Journal of Hydraulic Research最新文献

{"title":"Effect of leading-edge geometry on flow beneath a simulated ice block","authors":"Baafour Nyantekyi-Kwakye, Tanzim Ahmed, Karen Dow","doi":"10.1080/00221686.2023.2240276","DOIUrl":"https://doi.org/10.1080/00221686.2023.2240276","url":null,"abstract":"AbstractThe present article conducted detailed velocity measurements beneath simulated ice blocks with different leading-edge geometries (round, rectangular, upward and downward triangular). The results examined flow separation at the leading-edge, vortex generation, and subsequent vortex propagation. The instantaneous velocity field depicts an unsteady flow dominated by large-scale vortices, with the Kelvin–Helmholtz type instability dominating the shear layer interface. The mode of vortex generation and propagation was influenced by the geometry of the leading edge. These vortices were dominant for the rectangular and upward triangular configurations. Propagation of these vortices creates low-pressure zones beneath the simulated ice block, which can affect the ice block stability. For all ice blocks, the mean flow accelerated, due to flow separation, and this can result in fluctuations in the dynamic pressure field. These events can lead to greater under-turning moments, as well as the interfacial melting of the ice.Keywords: Geometryice blockleading-edgesimulatedstabilityvortices AcknowledgementThe authors are grateful to the Natural Sciences and Engineering Research Council of Canada for their financial support. We also thank Alexander Wall for his assistance in machining the set-up.Disclosure statementNo potential conflict of interest was reported by the author(s).","PeriodicalId":54802,"journal":{"name":"Journal of Hydraulic Research","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135481379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical investigation of cavitating flow in centrifugal pump with improved partially-averaged Navier–Stokes method","authors":"Xiaolin Wang, Yong Wang, Xiao Yuan, Houlin Liu, Linglin Jiang, Wei Xiong","doi":"10.1080/00221686.2023.2236981","DOIUrl":"https://doi.org/10.1080/00221686.2023.2236981","url":null,"abstract":"AbstractThe objectives of this paper are to pursue an accurate numerical method of unsteady cavitating flow at a reasonable calculation cost and investigate the unsteady cavitating flow characteristics of a centrifugal pump. Firstly, the cavitating flow simulations of a centrifugal pump were performed using the partially-averaged Navier–Stokes (PANS) turbulence model and its improved model to evaluate the numerical methods based on experimental data. Compared with the experimental results, the improved PANS turbulence model can better predict the cavitating flows in the pump and has better applicability. Further, the unsteady cavitating flow characteristics of the centrifugal pump, such as the vapour volume fraction, the cavitation-vortex dynamics and the pressure and head fluctuations, were simulated by improved PANS model and discussed. The liquid flow vortex at the end of the cavitation in the impeller is an important reason for the periodic change of the cavitation shape. The periodic change of cavity volume has a certain impact on the pressure pulsation in the impeller and the pump head.Keywords: Cavitating flowcavitation modelcentrifugal pumpturbulence modelvortex Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis work was supported by the National Natural Science Foundation of China [grant number 51979126].","PeriodicalId":54802,"journal":{"name":"Journal of Hydraulic Research","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135738914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transition from undular jump to breaking jump","authors":"Manoj Langhi, Takashi Hosoda","doi":"10.1080/00221686.2023.2239188","DOIUrl":"https://doi.org/10.1080/00221686.2023.2239188","url":null,"abstract":"ABSTRACTIn the present study, a one-dimensional governing equation with a vertical acceleration term is used to analyse the free surface profile of various types of jumps. Initially, the surface profile of various types of jumps are reproduced analytically by using a suitable eddy diffusivity term. The approximations of the surface profile for various jumps are then verified numerically. Based on the comparisons, an empirical relationship between the Froude number and the turbulent diffusivity coefficient is established. The proposed empirical relationship is used in the governing equation to compute the various jumps, where an implicit two dimensional flow is assumed. The obtained results are compared with the experimental data to assure the transition of flow from undular jump to breaking jump. The comparisons of numerical results of wave profiles, pressure distribution, wave length and wave amplitude with the existing experimental data for various Froude numbers indicated the suitability of the proposed empirical relationship. Finally, the transitions of flow from undular jump to breaking hydraulic jump are discussed.Keywords: Froude numberhydraulic jumpopen channel flowsurface profileundular jump","PeriodicalId":54802,"journal":{"name":"Journal of Hydraulic Research","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135814482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On application of empirical mode decomposition for turbulence analysis in open-channel flows","authors":"Andrea Zampiron, Stuart M. Cameron, Vladimir Nikora","doi":"10.1080/00221686.2023.2241838","DOIUrl":"https://doi.org/10.1080/00221686.2023.2241838","url":null,"abstract":"Large-scale coherent structures are key elements of open-channel flow turbulence, quantification of which remains elusive. In this work, we use empirical mode decomposition (EMD) to break down a velocity time series into different modes, denoted as “intrinsic mode functions” (IMFs). Analysis of velocity auto- and co-spectra indicates that large-scale (LSMs) and very large-scale (VLSMs) fluid motions are sufficiently represented by particular groups of IMFs. A correlation between LSMs and VLSMs, identified by the EMD analysis, was found to generate 7% of the Reynolds shear stresses. However, the EMD analysis of surrogate velocity signals with randomized spectral phases demonstrated that the revealed correlation is actually an artefact of the EMD approach and should not be interpreted physically.","PeriodicalId":54802,"journal":{"name":"Journal of Hydraulic Research","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134947881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of CFD to predict the sluice gate jammed","authors":"Chuanming Sheng, Fang Liu, Chao Ma, Jijian Lian, Bin Ma","doi":"10.1080/00221686.2023.2239746","DOIUrl":"https://doi.org/10.1080/00221686.2023.2239746","url":null,"abstract":"AbstractThe problem of sluice gate jamming in moving water occurs frequently in engineering practice. In this study, the reason for gate jamming is investigated by using computational fluid dynamics and verified by model tests with variable friction coefficients. The results show that the gate geometry is reasonable and the downpull force of the sluice gate can be fully utilized. Due to being submerged in water for many years, high friction coefficient is the main reason for the non-closure of a sluice gate. The permissible friction coefficient is related to the submerged weight, available areas of panel and beam, and water level difference. Decreasing the guide vane opening and lowering the water level difference to decrease the average pressure head are feasible ways to promote the gate closure in an emergency. Adding a convex bottom edge and dividing the whole gate into two sections to increase the permissible friction coefficient are effective ways to achieve complete closure in the modification stage.Keywords: CFDfriction coefficientgate closuremodel testsluice gate jammed Disclosure statementNo potential conflict of interest was reported by the author(s).NotationA=guide vane opening ratio (–)A1=available area of the panel (m2)A2=available area of the beam (m2)A2’=available area of the beam with a convex edge (m2)e=gate opening (m)e0=tunnel height (m)E=gate opening ratio (–)Fb=downpull force (kN)Fp=pulling force (kN)Fn=horizontal force (kN)Gg=submerged weight force (kN)h=average pressure head (m)hb=average pressure head on beam (m)hp=average pressure head on panel (m)H=pressure head ratio (–)ΔH=water level difference between the upstream and downstream (m)ΔH0=original water level difference (m)ΔHr=water level ratio (–)l=length of the convex edge (m)Lr=convex edge length ratio (–)P=fluid pressure (Pa)Pback=pressure of back surface (Pa)Pfron=pressure of front surface (Pa)Plower=pressure of lower surface (Pa)Pupper=pressure of upper surface (Pa)Sr=height ratio (–)Ss=height of the water seal (m)Su=height of the upper gate (m)t=time (s)Tb=width of the beam (m)ui, uj=horizontal and vertical velocity components (m s−1)ui’, uj’=horizontal and vertical velocity fluctuation component (m s−1)v=flow velocity (m s−1)vmax=the maximum flow velocity (m s−1)Wb=span of the beam (m)Ws=span of the water seal (m)η=turbulent (eddy) viscosity (Pa s)µ=friction coefficient (–)µp=permissible friction coefficient (–)τij’=turbulent stresses (Pa)υ=dynamic viscosity coefficient (Pa s)Additional informationFundingThis work was supported by the National Key Research and Development Program of China [grant 2018YFC15084], National Natural Science Foundation of China, the Foundation for Innovative Research Groups of the Natural Science Foundation of Heibei Province China, the Foundation for Innovative Research Groups of the Natural Science Foundation of Heibei Province [grant U20A20316 and E2020402074], and Science and Technology Development Projects of Wuqing [grant WQKJ2020","PeriodicalId":54802,"journal":{"name":"Journal of Hydraulic Research","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134948609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrodynamics and turbulence of free-surface flow over a backward-facing step","authors":"Qianyu Luo, Thorsten Stoesser, Razieh Jalalabadi, Zhihua Xie","doi":"10.1080/00221686.2023.2239751","DOIUrl":"https://doi.org/10.1080/00221686.2023.2239751","url":null,"abstract":"ABSTRACTThree large-eddy simulations of open channel flow over a backward-facing step are performed to investigate the effect of submergence on the turbulence, hydrodynamics, and water surface deformation downstream of the step. The deformation of the water surface, the extent of the recirculation zone as well as the strength of the shear layer are a function of relative submergence. All flows downstream of the step exhibit elevated levels of turbulent shear stress and contain significant amounts of turbulent kinetic energy. The instantaneous flow features rollers immediately behind the step and horseshoe-shaped vortices shed from the shear layer, the latter being advected towards the water surface where they cause deformations. It is shown that these vortices can originate from any location along the dividing streamline; however, they contain more energy the closer to the mean attachment location they originate.Keywords: Backward-facing stepfree surfacelarge-eddy simulationrelative submergenceturbulence AcknowledgementsAll simulations were performed on UCL's supercomputer Kathleen.Disclosure statementNo potential conflict of interest was reported by the author(s).NotationAr=channel-width-to-step-height-ratio (–)Cf=skin-friction coefficient (–)Cp=pressure coefficient (–)Er=expansion ratio (–)Fr=Froude number (–)f=frequency (Hz)f=volume force from immersed boundary points (N m−3)g=gravitational acceleration (m s−2)h=step height (m)h1=upstream depth (m)h2=downstream depth (m)K=turbulent kinetic energy (m2 s−2)Lx=computational streamwise length (m)Ly=computational spanwise width (m)Lz=computational wall-normal height (m)p=pressure (Pa)Re=bulk Reynolds number (–)Reh=step height Reynolds number (–)Reτ=friction Reynolds number (–)Ruu=u-velocity auto-correlation (–)Rvv=v-velocity auto-correlation (–)S=submergence (–)St=Strouhal number (–)t=times (s)u=filtered resolved velocity field (m s−1)u¯=time-averaged streamwise velocity (m s−1)−u′w′¯=time-averaged Reynolds shear stress (m s−2)Umax=maximum time-averaged streamwise velocity (m s−1)Um1=upstream spatially-averaged mean velocity (m s−1)Um2=downstream spatially-averaged mean velocity (m s−1)XR=reattachment length (m)Γ=interface between gas and liquid domains (–)ϵ=turbulent kinetic energy dissipation (m2 s−3)ν=kinematic viscosity (m2 s−1)ρ=density of liquid (kg m−3)τSGS=sub-grid scale stress tensor (–)τw=wall shear stress (Pa)ϕ=level set distance function (–)ψ=normalized streamfunction (–)Ωgas=gas domain (–)Ωliquid=liquid domain (–)Additional informationFundingThe work presented in this paper is supported by the EPSRC under project number EP/R022135/1. The third author is a postdoctoral fellow sponsored by EP/R022135/1 whereas the first author has been funded by UCL's Department of Civil, Environmental and Geomatic Engineering.","PeriodicalId":54802,"journal":{"name":"Journal of Hydraulic Research","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134947724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Finite-volume coupled surface-subsurface flow modelling in earth dikes","authors":"Nathan Delpierre, Hadrien Rattez, Sandra Soares-Frazao","doi":"10.1080/00221686.2023.2246936","DOIUrl":"https://doi.org/10.1080/00221686.2023.2246936","url":null,"abstract":"AbstractEarthen embankments are subjected to increasing threats because of climate change inducing sequences of severe drought periods followed by floods, possibly leading to overtopping of the structures. Consequently, the water saturation of the dike can vary significantly both in space and time, and the resulting groundwater flow can affect the free-surface flow in case of overtopping. Conversely, the free-surface flow can modify the pore water content, which controls erosion and slope instabilities. In this paper, a combined approach to such situations is presented, in which the degree of saturation and the flow through the embankment are simulated by solving the two-dimensional Richards equation on an unstructured mesh with an implicit finite volume scheme that is coupled to the system of shallow-water equations solved in one dimension using an explicit finite-volume scheme. The coupled model is validated on several situations of flows through and over earthen embankments with different constitutive materials.Keywords: Embankmentfinite volumenumerical simulationovertopping flowsRichards equationshallow-water equations Disclosure statementNo potential conflict of interest was reported by the author(s).","PeriodicalId":54802,"journal":{"name":"Journal of Hydraulic Research","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134948607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical investigation of air demand by the free surface tunnel flows By WANGRU WEI, JUN DENG and WEILIN XU, <i>J. Hydraulic Res.</i> 59(1), 2021, 158--165, https://doi.org/10.1080/00221686.2020.1744747","authors":"Matthias Bürgler, Benjamin Hohermuth, David F. Vetsch, Robert M. Boes","doi":"10.1080/00221686.2023.2257629","DOIUrl":"https://doi.org/10.1080/00221686.2023.2257629","url":null,"abstract":"The authors developed a novel design equation based on numerical model results by taking into account the effects of water velocity and residual tunnel cross-sectional area above the water surface. The discussers acknowledge the presented approach, but also express their concerns regarding the following points: (i) the validation of the numerical model is superficial as it is based on bulk parameters only and ignores known model limitations; (ii) effects of the air vent characteristics are not considered in the numerical model and consequently neither in the presented design approach; (iii) air entrainment is not considered in the authors' approach but may be important for Froude numbers above 6; and (iv) the general applicability of the design equation due to the small range of considered Froude numbers and the negligence of air vent characteristics which have been shown to significantly impact air demand in outlet tunnels. This discussion aims at clarifying some facts not clearly presented by the authors and identifying limitations of the authors' design equation. Overall, we highlight that the approach describes the unrestricted air discharge and should be limited to the parameter range and assumptions considered for its derivation, i.e. for large air vent parameters (A* > 0.1) and flows with Froude numbers below 10.","PeriodicalId":54802,"journal":{"name":"Journal of Hydraulic Research","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134949481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Linear and nonlinear frequency-domain modelling of oscillatory flow over submerged canopies","authors":"Otto E. Neshamar, Niels G. Jacobsen, Dominic A. van der A, Tom O'Donoghue","doi":"10.1080/00221686.2023.2231433","DOIUrl":"https://doi.org/10.1080/00221686.2023.2231433","url":null,"abstract":"An analytical and experimental study of flow velocities within submerged canopies of rigid cylinders under oscillatory flows is presented, providing insights into the momentum transfer mechanisms between the different flow harmonics. The experimental dataset covers an unprecedented wide range of flow amplitudes with in-canopy velocity reductions ranging between 0.2 and 0.8 of the free stream velocity (from inertia- to drag-dominated in-canopy flow). Results from the analytical model with nonlinear drag compare favourably to the experimental data. Having application of theories for free surface waves over canopies in mind, the effects of linearization of the drag are analysed by comparing sinusoidal and nonlinear model predictions. Finally, a unified prediction formula for in-canopy velocities for sinusoidal, velocity-skewed, and velocity-asymmetric free stream velocities is presented. The formula depends on two non-dimensional parameters related to inertia and drag forces, and the unified formula allows for easy assessment of the maximum in-canopy velocity.","PeriodicalId":54802,"journal":{"name":"Journal of Hydraulic Research","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134947722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Main channel width effects on overtopping-induced non-cohesive fluvial dike breaching","authors":"Vincent Schmitz, Ismail Rifai, Lydia Kheloui, Sebastien Erpicum, Pierre Archambeau, Damien Violeau, Michel Pirotton, Kamal El Kadi Abderrezzak, Benjamin Dewals","doi":"10.1080/00221686.2023.2246923","DOIUrl":"https://doi.org/10.1080/00221686.2023.2246923","url":null,"abstract":"AbstractLaboratory experiments were conducted on the breaching of homogeneous non-cohesive sandy fluvial dikes induced by flow overtopping. Tests were conducted using a main channel, an erodible lateral dike and a floodplain. The main channel width and Froude number prior to overtopping were systematically varied. Breach discharge was deduced from water level measurements and mass conservation. High-resolution 3D reconstructions of the evolving breach geometry were obtained using a non-intrusive laser profilometry technique. The main channel width and Froude number show significant influence on the breach expansion and hydrograph. Breach hydrographs are divided into three types, depending on the Froude number and a non-dimensional main channel width. An adapted fluvial dike breaching model based on the concept of “effective breach width” is proposed. Using the laboratory data, the computed breach discharge is found extremely satisfactory, although the breach downstream expansion is not accurately reproduced by the model.Keywords: Breachchannel width; fluvial dikelaboratory experimentnon-cohesivenumerical modelovertopping flow Disclosure statementNo potential conflict of interest was reported by the author(s).Supplemental dataSupplemental data can be accessed from the online version of the paper. All experimental data are available from the following Zenodo depository: https://doi.org/10.5281/zenodo.1477843.Additional informationFundingThis work was partially funded by the Association Nationale de Recherche et de la Technologie (ANRT) [CIFRE 2015/0015 and CIFRE 2018/1235], the European Regional Development Fund (Programme Opérationnel Interrégional Rhône-Saône 2014–2020) and EDF.","PeriodicalId":54802,"journal":{"name":"Journal of Hydraulic Research","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134947726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}