3D Lagrangian particle tracking dataset of flow around a surface-mounted cube in an open-channel flume at two relative submergence conditions. Particle tracks were reconstructed using Shake-The-Box and used to obtain Eulerian velocity fields. The dataset provides time- averaged velocity and acceleration fields for two relative submergence conditions: Low (RS = 1.25) and High (RS = 2.00). Velocity and acceleration data are stored in separate files. Each row in the files represents a single grid point in the reconstructed Eulerian field.

Climate change and urbanization have caused increased surface runoff and reduced infiltration, which together exacerbates urban flooding. The hypothesis in this study is that green engineering from renewable marine biomass is a resource-efficient approach that utilize the intrinsic properties of brown seaweed for material development and optimization to achieve functional properties with potential for stormwater management. The study focuses on understanding the structure-property relationship for material development, while making use of the entire seaweed as a resource for a 100 % yield combined with non-toxic processing. The stipes, byproducts of seaweed harvesting, were fibrillated directly without using any chemicals, at an energy consumption of 2 kWh/kg, resulting in a green paste that was subsequently diluted to set concentrations and freeze dried to obtain a porous structure. CaCl2 crosslinking of the structures was optimized to achieve a porous biomaterial with porosities between 80 % and 94 % that kept its structural integrity upon absorption via a post-crosslinking approach. The drying process was optimized to achieve dimension stability wherein a second freeze-drying cycle and solvent method resulted in structures with dimension stability, compared to the uneven shapes that was obtained for materials dried directly at room temperature. The developed porous biomaterial displayed prominent absorption capacity with deionized water and stormwater absorption capacities around 3500 % and 4000 %, respectively. The cyclic water absorption studies also confirmed that the material can withstand during multiple cycles of absorption-drying with excellent structural integrity.

Turbulent flow through a 90◦ bend with a curvature ratio 𝛾 = 0.3 has been investigated experimentally using time-resolved three-dimensional particle tracking velocimetry (PTV) at 𝑅𝑒 = 12800. Fluorinated ethylene propylene tubes were installed upstream and downstream an opaque bend, and index-matching was achieved using a mixture of 94.1% of water and 5.9% of glycerol. The PTV measurements have been performed both before and after the bent section in order to provide further understanding of bent flow in general, and the swirl-switching phenomenon in particular. From the streamline pattern in the upstream tangent it is shown that the effect of the bend is minor for distances exceeding about two pipe diameters upstream from the bend. In the downstream tangent, elongated quasi-streamwise vortices have been identified using the 𝜆2-criterion on time-averaged data, and it is conjectured that the dynamics of these vortices might play an important role in the dynamics of the swirl-switching. This is in line with previously performed direct numerical simulations (DNS) of flow in toroidal pipes. To further characterize swirl-switching, two and three-dimensional proper orthogonal decomposition have been performed. It is shown that the cross-stream in-plane mode shapes do not differ significantly between the two approaches. Similarly as found in DNS, the mode shapes in the bend symmetry plane e

This study focuses on replacing traditional gas-fired furnaces with sustainable low-pressure carburizing (LPC) and gas cooling methods. The project leverages advanced computational tools for predicting quenching outcomes (e.g., cooling rates, material properties, and distortions) to enable sustainable and efficient production. 

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.

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.

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.

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.

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.