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Near-surface structure and energy characteristics of the Antarctic Circumpolar Current

Advances in Polar Science 2013年第4期24卷 265-272页

作者： GAO Libao YU Weidong WANG Haiyuan LIU Yanliang Center for Ocean and Climate Research First Institute of Oceanography College of Physical and Environmental Oceanography Ocean University of China

Historical surface drifter observations collected from the Southern Ocean are used to study the near-surface structure, variability, and energy characteristics of the Antarctic Circumpolar Current （ACC）. A strong, nearly zonal ACC combined with complex fronts dominates the circulation system in the Southern Ocean. Standard variance ellipses indicate that both the Agulhas Return Current and the East Australian Warm Current are stable supplements of the near-surface ACC, and that the anticyclonic gyre formed by the Brazil warm current and the Malvinas cold current is stable throughout the year. During austral winter, the current velocity increases because of the enhanced westerly wind. Aroused by the meridional motion of the ACC, the meridional velocity shows greater instability characteristics than the zonal velocity does over the core current. Additionally, the ACC exhibits an eastward declining trend in the core current velocity from southern Africa. The characteristics of the ACC are also argued from the perspective of energy. The energy distribution suggests that the mean kinetic energy （MKE）, eddy kinetic energy （EKE）, and are strong over the core currents of the ACC. However, in contrast, EKE/MKE suggests there is much less （more） eddy dissipation in regions with strong （weak） energy distribution. Both meridional and zonal energy variations are studied to illustrate additional details of the ACC energy characteristics. Generally, all the energy forms except EKE/MKE present west-east reducing trends, which coincide with the velocity statistics. Eddy dissipation has a much greater effect on MKE in the northern part of the Southern Ocean.

关键词： mean structure energy characteristic ACC

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Experiment and Numerical Simulation of Free Water Jet by a Central-body Nozzle

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Chinese Journal of Mechanical Engineering 2010年第6期23卷 797-804页

作者： YANG Minguan ZHANG Feng KANG Can GAO Bo School of energy and Power Engineering Jiangsu University Zhenjiang 212013 China

The recent research about cavitation jet mainly focuses on the organ-pipe nozzle and triangular nozzle. The research content mainly includes the optimized design about the structure of nozzles, the observation and flow analysis about the cavitation jet in the water, and the theory of rock attacked by the cavitation jet, while the energy characteristic of the free jet is not studied yet. In China, the research about the central-body nozzle is almost empty. For the purpose of studying the energy characteristic and the structure of free water jet discharged from central-body nozzle, an experiment with phase Doppler particle anemometry（PDPA） technology is carried out to measure the free water jet flow, which is produced by a central-body nozzle under the jet pressure of 15 MPa. While five sections with different axial distances from the nozzle outlet are selected for data process and analysis, the axial and radial velocity and the droplets of the particle size are studied. Meanwhile, numerical calculation of corresponding flow field is conducted by using volume of fluid（VOF） multiphase model, and the jet flow feature is discussed. The experimental and calculating results show that the axial velocity of high speed jet flow dissipates slowly in the air, and the core area and diffused area are discovered. The diameter of droplet in the core area is small, and jet energy is concentrated, while in the diffusion area, water is mingled with ambient air and radial velocity is relatively large. Obvious low-pressure area exists behind the central body and potential cavitation may occur in that area. The proposed research reveals the energy characteristic of free jet discharged from central-body nozzle, provides the theoretical basis for preestimating erosion feature of the central-body nozzle and also the theoretical foundation for revealing the mechanism of erosion.

关键词： central-body nozzle free water jet phase Doppler particle anemometry(PDPA) energy characteristic VOF model

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A Comparative Study on the Excitation of Large Volume Airgun Source with Different Combinations in Hutubi,Xinjiang,China

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Earthquake Research in China 2019年第4期33卷 573-583,I0001页

作者： SU Jinbo WANG Qiong CHEN Hao WEI Yunyun ZHANG Wenxiu WANG Haitao Earthquake Agency of Xinjiang Uygur Autonomous Region Urumqi 830011China The First Monitoring and Application Center CEATianjin 300180China China Earthquake Networks Center Beijing 100045China

In order to study the excitation of large-volume airgun source with different combinations in Hutubi,Xinjiang,China,we conducted a targeted *** method of timefrequency analysis is used to study the signals recorded by a seismometer on the shore of the excited pool,and it is concluded that different gun combinations will lead to different frequency of bubble pulse ***,linear combination method is used to analyze the signal-to-noise ratios of signals excited by different gun combinations which was recorded by seismic stations around the airgun *** order to improve the signal-tonoise ratios,it is more effective to increase the activation energy(the number of excited guns at the same time)than to stack the excited signals with smaller energy repeatedly.

关键词： Airgun source Different gun combinations energy characteristic Frequency characteristic Signal-to-noise ratio

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