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Optimization of the Sefid-Roud Dam desiltation process using a sophist.cated one-dimensional numerical model

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International Journal of Sediment Research 2009年第2期24卷 189-200页

作者： Ali KHOSRONEJAD Dept. University of Guilan. Post.Doctoral Associate St. Anthony Falls LaboratoryUniversity of Minnesota

Although water and soil conservation activities reduce reservoir sedimentation,it is inevitable that reservoirs fed by rivers transporting high amounts of sediment will experience sedimentation. The Ghezel-Ozan and Shah-Roud rivers,which flow to the Sefid-Roud reservoir dam,are both highly sediment-laden and transport significant amounts of sediment in both bed load and suspended load forms to the reservoir. Hence,it seems that the only practical way to remove the sediment from the reservoir is to flush it out using the Chasse method. In the present paper,field measurements of Chasse operation characterist.cs taken in previous years are presented,and a numerical model that simulates this process is introduced. After calibrating the model using field measured data,the calculated results(for reservoir pressure flushing and released sediment volume) of the numerical model were compared with other measured data for the same Chasse operation and the results agree well. Finally,using the numerical simulation results,the best.approaches to ensure highly effective flushing while conserving reservoir water are presented(at least.for the Sefid-Roud dam) . The operation of the bottom outlet gates,the shape of the output hydrograph,and the reservoir water level variation during flushing were optimized. In addition,the numerical model and related parameters,which need to be calibrated,are discussed.

关键词： Pressure flushing Numerical model Reservoir water level Bottom outlet Chasse operation

Numerical st.dy on the effects of progressive gravity waves on turbulence

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Journal of Hydrodynamics 2016年第6期28卷 1011-1017页

作者： Anqing(Elliott) XUAN Bingqing DENG Tao CAO Lian SHEN Department of Mechanical Engineering and Saint anthony falls laboratory University of Minnesota

The wind-wave-ocean syst.m, which contains complex interactive processes, is of great importance for the momentum, heat and mass transport in the atmosphere and ocean and at their interface. In this work, we perform wave-coupled phase-resolved numerical simulations to invest.gate the effect of progressive gravity waves on wind and ocean turbulence. Initially homogeneous turbulence under a finite-amplitude monochromatic surface wave is simulated to reveal how the wave influences the subsurface turbulence. For the interaction between wind-driven waves and shear turbulence in the ocean, new wave-phase-resolved simulation approaches are developed to capture Langmuir cells. Last.y, wind turbulence over one and two progressive waves is simulated to elucidate the dynamics of turbulence coherent st.uctures impacted by surface waves for improved underst.nding of wind-wave growth mechanism.

关键词： wave-ocean interaction Langmuir circulation wave-wind interaction numerical simulation

SOME REMARKS ON HYDROFOIL CAVITATION

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Journal of Hydrodynamics 2012年第3期24卷 305-314页

作者： ARNDT Roger E. A. Saint anthony falls laboratory University of Minnesota MinneapolisMN 55414 USA

This paper reviews numerical and experimental invest.gations of sheet/cloud cavitation carried out at the st. anthony falls laboratory and at two collaborating facilities （Versuchsanst.lt Ftir Wasserbau, Obernach, Germany and Osaka University, Japan） for more than a decade. Although significant advances have been made in the analysis of this flow several issues are st.ll unresolved. The purpose of this paper is to examine the overall features of the problem, review the progress made to date and suggest.avenues for new invest.gation.

关键词： cavitation hydrofoil numerical simulations

Modeling and Simulation of Supercavity with Inertial Force in the Horizontal Curvilinear Motion

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China Ocean Engineering 2014年第1期28卷 31-42页

作者：邹望于开平 R.E.A.Arndt 张广 School of Ast.onautics Harbin Institute of Technology Saint anthony falls laboratory University of Minnesota

To make a curvilinear motion in the horizontal plane is one of the most.contents for realizing the maneuverability of the supercavitating vehicle. It is significant to achieve the controllability and maneuverability of the vehicle in three dimensions both theoretically and practically on research. Models of angle of attack, gravity and inertial force effects on the supercavity in the horizontal curvilinear motion are est.blished, respectively. The supercavity is simulated based on these models in combination with Logvinovich model and the unst.ady gas-leakage rate model at the given ventilation rate, and the effect of the inertial force on it is analyzed numerically. Results show that the maximum deviation of the center line of the cross section of supercavity towards the outward normal direction of its trajectory increases as the cavitation number or curvature radius decrease and always occur in the tail because of the increase of inertial effects along the axis of supercavity from the cavitator when other models and flow parameters are const.nt for the given trajectory curvature. For the variable curvature, the supercavity sheds due to its inst.bility caused by the time-varying angle of attack. The deviation increases along the length of supercavity if the curvature remains the same sign.

关键词： supercavity inertial force curvilinear motion curvature rodius

Snow-powered research on utility-scale wind turbine flows

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Acta Mechanica Sinica 2020年第2期36卷 339-355页

作者： Jiarong Hong Aliza Abraham st.anthony falls laboratory University of MinnesotaMinneapolisMN 55414USA Department of Mechanical Engineering University of MinnesotaMinneapolisMN 55455USA

This paper provides a review of the general experimental methodology of snow-powered flow visualization and super-large-scale particle image velocimetry(SLPIV),the corresponding field deployments and major scientific findings from our work on a 2.5 MW utility-scale wind turbine at the Eolos field *** field measurements were conducted to invest.gate the incoming flow in the induction zone and the near-wake flows from different *** has been shown that these snow-powered measurements can provide sufficient spatiotemporal resolution and fields of view to characterize both qualitatively and quantitatively the incoming flow,all the major coherent st.uctures generated by the turbine(e.g.,blade,nacelle and tower vortices,etc.)as well as the development and interaction of these st.uctures in the near *** work has further revealed several interest.ng behaviors of near-wake flows(e.g.,wake contraction,dynamic wake modulation,meandering and deflection of the nacelle wake,etc.),and their connections with const.ntly-changing inflows and turbine operation,which are uniquely associated with utility-scale *** findings have demonst.ated that the near wake flows,though highly complex,can be predicted with subst.ntial st.tist.cal confidence using supervisory control and data acquisition(SCADA)and st.uctural response information readily available from current utility-scale *** knowledge can be potentially incorporated into wake development models and turbine controllers for wind farm optimization in the future.

关键词： Wind turbine Utility-scale Wake Snow visualization PIV

Simulation-based st.dy of wind-wave interactions under various sea conditions

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Journal of Hydrodynamics 2019年第6期31卷 1148-1152页

作者： Xuanting Hao Tianyi Li Tao Cao Lian Shen Department of Mechanical Engineering and Saint anthony falls laboratory University of MinnesotaMinneapolisMinnesotaUSA

Despite their importance in the ocean environment,the key physical processes in wind-wave interactions are poorly *** a solver developed for undulatory boundaries,we perform numerical simulations of the wind-wave syst.m under various sea conditions,including wind over monochromatic waves,early wind-wave generation,and wind over a broadband wave *** results show that the wave direction and wave age can significantly change the dist.ibution of st.eamwise vorticity in the wind *** wave patterns are observed in the process of wind-wave *** a broadband wave field,the wave growth rate due to wind input is found to depend on the wave st.epness.

关键词： Wind-wave interaction direct numerical simulation large eddy simulation phase-resolved wave simulation

On minimum cavitation number of the ventilated supercavity in water tunnel

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Science China(Physics,Mechanics & Ast.onomy) 2013年第10期56卷 1945-1951页

作者： ZOU Wang YU KaiPing ARNDTREA KAWAKAMIE The School of Ast.onautics Harbin Institute of Technology Saint anthony falls laboratory University of Minnesota

A numerical method consist.d of the cavitation number correction and the model coefficient correction algorithms is presented to simulate the supercavity in water tunnel considering blockage and gravity effects based on the Logvinovich model.A model of the minimum cavitation number is also proposed based on the dimensional analysis theory,and the minimum cavitation number is formulated based on the model and numerical results using the nonlinear least.square method(NLLS).The formula is verified by experiment to some extent.

关键词： supercavity minimum cavitation number Froude number blockage ratio NLLS

Characterist.cs of turbulence transport for momentum and heat in particle-laden turbulent vertical channel flows

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Acta Mechanica Sinica 2017年第5期33卷 833-845页

作者： Caixi Liu Shuai Tang Lian Shen Yuhong Dong Shanghai Inst.tute of Applied Mathematics and Mechanics and Shanghai Key laboratory of Mechanics in Energy and Environment Engineering Shanghai University Department of Mechanical Engineering and st.anthony falls laboratory University of Minnesota

The dynamic and thermal performance of particle-laden turbulent flow is invest.gated via direction numerical simulation combined with the Lagrangian point-particle tracking under the condition of two-way coupling, with a focus on the contributions of particle feedback effect to momentum and heat transfer of turbulence. We take into account the effects of particles on flow drag and Nusselt number and explore the possibility of drag reduction in conjunction with heat transfer enhancement in particle-laden turbulent flows. The effects of particles on momentum and heat transfer are analyzed, and the possibility of drag reduction in conjunction with heat transfer enhancement for the prototypical case of particle-laden turbulent channel flows is addressed. We present results of turbulence modification and heat transfer in turbulent particle-laden channel flow, which shows the heat transfer reduction when large inertial particles with low specific heat capacity are added to the flow. However, we also found an enhancement of the heat transfer and a small reduction of the flow drag when particles with high specific heat capacity are involved. The present results show that particles, which are active agents, interact not only with the velocity field, but also the temperature field and can cause a dissimilarity in momentum and heat transport. This demonst.ates that the possibility to increase heat transfer and suppress friction drag can be achieved with addition of particles with different thermal properties.

关键词： Direction numerical simulation (DNS) Lagrangian tracking approach Flow drag Heat transfer Particle-laden flow

Relationship between wall shear st.esses and st.eamwise vortices in turbulent flows over wavy boundaries

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Applied Mathematics and Mechanics(English Edition) 2019年第3期40卷 381-396页

作者： Lihao WANG Weixi HUANG Chunxiao XU Lian SHEN Zhaoshun ZHANG Applied Mechanics laboratory Department of Engineering MechanicsTsinghua University Department of Mechanical Engineering and Saint anthony falls laboratory University of Minnesota

The relationship between wall shear st.esses and near-wall st.eamwise vortices is invest.gated via a direct numerical simulation(DNS) of turbulent flows over a wavy boundary with traveling-wave motion. The results indicate that the wall shear st.esses are st.ll closely related to the near-wall st.eamwise vortices in the presence of a wave. The wave age and wave phase significantly affect the dist.ibution of a two-point correlation coefficient between the wall shear st.esses and st.eamwise vorticity. For the slow wave case of c/Um = 0.14, the correlation is attenuated above the leeward side while the dist.ibution of correlation function is more elongated and also exhibits a larger vertical extent above the crest. With respect to the fast.wave case of c/U_m=1.4, the dist.ibution of the correlation function is recovered in a manner similar to that in the flat-wall case. In this case, the maximum correlation coefficient exhibits only slight differences at different wave phases while the vertical dist.ibution of the correlation function depends on the wave phase.

关键词： direct numerical simulation(DNS) wall shear st.ess near-wall st.eamwise vortex two-point correlation