Subjects -> ENGINEERING (Total: 2688 journals)
    - CHEMICAL ENGINEERING (229 journals)
    - CIVIL ENGINEERING (237 journals)
    - ELECTRICAL ENGINEERING (176 journals)
    - ENGINEERING (1325 journals)
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    - INDUSTRIAL ENGINEERING (98 journals)
    - MECHANICAL ENGINEERING (115 journals)

HYDRAULIC ENGINEERING (56 journals)

Showing 1 - 57 of 57 Journals sorted alphabetically
Air, Soil & Water Research     Open Access   (Followers: 6)
altlastenforum Baden-Württemberg e.V., Schriftenreihe     Full-text available via subscription   (Followers: 3)
American Journal of Fluid Dynamics     Open Access   (Followers: 48)
American Water Works Association     Hybrid Journal   (Followers: 23)
Annual Review of Fluid Mechanics     Full-text available via subscription   (Followers: 51)
Annual Review of Marine Science     Full-text available via subscription   (Followers: 12)
Archives of Hydro-Engineering and Environmental Mechanics     Open Access   (Followers: 1)
Asian Journal of Water, Environment and Pollution     Hybrid Journal   (Followers: 10)
AWWA Water Science     Hybrid Journal   (Followers: 1)
Bulletin of Marine Science     Full-text available via subscription   (Followers: 8)
Computers & Fluids     Hybrid Journal   (Followers: 30)
Development and Applications of Oceanic Engineering     Open Access   (Followers: 2)
Discover Water     Open Access  
Drinking Water Engineering and Science (DWES)     Open Access   (Followers: 7)
Ecohydrology & Hydrobiology     Full-text available via subscription   (Followers: 4)
Experimental Thermal and Fluid Science     Hybrid Journal   (Followers: 32)
Hydroécologie Appliquée     Full-text available via subscription  
Hydrology: Current Research     Open Access   (Followers: 9)
Hydrometallurgy     Hybrid Journal   (Followers: 11)
Ingeniería del agua     Open Access  
Ingeniería Hidráulica y Ambiental     Open Access  
International Journal of Fluid Power     Hybrid Journal   (Followers: 4)
International Journal of Hydraulic Engineering     Open Access   (Followers: 8)
International Journal of Hydrology Science and Technology     Hybrid Journal   (Followers: 6)
International Journal of Hydromechatronics     Hybrid Journal  
International Journal of Soil, Sediment and Water     Open Access   (Followers: 4)
ISH Journal of Hydraulic Engineering     Hybrid Journal  
Journal of Applied Water Engineering and Research     Hybrid Journal  
Journal of Coastal and Hydraulic Structures (JCHS)     Open Access   (Followers: 2)
Journal of Coastal and Riverine Flood Risk (JCRFR)     Open Access   (Followers: 1)
Journal of Ecohydraulics     Hybrid Journal   (Followers: 1)
Journal of Hydraulic Engineering     Full-text available via subscription   (Followers: 27)
Journal of Hydraulic Research     Partially Free   (Followers: 5)
Journal of Hydrodynamics     Hybrid Journal   (Followers: 2)
Journal of Hydrologic Engineering     Full-text available via subscription   (Followers: 40)
Journal of Hydrology and Hydromechanics     Open Access   (Followers: 4)
Journal of Marine Science and Application     Hybrid Journal   (Followers: 2)
Journal of Ocean University of China (English Edition)     Hybrid Journal   (Followers: 1)
Journal of the Marine Biological Association of the UK     Hybrid Journal   (Followers: 23)
Journal of Water Process Engineering     Full-text available via subscription   (Followers: 3)
Journal of Water Resources Planning and Management     Full-text available via subscription   (Followers: 65)
Journal of Waterway Port Coastal and Ocean Engineering     Full-text available via subscription   (Followers: 7)
LARHYSS Journal     Open Access  
LHB Hydroscience Journal     Open Access  
Limnology and Oceanography: Fluids and Environments     Full-text available via subscription   (Followers: 5)
Marine Genomics     Hybrid Journal   (Followers: 1)
Marine Science     Open Access   (Followers: 4)
Marine Structures     Hybrid Journal   (Followers: 4)
Maritime Studies     Open Access   (Followers: 12)
Navigation     Full-text available via subscription   (Followers: 268)
Proceedings of the Institution of Civil Engineers - Water Management     Hybrid Journal   (Followers: 7)
Regional Studies in Marine Science     Hybrid Journal   (Followers: 1)
Revista de Ingeniería Hidráulica y Ambiental     Open Access  
Revista Ingeniería Agrícola     Open Access  
Ribagua : Revista Iberoamericana del Agua     Open Access  
Water SA     Open Access   (Followers: 2)
Water Science and Engineering     Open Access   (Followers: 13)
Similar Journals
Journal Cover
Journal of Hydrodynamics
Journal Prestige (SJR): 0.768
Citation Impact (citeScore): 2
Number of Followers: 2  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1001-6058 - ISSN (Online) 1878-0342
Published by Elsevier Homepage  [2906 journals]
  • Ship maneuvering prediction based on virtual captive model test and system
           dynamics approaches

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      Abstract: Abstract The maneuvering simulation is carried out through the continuous captive model test and the system dynamics approach. The mathematical maneuvering group (MMG) model is implemented in the virtual captive model tests by using the computational fluid dynamics (CFD) techniques. The oblique towing test (OTT), the circular motion test (CMT), the rudder force test and the open water test are performed to obtain the hydrodynamic derivatives of the hull, the rudder and the propeller, and the results are validated by experimental data. By designing the tests, the number of cases is reduced to a low level, to allow us to evaluate the maneuverability with a low cost and in a short time. Using these obtained coefficients, the system-based maneuvering simulations are conducted to calculate the position and the attitude of the ship, with results in agreement with the free running test results. This procedure can also be used for other hull forms, with reduced workload and with convenience for maneuvering simulation tasks.
      PubDate: 2022-04-27
       
  • Experimental investigation of the effect of the wall proximity on the mode
           transition of a vortex-induced vibrating flexible pipe and the evolution
           of wall-impact

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      Abstract: Abstract The present work experimentally investigates the vortex-induced vibration (VIV) and the pipe-wall impact of a flexible pipe in an oblique flow. The flexible pipe with an aspect ratio of 86.67 and an oblique angle of 30° is immersed in the water flow with the initial gap ratio in the range of 0.2–0.8 and 49.5. The space-time varying oscillation responses in both the in-line and cross-flow directions are recorded using the non-intrusive optical measurement with high-speed cameras in the normal reduced velocity range of 3.40–14.43. The oblique flow induces the spatial variations of the inclination angle to the flexible pipe as a result of the bending deformation during the oscillation. Consequently, the flexible pipe experiences an asymmetrical response along the span and an out-of-sync mode transition in the in-line and cross-flow directions. As the gap ratio decreases, the VIV response is suppressed, and the vibration regions of lower modes are prolonged with the result of the delay of higher excited modes. Additionally, the wall proximity results in an upward deflection of the equilibrium position, and this offset is enlarged with the decrease of the gap ratio. The occurrence of the pipe-wall impact depends on the amplitude of the spatial-temporal varying oscillation and the dominant response mode. Five pipe-wall impact patterns are proposed in terms of the number and the length of the contact pipe segments. The evolution of the pipe-wall impact pattern with the increase of the normal reduced velocity is closely related to the variations of the dominant response mode and the amplitude and the alteration of its spatial distribution.
      PubDate: 2022-04-27
       
  • Experimental and numerical investigations on wave motions over platform
           reef-flat

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      Abstract: Abstract Previous studies have shown that high-frequency (HF) waves, low-frequency (LF) waves and wave set-up coexist on shallow coral reef-flat and jointly contribute to potential floods and subsequent damages of infrastructures and islands on it. To better understand the reef-flat wave dynamics with incident waves and still water level, a wave-flume experiment was performed based on an idealized platform reef composed of a steep reef-face (1:4), a relatively mild reef-rim (1:14) and a horizontal reef-flat. Also, the non-hydrostatic phase-resolving model SWASH was validated against the experiment and then applied to further numerically investigate the effects of reef-rim topographic features on the reef-flat wave motions. The results show that incident waves of a larger wave height and a longer wave period can generate larger LF waves and wave set-up, thereby inducing greater HF waves on the reef-flat. Higher still water level can lead to larger HF waves but result in smaller wave set-up. In contrast to HF waves and wave set-up, LF waves are minimally affected by the still water level. A rim of milder slope and larger edge depth will induce smaller HF and LF waves and set-up on the reef-flat, and thus provide better protection for the reef-flat region. Furthermore, on the reef-flat, the ratio of HF significant wave height to water depth \({H_{s\_h}}/\left( {{h_r} + \overline \eta } \right)\) is approximately constant; the dimensionless LF significant wave height Hs_l/Hs0 and the dimensionless wave set-up \(\overline \eta /\left[ {{T_p}{{\left( {g{H_{s0}}} \right)}^{1/2}}} \right]\) can be related to the inverse wave steepness parameter gT p 2 /Hs0 and the relative reef-flat submergence \(\left( {{h_r} + \overline \eta } \right)/{H_{s0}}\) respectively.
      PubDate: 2022-04-27
       
  • Experimental Investigation of fluid-structure interaction of composite
           hydrofoils in cavitating flow

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      Abstract: Abstract This paper experimentally studies the cavitating fluid-structure interaction of composite hydrofoils with different ply angles. The synchronous measurement system with high-speed camera and for laser Doppler vibrometer (LDV), the feedback pressure regulation system, and the flow rate control system are established. The experimental results of the cavitation evolution show that, compared with the rigid hydrofoil, the composite hydrofoils with +45° ply angle and 0° ply angle accelerate the cavitation inception, and the composite hydrofoil with −45° ply angle delays the cavitation inception. At the same cavitation number, the cloud cavitation of the +45° laminated hydrofoil is the most severe, followed by that of the 0° laminated hydrofoil, and that of the −45° laminated hydrofoil is relatively weak and close to that of the rigid hydrofoil. The analyses of the structural vibration of the composite hydrofoils in different cavitation stages show that the three composite hydrofoils have no significant vibration at the incipient cavitation and the supercavitation, but relatively significant vibration is observed in the sheet and cloud cavitation. The vibration amplitude of the composite hydrofoil with +45° ply angle is the largest, followed by those of the −45°, 0° laminated hydrofoils. In the sheet cavitation, the dominant frequencies of the structural vibration velocity of the +45° laminated hydrofoil and the −45° laminated hydrofoil are the first and second modal frequencies, but no explicit dominant frequency is observed for the 0° laminated hydrofoil. In the cloud cavitation, the dominant frequencies of the three composite hydrofoils mainly include the first modal frequency, the second modal frequency, and the cavity shedding frequency.
      PubDate: 2022-04-27
       
  • Prediction of performance of a non-icebreaking ship in marginal ice zone

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      Abstract: Abstract The Arctic is rapidly transforming into a navigable ocean because of global warming. The retreat of ice extent and widened marginal ice zone (MIZ) in the Arctic made it possible for non-icebreaking commercial vessels to sail into Arctic waters where ice floes of various concentrations and thicknesses exist. The main objective of this work is to estimate the performance of a non-icebreaking cargo ship that sails in the Arctic marginal ice zone. Different numerical approaches are utilized to calculate ice-induced resistance and compared with those proposed in empirical formulas. The comparison shows that the resistances predicted by the two numerical tools differ obviously and are in general smaller in comparison with the ones calculated from the empirical formulas under lower ice concentrations. The total resistances are further calculated to predict the required propulsion powers for the case study vessel to enable navigation under severe ice conditions. This work highlights the significance of developing new and more sophisticated tools for estimation of ship’s ice performance in MIZ, which is the prerequisite to enable non-icebreaking cargo fleet to utilize the Arctic shipping lane.
      PubDate: 2022-04-27
       
  • Research progress on the hydrodynamic performance of water-air-bubble
           mixed flows around a ship

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      Abstract: Abstract The interaction between ship and surrounding fluids generates the water-air-bubble mixed flow laden with numerous droplets and bubbles. The water-air-bubble mixed flow is a complex multi-phase flow phenomenon, which involves intense air-water mixture, complex evolution of interface shape, interactions between multi-scale flow structures and strong turbulent fluctuations. Based on the field observations at sea, a large range of white water-air-bubble flow exists widely around a large-scale sailing ship, and directly affects the hydrodynamic performance of ship from various aspects. This paper reviews the research progress of water-air-bubble mixed flow around a ship. Current knowledge about the formation and evolution mechanism are introduced firstly. Then, the effects of the water-air-bubble mixed flow on ship performance are further reviewed, the main concerns are ship resistance, propulsion performance, slamming and maneuverability. Finally, the future research prospects are summarized.
      PubDate: 2022-04-27
       
  • Vortex structures of dynamic pure yaw test using DDES approach and vortex
           identification method

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      Abstract: Abstract Considered as the building blocks, vortex structures with variety of sizes and intensity are widely recognized in the viscous flow field around ship. In this paper, the computational fluid dynamics (CFD) solver, naoe-FOAM-SJTU, coupled with delayed detached-eddy simulation (DDES) is adopted to analyze the vortex structures around the benchmark model Yupeng Ship in dynamic pure yaw tests, which are captured by third generation of vortex identification method. The good agreement of the predicted force/moment by DDES method with the experimental data indicates that the present numerical schemes are reliable and robust. Three vortex identification methods, Q-criteria, ΩR and Liutex, are used to capture the vortex structures around the hull. The large separated flow is able to be investigated by these three methods, in which more vortex structures are captured by ΩR approach and Liutex method with scalar, vector and tensor form seems to be more suitable for analyzing the flow mechanism around the hull in dynamic pure yaw test. In general, each vortex structure corresponds to a dominant positive/negative axial Liutex and a bound vortex pair. The streamlines are spiral in the large separated flow, indicating that the flow in corresponding region is rotational. But the rotation of the flow is not directly related to the intensity of Liutex.
      PubDate: 2022-04-19
       
  • Determination of groundwater flow regimes based on the spatial non-local
           distribution of hydraulic gradient: Model and validation

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      Abstract: Abstract The groundwater flow in natural aquifers can change from the Darcy flow to the non-Darcian flow due to a variety of causes, such as the increase of the Reynolds number in the highly permeable media or the decrease of the hydraulic gradient below a threshold in the low-permeability media, while the representative flow regime cannot be reliably determined using the traditional criteria. To address this challenge, this paper proposes a new term called the equivalent hydraulic gradient (EHG) by generalizing the differential form of the Darcy’s law using a spatial integral of the upstream hydraulic head. The nonlocal spatial variation of the hydraulic head difference between upstream and downstream zones is assumed to be the potential cause of the transition of the groundwater flow regimes. This assumption is analogous to the common assumption used for quantifying the anomalous pollutant transport in the geological media. Applications of this idea show that the EHG concept could distinguish three main flow regimes, namely the Super-Darcy flow, the Darcy flow, and the Sub-Darcy flow, although the Super-Darcy flow regime is rarely observed in the laboratory column flow experiments. Results of this study therefore shed lights on the interpretation of the fundamental dynamics of the groundwater moving in various heterogeneous aquifers, and may lead to the rebuilding of the hydrodynamics of the surface water, the groundwater, and the soil.
      PubDate: 2022-04-19
       
  • Experiment on surface wake of internal waves generated by underwater
           vehicle in stratified fluids

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      Abstract: Abstract The surface flow field of internal waves generated by the underwater vehicle is very weak. In order to study the characteristics of the surface wake of internal waves, a surface particle image velocimetry (PIV) technique which can be used to measure the flow field in the order of mm/s is developed. Breakthrough is made with respect to the key technique measuring the micro-velocity flow field of internal waves on the water surface in stratified fluids. The wake generated by SUBOFF model is measured in stratified fluid tank, and the surface flow field of internal waves is successfully measured for the first time. The experimental results are compared with predicted results by the classical Tuck’s internal wave theory. The results show the characteristics of the surface wake signature of internal waves and the variation of the angle between internal wave beams and the surface flow velocity of internal wave with the towing speed of the model are in good agreement. It provides support for further research on wake signature remote sensing of internal waves in laboratory.
      PubDate: 2022-04-19
       
  • An experimental study on the velocity fluctuations generated by the flow
           past fixed spheres

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      Abstract: Abstract We perform a series of experiments to study the velocity fluctuations generated by the flow past fixed spheres. Planar particle image velocimetry (PIV) is carried out to characterize the properties of the liquid fluctuation. The fluctuation induced by the spheres can be decomposed into the temporal fluctuation and the spatial fluctuation, which represent the contribution of flow instability and spatial inhomogeneity, respectively. In particularly, we focus on the contributions of temporal fluctuations and spatial fluctuations between low and high Reynolds number. At low Reynolds number (20 < Re ≤ 200), the total fluctuation mostly comes from the spatial fluctuation and increases as the area of velocity deficit in the wake of the sphere increases. The temporal fluctuation cannot be neglected at larger Reynolds number (200 < Re ≤ 700), and the total velocity fluctuation is induced by both flow instability and spatial inhomogeneity. Furthermore, the energy distribution in the flow direction and the span direction also changes drastically as the Reynolds number increases. The wavenumber spectra of fluctuations show a −3 slope at large scale, −5/3 slope at small scale. The starting scale of the −3 slope decreases with the increase of the Reynolds number. Specifically, it is consistent with the integral length scale Λ for Re > 200, but not for Re < 200. The ending scale is around λ = 0.5d and decreases slightly as Re increases.
      PubDate: 2022-04-19
       
  • A general two-phase mixture model for sediment-laden flow in open channel

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      Abstract: Abstract This work extends the sediment-laden mixture model with consideration of the turbulence damping and particle wake effects under the framework of improved efficiency and accuracy. The mixture model consists of the continuity and momentum equations for the sediment-laden mixture, and the continuity equation for the sediment. A theoretical formula is derived for the relative velocity between the water and sediment phases, with consideration of the effects of the pressure gradient, the shear stress and the lift force. A modified expression of the particle wake effect, inducing the local turbulence enhancement around the sediment particle, is employed to improve the turbulent diffusion of the coarse sediment. The km-εm model is proposed to close the mixture turbulence, with the turbulence damping effect due to the high sediment concentration expressed by the density-stratification term without an empirical parameter. The km-εm turbulence model requires smaller computational work and offers better results than an empirical density-stratification turbulence model in high sediment concentration cases. Consequently, with the proposed mixture model, the sediment transport in the open channel under a wide range of sediment sizes and concentrations can be revealed with the results in good agreement with experimental data for the velocity, the sediment concentration and the turbulent kinetic energy.
      PubDate: 2022-04-19
       
  • Experimental and numerical investigations of the collapse of a
           laser-induced cavitation bubble near a solid wall

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      Abstract: Abstract With the collapse of cavitation bubbles near the wall, micro-jets and shock waves will be formed, to generate a high-pressure load and to cause the cavitation damage on the surface of the hydraulic machinery. Due to the rapid development of the cavitation bubble collapse process (in the time scale of hundred nanoseconds), the time resolution of the conventional high-speed cameras should reach more than one million frames per second, which will limit the spatial resolution, and obscure the details of the cavitation bubble shape near the cavitation bubble collapse moment. In this paper, with the help of the laser cavitation bubble photogrammetry system with nanosecond-micron space-time resolution, the experiment is carried out for the cavitation bubble collapse morphology evolution near the wall. The morphological characteristics of the cavitation bubble collapse at specific times are analyzed. With the help of the OpenFOAM code, the collapse process of the cavitation bubble near the solid wall is calculated. It is shown that the cavitation bubble near the wall collapses in an axial symmetric heart shape and the micro-jet directed to the wall will pull the cavitation bubble towards the wall. The counter-jet generated in the rebound stage will drive the cavitation bubble to move away from the wall. The numerical simulation of the cavitation bubble shape in the collapse period is well consistent with the experimental results, but the ability to capture the shock wavefront needs to be improved. Under the conditions studied in this paper, the cavitation bubble collapse micro-jet velocity can reach up to a hundred meters per second both in the experiment and the numerical simulation.
      PubDate: 2022-04-16
       
  • Risk assessment of erosive aggressiveness due to the condensation shock by
           numerical simulation

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      Abstract: Abstract Cavitation is, for the engineering areas such as fluid machinery and ship propulsion, a known source of erosion. The erosion damage due to cavitation bubble collapse can lead to extreme failure events, implying the replacement of a ship propeller or a turbine in a hydropower plant, all of which are very costly operations. The dynamics of cavitation hydraulic structure is of great importance for cavitation erosion. As a result, the blade surface endures some extremely high stresses, which lead to the cause of wear. Two major mechanisms, re-entrant jet as well as condensation shock, are known to such transient cavitating flow. In the present work we study the latter since less has been reported for the erosion caused by such an unsteady cavitating flow. We adopted an energy transportation equation based method, combined with a collapse event detection strategy, to carry out numerical erosion risk assessment for erosive aggressiveness due to the condensation shock. Comparing with the paint test, our result shows good agreement in the erosive pattern. We further discussed the hydrodynamics of the related flow structures.
      PubDate: 2022-04-16
       
  • Tuning turbulent convection through rough element arrangement

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      Abstract: Abstract The tuning of turbulent Rayleigh-Bénard (RB) convection in a box is realized numerically by designed rough element arrangement. Considering the nonlinear dynamics of the thermal turbulence system, five models with rough elements of different widths and the same height are proposed to tune the fluid flow heat-transport capacity. Numerical simulations are performed using spectral element method for Rayleigh number in the range 106 ≤ Ra ≤ 109 and a fixed Prandtl number Pr = 0.7. It is found that heat transport is enhanced for large roughness widths as the interaction between the large-scale circulation and secondary flows inside the cavity regions between the rough elements promotes the eruptions of thermal plumes, but is suppressed for small ones as more heat are trapped inside the cavities. In all the rough models studied, different scaling exponents for the heat transport are identified and the influences of roughness arrangement on flow structure are studied.
      PubDate: 2022-04-16
       
  • The dynamics of river confluences and their effects on the ecology of
           aquatic environment: A review

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      Abstract: Abstract Confluences act as critical nodes in a river system. They affect hydrodynamics, sediment transport, bed morphology, and eco-hydraulics of the river system. Convergence of streams produces the complex mechanism of flow momentum and mass mixing which may affect the aquatic environment locally and even lasting for a long distance downstream. The confluence creates a hotspot for the river system’s ecological change, which usually leads to changes in water temperature, suspended-sediment load, bed material, nutrient concentrations, water chemistry, and organic-matter content. Hence, the dynamics of river confluences are very complex and have critical effects on river system’s water environment and ecology. For this reason, a review summarizing turbulent flow, sediment transport, morphological-dynamics, mixing processes, and their effects on the ecology of the aquatic environment at river confluences is in order. A future research agenda and opportunities pertinent to river confluence are vitally emphasized as a multidisciplinary research topic.
      PubDate: 2022-02-17
       
  • FSI simulation of dynamics of fish passing through a tubular turbine based
           on the immersed boundary-lattice Boltzmann coupling scheme

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      Abstract: Abstract The anadromous fish can pass through turbines of run-of-the-river hydropower stations to reach the downstream watershed, but their mortality is significant because of the complex turbine structure, the fast-rotating runner, and the special flow patterns. Numerical simulations of the dynamics of fish passing are a challenging task, because the fish motion in the turbines involves a strong fluid-structure interaction (FSI). In this paper, the 3-D immersed boundary-lattice Boltzmann (IB-LB) coupling scheme is proposed to treat the FSI between the water and the fish. The process of one fish and three fish passing through a tubular turbine is simulated on a graphics processing unit (GPU) platform. The fish motion postures (translation and rotation), the fish body pressure distributions and histories are analyzed, and the results are consistent with the previous studies. This paper presents the IB-LB models, the simulation procedures, the specific treatments, and related results, to demonstrate the effectiveness of the IB-LB coupling scheme in simulating FSI problems and its application prospects in developing fish-friendly turbines.
      PubDate: 2022-02-01
       
  • Energy dissipation on stepped spillways and hydraulic
           challenges—Prototype and laboratory experiences

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      Abstract: Abstract Stepped cascades, chutes and spillways have been in use for more than three millennia. With the introduction of new construction materials and techniques, the staircase chute design has regained some interest within the last forty years. The stepped invert increases significantly the energy dissipation occurring above the steep chute and reduces the size of the required downstream stilling structure. The application of stepped chutes further encompasses in-stream re-aeration and water treatment plant cascades, to enhance the air-water transfer of atmospheric gases and of volatile organic components. However, the engineering design of stepped spillways is not simple because of the hydrodynamic challenges, with several markedly different flow regimes, some complicated two-phase air-water fluid dynamics and massive rate of energy dissipation above the stepped chute. Simply, the technical challenges in the hydraulic design of stepped spillways are massive. This review paper examines the hydraulic characteristics of stepped chute flows and develops a reflection on nearly three decades of active hydraulic research, including recent field measurements during major flood events. The author aims to share his passion for the complicated hydraulic engineering, as well as some advice for engineering professionals and researchers.
      PubDate: 2022-02-01
       
  • Experimental study of non-uniform bubbles in a plume

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      Abstract: Abstract The bubble plume is an important flow phenomenon, ubiquitous in many fields. The non-uniform bubbles in a plume are often simply considered as uniform and moving with a same slip velocity in an integral model. This study aims to have a better understanding of the behavior of the non-uniform bubbles in a plume. A set of experiments are conducted in a transparent water tank, in which the air plumes are generated through different injectors to vary the spectrum of the bubble size. The shadow images of the bubbles are simultaneously recorded with the illumination of a plane backlight. The algorithm used in the image analysis for tracing the bubbles is a newly developed multi-frame method based on the predictor-corrector method, with a good accuracy in estimating the size and the velocity of the overlapped bubbles based on the bubble shadow images. The bubbles are divided into several groups by their equivalent diameters with an interval of 0.5 mm. The spectrums of the bubble size and the void fraction are measured. It is found that the bubbles of different sizes show different dynamics features, resulting in a difference in the radial distribution. It is shown that the large bubbles gather in the center of the plume, while the medium bubbles spread the widest and even wider than the small bubbles. The difference can be explained by the effects of the transverse lift force and the amplitude of the bubble oscillation.
      PubDate: 2022-02-01
       
  • Numerical study of free end effect of cylinder with low aspect ratios on
           vortex induced motion

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      Abstract: Abstract In this paper, numerical simulation is conducted via our in-house solver, vim-FOAM-SJTU, developed on open-source software, OpenFOAM. Flow around static rigid cylinders and elastically mounted rigid cylinder constrained to free stream with free end are numerically investigated. Some significant conclusions are made by analyzing the different results between cases with and without free end. The turbulence model is implemented with a shear stress transport-based (SST-based) improved delayed detached eddy simulation (IDDES) approach in the vim-FOAM-SJTU. Firstly, The paper starts with the application of the vim-FOAM-SJTU solver to flow past fixed cylinder with free end at Reynolds number 43 000. The numerical results are compared with experimental data. Comparison are satisfactory which implies the validity and accuracy of the current computational fluid dynamics (CFD) solver. The flow visualization in the vicinity of free-end is discussed. Subsequently, the solver is utilized to simulate the free end effect associated with the VIM of a cylinder submerged in current. The motion responses under different inflow velocities are studied. The relationship between transverse motion frequency, in-line motion frequency is discussed. Lastly, the effect of the free end on the vortex of the wake field is analyzed by comparing the 3-D vorticity diagrams of the free end cylinder. The responses of circular cylinder with or without free end are compared.
      PubDate: 2022-02-01
       
  • Numerical simulations of sloshing waves in vertically excited square tank
           by improved MPS method

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      Abstract: Abstract Faraday wave is a phenomenon of sloshing due to a heave motion of a partially filled tank, which is also called parametric instability or parametric resonance. In the present paper, the phenomenon of faraday wave in a pure heave excited square tank is numerically simulated through the moving particle semi-implicit (MPS) method. The surface tension effect and a new Dirichlet boundary condition for the pressure Poisson equation are considered to avert unphysical fragmentation and clustering of particles in splash simulation. In the numerical simulation, the evolution of wave motion, and the non-linearity together with breaking phenomenon of faraday wave can be observed. The agreement is good in general, both amplitude and phase. Besides, the parameter studies including the excitation frequency and the forcing amplitude are carried out to analyses the mechanism of resonances response.
      PubDate: 2022-02-01
       
 
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