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Measurement of mean flow and Turbulence Structure of Open-channel flow through Simulated Flexible Vegetations by Ultrasonic Velocity Profiler

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Measurement of Mean Flow and Turbulence Structure of Open-ch...

The energy conversion rates from eddies and mean fl ow into internal lee waves in the global ocean

第十六届全国水动力学研讨会

作者： C. W. Li (Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hong Kong) Y. P. Chen (Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hong Kong) (College of Harbour, Waterway and Coastal Engineering, Hohai University, Nanjing, 210098)

＜正＞This paper presents the details of the methodology and the use of Ultrasonic Velocity Profiler （UVP） in measuring the mean flow and turbulence structure of open channel flow passing through an array of flexible rubber rods, which simulates the problem of flow through flexible vegetation. Details of the resolution and accuracy achievable by the instrument are studied, and the three dimensional profiles of mean flow and turbulence intensity are obtained and their properties are described.

关键词： Ultrasonic Velocity Profiler(UVP) flexible vegetation mean flow turbulence intensity

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Journal of Oceanology and Limnology 2022年第4期40卷 1304-1313页

作者： Bing HAN Laboratory for Coastal Ocean Variation and Disaster Prediction College of Ocean and MeteorologyGuangdong Ocean UniversityZhanjiang 524088China State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Institut für Meereskunde Universität HamburgHamburg 20146Germany Key Laboratory of Climate Resources and Environment in Continental Shelf Sea and Deep Sea of Department of Education of Guangdong ProvinceGuangdong Ocean UniversityZhanjiang 524088China

Internal lee waves play an important role in transferring energy from eddies to small scale ***,the energy conversion from eddies into lee waves in the global ocean remains poorly *** rates from eddies and from mean fl ow in the global ocean were diff erentiated using single beam sounding data,stratifi cation from climatology,eddy velocity,and mean fl ow from a global ocean *** global integral energy conversion from eddies is estimated to be 0.083 TW and is almost twice as that from the mean fl ow.A new method was developed to study the uncertainties of energy conversion caused by dealing with the topographic *** show that diff erent data processing procedures,and the resolution and accuracy of topographic data have a signifi cant impact on the estimated global energy conversion.

关键词： internal lee waves eddies mean flow energy conversion topography

Lattice Boltzmann simulations of oscillating-grid turbulence

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Journal of Hydrodynamics 2017年第1期29卷 68-74页

作者：张金凤张庆河 JeromeP.-Y.Maa 乔光全 Department of Physical Sciences Virginia Institute of Marine Science School of Marine Science College of William and Mary Fourth Harbor Engineering Investigation and Design Institute Co. Ltd. China Communications Construction Company

The lattice Boltzmann method is used to simulate the oscillating-grid turbulence directly with the aim to reproduce the experimental results obtained in laboratory. The numerical results compare relatively well with the experimental data through dete- rmining the spatial variation of the turbulence characteristics at a distance from the grid. it is shown that the turbulence produced is homogenous quasi-isotropic in case of the negligible mean flow and the absence of secondary circulations near the grid. The direct numerical simulation of the oscillating-grid turbulence based on the lattice Boltzmann method is validated and serves as the founda- tion for the direct simulation of particle-turbulence interactions.

关键词： Oscillating grid quasi-isotropic homogenous turbulence mean flow lattice Boltzmann method

Evaluation of Mid-Depth Currents of NCEP Reanalysis Data in the Tropical Pacific Using ARGO Float Position Information

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Advances in Atmospheric Sciences 2005年第5期22卷 677-684页

作者：谢基平朱江许黎郭品文 Institute of Atmospheric Physics Chinese Academy of Sciences Department of Meteorology Nanjing University of Information Science & Technology Nanjing 210044 Department of Meteorology Nanjing University of Information Science & Technology

The global project of the Array for Real-time Geostrophic Oceanography （ARGO） provides a unique opportunity to observe the absolute velocity in mid-depths of the world oceans. A total of 1597 velocity vectors at 1000 （2000） db in the tropical Pacific derived from the ARGO float position information during the period November 2001 to October 2004 are used to evaluate the intermediate currents of the National Centers for Environmental Prediction reanalysis. To derive reliable velocity information from ARGO float trajectory points, a rigorous quality control scheme is applied, and by virtue of a correction method for reducing the drift error on the surface in obtaining the velocity vectors, their relative errors are less than 25%. Based on the comparisons from the quantitative velocity vectors and from the space-time average currents, some substantial discrepancies are revealed. The first is that the velocities of the reanalysis at mid-depths except near the equator are underestimated relative to the observed velocities by the floats. The average speed difference between NCEP and ARGO values ranges from about -2.3cm s^-1 to -1.8 cm s^-1. The second is that the velocity difference between the ocean model and the observations at 2000 dB seems smaller than that at 1000 dB. The third is that the zonal flow in the reanalysis is too dominant so that some eddies could not be simulated, such as the cyclonic eddy to the east of 160°E between 20°N and 30°N at 2000 dB. In addition, it is noticeable that many floats parking at 1000 dB cannot acquire credible mid-depth velocities due to the time information of their end of ascent （start of descent） on the surface in the trajectory files. Thus, relying on default times of parking, descent and ascent in the metadata files gravely confines their application to measuring mid-depth currents.

关键词： ARGO floats mid-depth ocean currents reanalysis quantitative comparison mean flow

THE MODULATIONAL THEORY OF NONLINEAR GRAVITY-WAVE IN FLUID WITH VARYING DEPTH AND NONUNIFORM CURRENT

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Acta Mechanica Sinica 1991年第1期7卷 12-20页

作者： Chen Yansheng (1) Zhou Chinpu (1) 1. Zhongshan University Guangzhou China

By means of WKB expansions, new fourth order evolution equations are derived for two-dimensional Stokes waves over the bottom with arbitrary depth. The effects of slowly varying depth h= h (ε~2 x) and current U=U(ε~2x, ε~2t, ε~4z) on the evolution of a packet of Stokes waves are considered as well. In addition, numerical simulation is performed for the evolution of single envelope by finite-difference method.

关键词： Stokes wavepacket WKB expansion mean flow evolution equation