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Nilsson, D. A., Andersson, A. G., Larsson, I. S., Andersson, R. & Billstein, M. (2025). Three-Dimensional Particle Tracking Velocimetry Investigation of Flow Dynamics Around Simplified Stones at Low Submergence: Implications for Instream Habitat. Water, 17(2), Article ID 217.
Åpne denne publikasjonen i ny fane eller vindu >>Three-Dimensional Particle Tracking Velocimetry Investigation of Flow Dynamics Around Simplified Stones at Low Submergence: Implications for Instream Habitat
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2025 (engelsk)Inngår i: Water, E-ISSN 2073-4441, Vol. 17, nr 2, artikkel-id 217Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Shallow waterways such as rapids, tributaries and smaller streams can have important ecological functions in both free-flowing and regulated rivers. As more intermittent renewable energy is introduced to the energy system to reduce CO2 emissions, the operational conditions of hydropower plants are changing. This implies various flow scenarios that can lead to more locations with shallow depths and larger variations in water levels and velocities, resulting in increased impact on the riverine ecosystem. Accurate predictions of these impacts require an understanding of the flow dynamics near large roughness elements such as boulders or trees in shallow river regions. This study uniquely investigates the effect of relative submergence, i.e., water depth relative to boulder size, on the flow field, turbulence, and potential fish habitats around idealized stone shapes (hemispheres) in shallow open channel flow using time-resolved 3D particle tracking velocimetry. The results indicate that varying relative submergence significantly affects recirculation zones, velocity and vorticity distribution, as well as turbulent kinetic energy. Notably, larger regions of lower velocity downstream of the roughness elements were generated at lower submergences, which might be favorable for fish energy conservation. Valuable insights into ecohydraulic engineering and habitat restoration in shallow waterways can be gained by understanding the fundamental flow mechanisms at low submergence for the flow around large roughness elements.

sted, utgiver, år, opplag, sider
MDPI, 2025
Emneord
volumetric PTV, low submergence, shallow flow, simplified stones, fish habitat
HSV kategori
Forskningsprogram
Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-111302 (URN)10.3390/w17020217 (DOI)
Prosjekter
Swedish Centre for Sustainable Hydropower-SVC
Merknad

Validerad;2025;Nivå 2;2025-01-16 (hanlid);

Funder: Swedish Centre for Sustainable Hydropower - SVC

Full text license: CC BY 4.0

Tilgjengelig fra: 2025-01-16 Laget: 2025-01-16 Sist oppdatert: 2025-01-16bibliografisk kontrollert
Östman, M., Larsson, S., Marjavaara, D. & Normann, F. (2024). Control of hydrogen jet mixing through use of coaxial air jet. In: ICJWSF 2024 Proceedings: . Paper presented at The 8th International Conference on Jets, Wakes and Separated Flows, ICJWSF-2024, September 23-25, 2024, Florence, Italy. ICJWSF, Article ID 73.
Åpne denne publikasjonen i ny fane eller vindu >>Control of hydrogen jet mixing through use of coaxial air jet
2024 (engelsk)Inngår i: ICJWSF 2024 Proceedings, ICJWSF , 2024, artikkel-id 73Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

In the process of indurating iron ore pellets, current grate-kiln plants use a coal-fired flame inside a rotary kiln, which results in the formation of CO2 emissions. One alternative is to exchange coal for hydrogen as a fuel to reduce these emissions. In doing so, the mixing characteristics of fuel and secondary process air necessary for the combustion changes. To control the mixing, a coaxial jet can be used. The hydrogen fuel is injected through a central jet, surrounded by an annular jet from which air emanates. The aim is to investigate the effect of the momentum flow ratio between the outer and inner jet, Mjet, on the mixing. Steady-state simulations are performed in Ansys Fluent using a Reynolds-Stress turbulence model. Results show that changing Mjet offers the possibility to control the mixing of the hydrogen jet with the secondary air, thus affecting the length and spread of the jet.

sted, utgiver, år, opplag, sider
ICJWSF, 2024
Emneord
CFD, coaxial jet, mixing, hydrogen jet
HSV kategori
Forskningsprogram
Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-110711 (URN)
Konferanse
The 8th International Conference on Jets, Wakes and Separated Flows, ICJWSF-2024, September 23-25, 2024, Florence, Italy
Prosjekter
Fossil-free combustion in grate-kiln pelletizing plants using co-jet burner
Forskningsfinansiär
Vinnova, 2021-04710Swedish Research Council FormasSwedish Energy Agency
Merknad

Funder: Swedish Mining Innovation

Tilgjengelig fra: 2024-11-13 Laget: 2024-11-13 Sist oppdatert: 2025-02-09bibliografisk kontrollert
Östman, N. M., Larsson, I. A., Lundström, T. S., Marjavaara, D. & Normann, F. (2024). Effect of momentum flow ratio on entrainment of a confined coaxial jet in a co-flow. Engineering Applications of Computational Fluid Mechanics, 18(1), Article ID 2374977.
Åpne denne publikasjonen i ny fane eller vindu >>Effect of momentum flow ratio on entrainment of a confined coaxial jet in a co-flow
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2024 (engelsk)Inngår i: Engineering Applications of Computational Fluid Mechanics, ISSN 1994-2060, E-ISSN 1997-003X, Vol. 18, nr 1, artikkel-id 2374977Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Iron ore pellet production processes produce large amounts of CO2 emissions when burning fossil fuels. One example is the grate-kiln process, where normally a coal flame is used to indurate pellets. To mitigate the emissions, coal used in rotary kilns can be replaced with for example hydrogen. However, the fuel is mixed with secondary process air, and replacing a solid fuel with a gaseous one changes the mixing characteristics. This demands different means of injecting the fuel. A coaxial jet can be used to control the mixing of fuel and secondary air, as well as the flow field. The aim is to control the mixing of hydrogen and secondary air to achieve a hydrogen flame that is similar to the reference coal flame. This study numerically investigates different coaxial jet configurations. Steady-state simulations of a simplified model of the real kiln are performed using a Reynolds Stress turbulence model. Results show that decreasing the momentum flow ratio between the outer and inner jet, 𝑀jet, to a certain value delays the spread of the hydrogen jet and thus gives a longer jet. Further decreasing this ratio gives an even longer jet, but has the side effect of producing recirculation of hydrogen.

sted, utgiver, år, opplag, sider
Taylor & Francis, 2024
Emneord
CFD, Coaxial jet, Hydrogen jet, Mixing
HSV kategori
Forskningsprogram
Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-108415 (URN)10.1080/19942060.2024.2374977 (DOI)001271048500001 ()2-s2.0-85198554445 (Scopus ID)
Forskningsfinansiär
VinnovaSwedish Research Council FormasSwedish Energy Agency, 2021-04710
Merknad

Validerad;2024;Nivå 2;2024-07-25 (signyg);

Funder: Swedish Mining Innovation;

Fulltext license: CC BY

Tilgjengelig fra: 2024-07-25 Laget: 2024-07-25 Sist oppdatert: 2025-02-05bibliografisk kontrollert
Raj, A., Larsson, I. A., Ljung, A.-L., Forslund, T., Andersson, R., Sundström, J. & Lundström, T. (2024). Evaluating hydrogen gas transport in pipelines: Current state of numerical and experimental methodologies. International journal of hydrogen energy, 67, 136-149
Åpne denne publikasjonen i ny fane eller vindu >>Evaluating hydrogen gas transport in pipelines: Current state of numerical and experimental methodologies
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2024 (engelsk)Inngår i: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 67, s. 136-149Artikkel, forskningsoversikt (Fagfellevurdert) Published
Abstract [en]

This review article provides a comprehensive overview of the fundamentals, modelling approaches, experimental studies, and challenges associated with hydrogen gas flow in pipelines. It elucidates key aspects of hydrogen gas flow, including density, compressibility factor, and other relevant properties crucial for understanding its behavior in pipelines. Equations of state are discussed in detail, highlighting their importance in accurately modeling hydrogen gas flow. In the subsequent sections, one-dimensional and three-dimensional modelling techniques for gas distribution networks and localized flow involving critical components are explored. Emphasis is placed on transient flow, friction losses, and leakage characteristics, shedding light on the complexities of hydrogen pipeline transportation. Experimental studies investigating hydrogen pipeline transportation dynamics are outlined, focusing on the impact of leakage on surrounding environments and safety parameters. The challenges and solutions associated with repurposing natural gas pipelines for hydrogen transport are discussed, along with the influence of pipeline material on hydrogen transportation. Identified research gaps underscore the need for further investigation into areas such as transient flow behavior, leakage mitigation strategies, and the development of advanced modelling techniques. Future perspectives address the growing demand for hydrogen as a clean energy carrier and the evolving landscape of hydrogen-based energy systems.

sted, utgiver, år, opplag, sider
Elsevier, 2024
Emneord
Pipeline transport, Hydrogen, Numerical modelling, Leakage Experiment, Renewable energy
HSV kategori
Forskningsprogram
Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-105267 (URN)10.1016/j.ijhydene.2024.04.140 (DOI)001232412300001 ()2-s2.0-85190604760 (Scopus ID)
Forskningsfinansiär
The Kempe FoundationsThe Kempe FoundationsLuleå University of Technology
Merknad

Validerad;2024;Nivå 2;2024-07-05 (joosat);

Full text license: CC BY 4.0;

Tilgjengelig fra: 2024-04-29 Laget: 2024-04-29 Sist oppdatert: 2024-07-05bibliografisk kontrollert
Kadia, S., Larsson, I. A., Billstein, M., Lia, L. & Pummer, E. (2024). Experimental and numerical investigations of the water surface profile and wave extrema of supercritical flows in a narrow channel bend. Scientific Reports, 14(1), Article ID 12247.
Åpne denne publikasjonen i ny fane eller vindu >>Experimental and numerical investigations of the water surface profile and wave extrema of supercritical flows in a narrow channel bend
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2024 (engelsk)Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 14, nr 1, artikkel-id 12247Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Supercritical flows in channel bends, e.g., in steep streams, chute spillways, and flood and sediment bypass tunnels (SBTs), experience cross-waves, which undulate the free surface. The designs of these hydraulic structures and flood protection retaining structures in streams necessitate computing the locations and water depths of the wave extrema. This study numerically and experimentally investigates the water surface profiles along the sidewalls, the wave extrema flow depths, and their angular locations in a narrow channel bend model of the Solis SBT in Switzerland. The 0.2 m wide and 16.75 m long channel has a bend of 6.59 m radius and 46.5° angle of deviation. The tested flow conditions produced Froude numbers ≈ 2 and aspect ratios ranging from 1.14 to 1.83. Two-phase flow simulations were performed in OpenFOAM using the RNG k–ε turbulence closure model and the volume-of-fluid method. The simulated angular locations of the first wave extrema and the corresponding flow depths deviate marginally, within ± 6.3% and ± 2.1%, respectively, from the experimental observations, which signifies good predictions using the numerical model. Larger deviations, especially for the angular locations of the wave extrema, are observed for the existing analytical and empirical approaches. Therefore, the presented numerical approach is a suitable tool in designing the height of the hydraulic structures with bends and conveying supercritical flows. In the future, the model’s application shall be extended to the design of the height and location of retaining walls, embankments, and levees in steep natural streams with bends.

sted, utgiver, år, opplag, sider
Springer Nature, 2024
Emneord
Curved channel, Experimental study, Numerical simulation, OpenFOAM, Sediment bypass tunnel, Supercritical fow, Wave maxima and minima
HSV kategori
Forskningsprogram
Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-105684 (URN)10.1038/s41598-024-61297-8 (DOI)001234681100084 ()38806520 (PubMedID)2-s2.0-85194857127 (Scopus ID)
Merknad

Validerad;2024;Nivå 2;2024-05-31 (joosat);

Funder: HydroCen (Project No. 90148311); NTNU (Project No. 81772024);

Full text: CC BY license;

Tilgjengelig fra: 2024-05-31 Laget: 2024-05-31 Sist oppdatert: 2025-02-09bibliografisk kontrollert
Nilsson, D., Andersson, A., Larsson, S., Andersson, R., Billstein, M. & Lillberg, E. (2024). Experimental investigation of open channel flow around a hemisphere at different relative depths using 3D-PTV. In: Proceedings of the 21st International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics: . Paper presented at 21st International Symposium on Applications of Laser and Imaging Techniques to Fluid Mechanics, July 8-11, 2024, Lisbon, Portugal.
Åpne denne publikasjonen i ny fane eller vindu >>Experimental investigation of open channel flow around a hemisphere at different relative depths using 3D-PTV
Vise andre…
2024 (engelsk)Inngår i: Proceedings of the 21st International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics, 2024Konferansepaper, Publicerat paper (Fagfellevurdert)
Emneord
Volumetric PTV, Hemisphere, Wake, Velocity field, Relative depth
HSV kategori
Forskningsprogram
Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-108543 (URN)10.55037/lxlaser.21st.16 (DOI)
Konferanse
21st International Symposium on Applications of Laser and Imaging Techniques to Fluid Mechanics, July 8-11, 2024, Lisbon, Portugal
Forskningsfinansiär
Energy Research
Tilgjengelig fra: 2024-08-12 Laget: 2024-08-12 Sist oppdatert: 2025-02-09bibliografisk kontrollert
Kadia, S., Larsson, I. S., Billstein, M., Rüther, N., Lia, L. & Pummer, E. (2024). Investigating supercritical flow characteristics and movement of sediment particles in a narrow channel bend using PTV and video footage. Advances in Water Resources, 193, Article ID 104827.
Åpne denne publikasjonen i ny fane eller vindu >>Investigating supercritical flow characteristics and movement of sediment particles in a narrow channel bend using PTV and video footage
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2024 (engelsk)Inngår i: Advances in Water Resources, ISSN 0309-1708, E-ISSN 1872-9657, Vol. 193, artikkel-id 104827Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

This experimental study investigates the cause of nonuniform invert abrasion observed at sediment bypass tunnel (SBT) bends by examining the variations in velocity distributions, turbulence properties, bed shear stress, and bulk sediment movements under three supercritical bend flow conditions, detailed investigation of such flow is scarce. Using a laboratory-scaled model (1:22) of the downstream bend at Solis SBT, Switzerland, the research utilized particle tracking velocimetry and high-speed cameras with spherical sandstones and glass spheres representing sediments. The results indicate that as the secondary currents develop in the flow direction, the flow properties and sediments redistribute across the channel: the high-momentum fluids are directed toward the outer wall, the bed shear stress increases toward the outer wall, and the sediments are pushed toward the inner wall, which then follow this path downstream, even in straight sections, despite lower bed shear stress. This distribution of sediments, driven by secondary currents, leads to deeper invert abrasions toward the inner wall at SBT bends and downstream sections. Thus, these abrasions are primarily influenced by sediment movement rather than the bed shear stress alone. The study's findings are also valuable for validating future numerical simulations.

sted, utgiver, år, opplag, sider
Elsevier, 2024
Emneord
Bed shear stress, Particle tracking velocimetry, Secondary currents, Sediment bypass tunnel, Sediment movement and invert abrasion, Supercritical bend flow
HSV kategori
Forskningsprogram
Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-110293 (URN)10.1016/j.advwatres.2024.104827 (DOI)001333038800001 ()2-s2.0-85205904494 (Scopus ID)
Merknad

Validerad;2024;Nivå 2;2024-10-09 (sarsun);

Full text license: CC BY 4.0;

Funder: HydroCen (Project No 90148311); NTNU (Project No 81772024);

Tilgjengelig fra: 2024-10-09 Laget: 2024-10-09 Sist oppdatert: 2024-11-20bibliografisk kontrollert
Larsson, S. I. .., Lycksam, H. & Ainegren, M. (2024). Towards flow field measurements around dynamic cross-country skiers. Paper presented at Ninth International Congress onScience and Skiing (ICSS 2023) Saalbach, Austria, March 18-22, 2023. Current Issues in Sport Science (CISS), 9(3), Article ID 006.
Åpne denne publikasjonen i ny fane eller vindu >>Towards flow field measurements around dynamic cross-country skiers
2024 (engelsk)Inngår i: Current Issues in Sport Science (CISS), E-ISSN 2414-6641, Vol. 9, nr 3, artikkel-id 006Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Flow field measurements around cross-country skiers (xc skiers) are lacking in the literature to date. The aim was therefore to investigate the possibility of using particle tracking velocimetry for visualization and measurement of the flow field around xc skiers roller skiing on a treadmill in a wind tunnel. The airflow was seeded with neutrally buoyant helium-filled soap bubbles as tracer particles, following the flow without affecting it. As illumination, two different approaches were tested: first, a laser in the cameras’ line of sight (sagittal plane), then an LED unit directed vertically in a narrow slice, clearly limiting the depth of the measurement volume in the cameras’ line of sight. The flow field was studied at various speeds (3-7 m/s) around a single skier as well as around two skiers in line with the streaming airflow. It was found that the experimental approach has the potential to provide detailed insights, both qualitatively and quantitatively, into the flow field dynamics. The main challenges regarding setup, illumination, seeding, and cameras were identified, and possible improvements to streamline the experimental methodology were discussed. 

sted, utgiver, år, opplag, sider
Bern Open Publishing, 2024
Emneord
Cross-country skiing, flow field visualization, particle tracking velocimetry, wind tunnel, aerodynamics
HSV kategori
Forskningsprogram
Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-105501 (URN)10.36950/2024.3ciss006 (DOI)
Konferanse
Ninth International Congress onScience and Skiing (ICSS 2023) Saalbach, Austria, March 18-22, 2023
Forskningsfinansiär
Swedish Agency for Economic and Regional Growth, 20202610European Regional Development Fund (ERDF), 20202610
Merknad

Validerad;2024;Nivå 1;2024-05-16 (hanlid);

Full text license: CC BY-NC

Tilgjengelig fra: 2024-05-16 Laget: 2024-05-16 Sist oppdatert: 2025-02-05bibliografisk kontrollert
Forslund, T. O. M., Larsson, I. A., Hellström, J. G. & Lundström, T. S. (2023). A dual-lattice hydrodynamic-thermal MRT-LBM model implemented on GPU for DNS calculations of turbulent thermal flows. International journal of numerical methods for heat & fluid flow, 33(5), 1703-1725
Åpne denne publikasjonen i ny fane eller vindu >>A dual-lattice hydrodynamic-thermal MRT-LBM model implemented on GPU for DNS calculations of turbulent thermal flows
2023 (engelsk)Inngår i: International journal of numerical methods for heat & fluid flow, ISSN 0961-5539, E-ISSN 1758-6585, Vol. 33, nr 5, s. 1703-1725Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Purpose

The purpose of this paper is to present a fast and bare bones implementation of a numerical method for quickly simulating turbulent thermal flows on GPUs. The work also validates earlier research showing that the lattice Boltzmann method (LBM) method is suitable for complex thermal flows.

Design/methodology/approach

A dual lattice hydrodynamic (D3Q27) thermal (D3Q7) multiple-relaxation time LBM model capable of thermal DNS calculations is implemented in CUDA.FindingsThe model has the same computational performance compared to earlier publications of similar LBM solvers. The solver is validated against three benchmark cases for turbulent thermal flow with available data and is shown to be in excellent agreement.

Originality/value

The combination of a D3Q27 and D3Q7 stencil for a multiple relaxation time -LBM has, to the authors’ knowledge, not been used for simulations of thermal flows. The code is made available in a public repository under a free license.

sted, utgiver, år, opplag, sider
Emerald Group Publishing Limited, 2023
Emneord
Lattice Boltzmann method, Turbulence, Thermal flows, Direct numerical simulation
HSV kategori
Forskningsprogram
Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-93178 (URN)10.1108/HFF-06-2022-0339 (DOI)000893826100001 ()2-s2.0-85143219027 (Scopus ID)
Forskningsfinansiär
Swedish Research Council, 2017-04390
Merknad

Validerad;2023;Nivå 2;2023-07-13 (sofila);

This article has previously appeared as a manuscript in a thesis

Tilgjengelig fra: 2022-09-22 Laget: 2022-09-22 Sist oppdatert: 2025-02-09bibliografisk kontrollert
Forslund, T. O. .., Larsson, I. A., Hellström, J. G. & Lundström, T. S. (2023). Steady-State Transitions in Ordered Porous Media. Transport in Porous Media, 149(2), 551-577
Åpne denne publikasjonen i ny fane eller vindu >>Steady-State Transitions in Ordered Porous Media
2023 (engelsk)Inngår i: Transport in Porous Media, ISSN 0169-3913, E-ISSN 1573-1634, Vol. 149, nr 2, s. 551-577Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Previously performed experiments on flow through an ordered porous media cell with tomographic particle image velocimetry reveal a complex three-dimensional steady-state flow pattern. This flow pattern emerge in the region where inertial structures have been previously reported for a wide range of packings. The onset of these steady-state inertial flow structures is here scrutinized for three different types of packing using a finite difference method. It is concluded that the onset of the flow structure coincides with a symmetry break in the flow field and discontinuities in the pressure drop, volume averaged body forces and heat transfer. A quantity for identifying the transition is proposed, namely the pressure integral across the solid surfaces. It is also shown that the transition can both increase and decrease the heat transfer dependent on the actual geometry of the porous medium.

sted, utgiver, år, opplag, sider
Springer Nature, 2023
Emneord
FDM, Pore scale, Ordered porous media, Inertial transition
HSV kategori
Forskningsprogram
Strömningslära
Identifikatorer
urn:nbn:se:ltu:diva-93182 (URN)10.1007/s11242-023-01966-w (DOI)001008440200001 ()2-s2.0-85161891565 (Scopus ID)
Forskningsfinansiär
Swedish Research Council, 2017-04390
Merknad

Validerad;2023;Nivå 2;2023-08-15 (hanlid);

This article has previously appeared as a manuscript in a thesis.

Licens fulltext: CC BY License

Tilgjengelig fra: 2022-09-22 Laget: 2022-09-22 Sist oppdatert: 2025-02-09bibliografisk kontrollert
Organisasjoner
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0002-4916-9566