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Characteristics 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 Institute 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 investigated 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 demonstrates 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

Impact of spray droplets on momentum and heat transport in a turbulent marine atmospheric boundary layer

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Theoretical & Applied Mechanics Letters 2019年第2期9卷 71-78页

作者： Ming Pan Caixi Liu Qingxiang Li Shuai Tang Lian Shen Yuhong Dong Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Department of Mechanical Engineering and St.Anthony Falls Laboratory University of Minnesota Shanghai Key laboratory of Mechanics in Energy and Environment Engineering

Droplet-laden turbulent airflow(i.e. the mixture of dry air and water vapor) in the marine atmospheric boundary layer is described by an open channel flow configuration in direct numerical simulation(DNS). The dispersed phase, the spray droplets are tracked in a Lagrangian framework, and their impact on the carrier airflow is modeled with the two-way coupling between the two phases. A wide-range droplet size is typically found near the air–sea interface according to the sea spray concentration function(SSCF). The interactions of the droplets with turbulent airflow including mass, momentum, and energy exchange are investigated here. We found a balancing mechanism exists in the droplet effects on the turbulent drag coefficient, since spray droplets lead to a decreased vertical turbulent momentum transport, but also lead to an increased droplet contribution to total drag coefficient. For the heat transfer, as droplet mass loading increasing, the total Nusselt number decreases due to the depression of turbulent heat flux and enhanced negative droplet convective flux.

关键词： Direct numerical simulation Air-sea interface Sea spray Turbulent airflow

Numerical study 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 system, 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 investigate 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. Lastly, wind turbulence over one and two progressive waves is simulated to elucidate the dynamics of turbulence coherent structures impacted by surface waves for improved understanding 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 investigations of sheet/cloud cavitation carried out at the st. anthony falls laboratory and at two collaborating facilities （Versuchsanstalt 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 still 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 investigation.

关键词： cavitation hydrofoil numerical simulations

Influence of Coriolis Parameter Variation on Langmuir Turbulence in the Ocean Upper Mixed Layer with Large Eddy Simulation

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Advances in Atmospheric Sciences 2022年第9期39卷 1487-1500页

作者： Dongxiao WANG Guojing LI Lian SHEN Yeqiang SHU state Key laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Department of Mechanical Engineering and st.anthony falls laboratory University of MinnesotaMinneapolisMinnesota 55455USA Southern Marine Science and Engineering Guangdong laboratory(Guangzhou) Guangzhou 510301China

Langmuir turbulence is a complex turbulent process in the ocean upper mixed *** Coriolis parameter has an important effect on Langmuir turbulence through the Coriolis-stokes force and Ekman effect,however,this effect on Langmuir turbulence has not been systematically ***,the impact of the Coriolis parameter on Langmuir turbulence with a change of latitude(LAT)from 20°N to 80°N is studied using a non-hydrostatic large eddy simulation model under an ideal *** results show that the ratio of the upper mixed layer depth to Ekman depth scale(RME)RME=0.266(LAT=50°N)is a key value(latitude)for the modulation effect of the Coriolis parameter on the mean and turbulent statistics of Langmuir *** is found that the rate of change of the sea surface temperature,upper mixed layer depth,entrainment flux,crosswind velocity,downwind vertical momentum flux,and turbulent kinetic energy budget terms associated with Langmuir turbulence are more evident at RME≤0.266(LAT≤50°N)than at RME≥0.266(LAT≥50°N).However,the rate of change of the depth-averaged crosswind vertical momentum flux does not have a clear variation between RME≤0.266 and RME≥*** complex changes of both Langmuir turbulence characteristics and influence of Langmuir turbulence on the upper mixed layer with latitude presented here may provide more information for further improving Langmuir turbulence parameterization.

关键词： Langmuir turbulence Coriolis parameter the upper mixed layer large eddy simulation

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 Astronautics 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 established, respectively. The supercavity is simulated based on these models in combination with Logvinovich model and the unsteady 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 constant for the given trajectory curvature. For the variable curvature, the supercavity sheds due to its instability 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

Simulation-based study 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 system 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 distribution of streamwise 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 steepness.

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 & Astronomy) 2013年第10期56卷 1945-1951页

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

A numerical method consisted 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

Optimization of the Sefid-Roud Dam desiltation process using a sophisticated 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 characteristics 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