suitable mathematical procedures. The knowledge of these expressions will enhance the predictions of numerical simulations. On the other hand, such an approach will enable to establish important missing links between the changes in flow structures and the changes in values of these expressions.
For the purposes of quick dissemination we plan to present our work on the project in at least 5 scientific and technical conferences. Additionally, the results are planned to be published in at least 10 peer-reviewed scientific papers.
Partners Faculty of Mechanical Engineering (FME) and Faculty of Civil and Geodetic Engineering (FCGE) will carry out the experimental part of the project. Institute for mathematics, Physics and Mechanics (IMPM) will prepare the appropriate software for the visualization method. Numerical simulations and modifications of extant numerical codes will be carried out at Turboinštit
Significance for science
Optimization of hydrodynamic systems (discharges, side weirs, settling tanks, etc.) through kinematic properties at different geometric shapes and operating conditions is an issue that becomes increasingly important (hydropower objects, floods, wastewater treatment, etc.), but is still in its basic phases of development. Most studies from this field of science are focused on flow properties in combined cross-sections (riverbed and the corresponding inundation plane). Recent studies are mainly focused on simple determination of flow rates only. The consequence of ignoring the kinematic properties of the flow is lower efficiency of hydrodynamic systems, which in turn can cause adverse effects on people and environment due to poorly regulated floods and inundations. On the other hand, undetermined velocity field of the flow is mainly the consequence of inappropriate measurement methods, which are used in experiments in non-industrial environments (experiments on models) or in real surface flows and their corresponding objects. Readily available measurement methods for quantification of kinematic properties in hydrodynamic systems usually enable only marginal detection of velocity field. Limitations in the use of extant measurement methods are the consequence of their complexity, inability to capture the whole velocity field in a selected area at once, their physical presence in the flow (probes) and/or their high price. The developed method for quantification of velocity fields in hydrodynamic systems is based on computer-aided visualization. This approach is recognized in the last decade as a highly perspective example of advanced technology. Together with the fast development of appropriate and increasingly available hardware (PCs, high-speed cameras), the proposed method represents a useful tool in the field of free-surface water flows and beyond. Ease of handling, quick application, low number of components, and wide spectrum of usage make the proposed measurement method particularly attractive from the exploitation view. The other important property of the method developed in the project is that it is based upon the application of physical laws that govern fluid dynamics and mass transfer rather than upon correlation between images like other visualization methods. Together with the ability of monitoring the flow conditions qualitatively and quantitatively (i.e. velocity and pressure fields), the method can provide the fundamental study of mechanisms that govern particular phenomenon or flow structure. This is accomplished through conservation laws such as Navier-Stokes equations. Such an approach is innovative not only in the field of free-surface flows, but also in the field of fluid dynamics as a whole. In this way, the results of the project can be applied on similar fields of science, such as the optimization of experimental methods in mechanics of continuum and the optimization of numerical methods in fluid dynamics.
Significance for the country
Hydropower objects require the flow rate that is within certain limits and can therefore influence the inundation of the environment. The amount of such objects along rivers in Slovenia is increasing in order to ensure the required portion of renewable energy sources. Apart from that, there is an increasing number of floods and inundations in recent years due to climate changes that threaten human lives, material property and influence the changes in river environments. Therefore, there is a need to optimize and to increase the efficiency of hydrodynamic systems that enable controlled discharge of high river flows without adverse consequences on humans and environment. A typical example of such a need is reflected through practical examples on national level, which implies the more efficient planning of hydropower utilization of Sava river between Krško and the state border with Croatia. This is known as a highly sensitive area with a nuclear powerplant and wide inundation plains in the vicinity of the state border. A key factor here is the activation of available retention areas in order to discharge appropriately a part of high river flow. This will enable the anti-flood protection for the nuclear powerplant Krško, for Čatež ob Savi and for Čatež spa. At the same time, the requirement for decreasing the front of high-water wave of the river profile at the state border will be fulfilled. The project involves the concern for human environment, life standard of the habitants, and decrease in energy consumption. The drawback of water power utilization (i.e. hydroenergy) is often connected with environmental and ecological complications, limited life expectancy and human migrations. Extensive utilization of hydroenergy and climate changes in recent years together with inappropriate designed hydrodynamic objects and systems for discharge of high-water flows from rivers cause inundations. These have adverse effects on nearby living people, material property, and environment. Apart from that, there is a persistent problem of wastewater treatment in specialised hydrodynamic systems. Research activities, proposed in the project, are therefore expected to have a significant impact towards general environment protection and prevention of catastrophes that are caused by above mentioned factors. In this way, the number of potential human victims as well as the costs of intervention and removal of expected consequences can be significantly lowered. The proposed visualization method for quantification of velocity fields on hydrodynamic systems, which will enable the measurement of velocity field of fluid flow through the concentration field of pollutant, represents a modern contactless measurement method. It is based on the application oif physical laws of fluid dynamics and mass transfer. The proposed method from a technical point of view represents a high potential on the national level (an example of domestic high technology). One of the advantages of the proposed method is the reduced amount of time needed for measurement execution, which is an important economic factor that substantially influences the costs of a particular R&D project. The other socio-economic influences of the proposed project will be reflected mainly in reduction of costs, which otherwise occur in hybrid physical model measurements. Namely, phenomenological models of relations between influential parameters in hydrodynamic systems will replace the additional measurements on the physical models of real systems. The same goes for verified and selected numerical models, which will be able to replace costly experimental work on physical models used mainly in design of new hydrodynamic objects. The proposed project therefore not only raises the science and technology levels of involved partners, but also (through the results of the executed dissemination) of the local population and its perception.
Most important scientific results
Annual report
2011,
2012,
2013,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2011,
2012,
2013,
final report,
complete report on dLib.si
