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Projects / Programmes source: ARIS

Intergration of the SPH method with conventional numerical methods and boundary conditions for simulation of water and sediment dynamics

Research activity

Code Science Field Subfield
2.20.00  Engineering sciences and technologies  Hydrology   

Code Science Field
T220  Technological sciences  Civil engineering, hydraulic engineering, offshore technology, soil mechanics 

Code Science Field
2.07  Engineering and Technology  Environmental engineering  
Keywords
Smoothed Particle Hydrodynamic, Tis Isat code, SPHysics code, dam-break waves, free surface flow, pressure flow, multi-phase flow, sediment transport
Evaluation (rules)
source: COBISS
Researchers (12)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  21237  PhD Tom Bajcar  Process engineering  Researcher  2014  194 
2.  03923  PhD Anton Bergant  Process engineering  Researcher  2011 - 2014  392 
3.  08247  PhD Matjaž Četina  Hydrology  Head  2011 - 2014  590 
4.  30658  PhD Elvira Džebo  Hydrology  Junior researcher  2011 - 2013  27 
5.  12008  MSc Matjaž Ivačič  Computer science and informatics  Researcher  2012 - 2013  57 
6.  14111  PhD Mario Krzyk  Hydrology  Researcher  2011 - 2014  425 
7.  18638  PhD Gregor Petkovšek  Hydrology  Researcher  2011  105 
8.  28342  PhD Vanja Ramšak  Hydrology  Junior researcher  2011 - 2013  16 
9.  25480  PhD Nataša Sirnik  Mechanics  Researcher  2012 - 2013  26 
10.  14877  PhD Alenka Šajn Slak  Control and care of the environment  Researcher  2011 - 2014  129 
11.  11277  PhD Andrej Širca  Civil engineering  Researcher  2011 - 2013  276 
12.  12068  PhD Dušan Žagar  Mechanics  Researcher  2011 - 2014  770 
Organisations (2)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0792  University of Ljubljana, Faculty of Civil and Geodetic Engineering  Ljubljana  1626981  25,723 
2.  2836  Litostroj Power, a company for design, power plant engineering and manufacture of power generation and industrial equipment Ltd.  Ljubljana  2172836  473 
Abstract
Numerical simulations of hydrodynamic phenomena and sediment transport are lately increasingly being simulated using meshless particle methods where the computing elements are mass particles. The relations between them change with time, which enables calculations of larger discontinuities and sudden changes in the fluid. This does away with some of the problems that appear in grid-based models (e.g. numeric diffusion) and also excludes the necessity of generating the grid. SPH (Smoothed Particle Hydrodynamics) is one of the oldest meshless methods. Boundary conditions represent a special challenge in modelling with particle-based methods. Even modelling solid boundaries is not self-evident, as is the case with the Eulerian methods. Research on the influence of bottom roughness and objects on flood wave propagation is scarce. Modelling water-permeable boundary conditions is very demanding. A further challenge in simulating real phenomena is computational time, which can be decreased by coupling with computationally less demanding models. This option is applied when only a part of the domain is subject to rapid changes of the velocity field and surface. This happens at dam outlets, in the vicinity of which the flow is distinctly multidimensional and non-stationary and the surface is poorly defined. Below the dissipation structures or in reservoirs, however, the flow of water and sediments can be satisfactorily described with other models (e.g. two-dimensional SPH-based models or even simpler one-dimensional Eulerian models). The main aim of the proposed project is to upgrade and extend the existing SPH model Tis Isat, which was developed by the project group, in order to take into account: 1) different types of bottom roughness, 2) water- and sediment-permeable boundary conditions, 3) coupling between models, i.e. 3a) between the 2D and 3D versions of Tis Isat, 3b) between models of different resolutions (model nesting), 3c) with conventional models. This would provide us with a tool that could be used in practice for demanding simulations regarding planning and operation of hydroenergy structures. By coupling models, we could simulate the flow of water and sediments with the accuracy that is required in specific parts of the domain. Greater precision would be used in the areas of outflows, dissipation structures, etc. and less precise methods would be applied in the reservoir. Research of bottom and wall roughness would contribute to more accurate simulations of surge front propagation in case of dam breaks. Since the method is still relatively new, its development can greatly contribute to theoretical and practical knowledge on hydrodynamic and environmental problems. On the scientific level, the improvements of the boundary conditions will be a significant contribution. Particularly the sediment-permeable boundary condition is as yet completely unexplored. Coupling models of different dimensionalities is also an original approach never used before. Both this approach and coupling with other models represent a significant decrease of the computation time of the SPH simulations.  This is especially important in practical use on relatively large areas (reservoirs and flooded areas at potential dam breaks). With the suggested improvements, it will be also possible to relatively precisely simulate pollutants. This offers a wide variety of possible publications and inclusion in the teaching process. The development of new boundary conditions and coupling of models, as well as concurrent decrease of the computation time, represent a challenge on the global scale to all SPH researchers. The planned collaboration with a small business (CGS plus, d.o.o) and an internationally acknowledged organisation in the area of hydraulic machinery engineering (Litostroj Power), ensures efficient knowledge transfer between the collaborators.  The method is also directly linked to the priority tasks of environment protection and energy saving.
Significance for science
Although Euler’s methods are typically used for free surface flow simulations, new Lagrangian method has become increasingly popular. One of such Lagrangian method is Smoothed Particle Hydrodynamics (SPH). Method SPH is still in a stage of research and has been constantly improved and developed. Research and simulations of a dam – break waves and modelling of sediment transport using SPH represent a major challenge for all SPH researches and help us to better understand hydraulic phenomena. SPH is a relatively young method, so the SPH method has been constantly improved and developed. Our research team has developed own SPH model Tis Isat. Model has been updated and developed over the entire project period. Tis Isat is the first SPH model, developed in Slovenia. Model, updated with new boundary conditions, represents an important achievement in the international scientific community. One of the main disadvantages of the SPH method is very long computational times. Our research team has developed two interfaces, one for coupling models with different dimensionalities and other for coupling models with different resolutions. For simulating water flow in the channel with an expansion, computational time was significantly decreased by using interfaces. As far as we know this is the first suggested approach for coupling SPH models of different dimensionalities and was well accepted by the association of SPHERIC, which member is also our research group. On the 7th International SPH Workshop, organized by the association of SPHERIC, the new approach for coupling SPH models of different dimensionalities was presented. The same technique was also described in an original research article, published in the SCI Journal of Mechanical Engineering. Simultaneous simulations of water flow dynamics and sediment transport are subject of numerous researches and studies. This research issue represents significant contributions to science. Our SPH model Tis Isat was updated with new permeable boundary condition. Such boundary condition allows us to simulate sediment flushing and deposition. A new interface for calculating shear stresses in torrential watershed using SPH method was also developed. This research represents the useful scientific contribution, because only a few equations for calculating shear stresses using the SPH method in natural torrential watershed, characterised by steep bottom slopes and highly irregular geometries, have been developed so far.
Significance for the country
Although the SPH method is relatively new, different hydraulic and environmental problems can be simulated. Updated SPH model Tis Isat is a very suitable tool for Slovenian water – engineering community, because it can help us to better understand hydrodynamic phenomena and sediment transport and better predict flood areas. Model is extremely useful for dam – break wave simulations generated by the collapse of dams. In general, results of dam –break simulations will be used to improve flood protection in flood risk areas, where dam – break waves can cause a lot of material damage and can endanger human lives. For hydropower plants management also sediment transport needs to be simulated (especially in hydropower plant reservoirs). Our SPH model was designed to simulate also such phenomena. Good cooperation with co-financers enables good exchange of information from the University to the practice. Exchange of experience and knowledge between educational and industrial organisations (co-financers) is very important, so we can get information about practical examples and consequently we can calibrate our own models. Calibrated and verified model is undoubtedly good tool for simulating the hydroelectric power plant operation. Our research group is the first Slovenian member of the SPHERIC society, so we can cooperate with top researches in the field of the SPH method. Cooperation on the workshops and conferences, organised by the SPHERIC society, absolutely well impact on our promotion. The presentation of our achievements in the presence of top scientists in the field increased the recognisability of our scientific work and allows us to cooperate with other leading organisations dealing with the development of SPH method.
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
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