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冰川运动速度研究:方法、变化、问题与展望 被引量:8
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作者 管伟瑾 曹泊 潘保田 《冰川冻土》 CSCD 北大核心 2020年第4期1101-1114,共14页
冰川运动将积累区获得的物质输送到消融区,维持着冰川的动态平衡。近年来,随着气候变化,全球大部分冰川面临着剧烈的退缩,而冰川运动变化则较为复杂,引起了学者们的广泛关注。文章系统总结了近年来冰川运动速度的提取方法、冰川运动速... 冰川运动将积累区获得的物质输送到消融区,维持着冰川的动态平衡。近年来,随着气候变化,全球大部分冰川面临着剧烈的退缩,而冰川运动变化则较为复杂,引起了学者们的广泛关注。文章系统总结了近年来冰川运动速度的提取方法、冰川运动速度时空分布与变化及其影响因素的相关研究进展。另外,还探讨了目前冰川运动速度研究中存在的问题和未来的发展趋势。结果表明:基于测杆的方法能够获得精度较高的测量数据,但存在时间和空间上的局限性;基于遥感数据自动化提取的方法应用广泛,但影像之间的配准以及海量数据的计算是当前阶段制约冰川运动速度研究的主要问题;近年来,无人机和地基合成孔径雷达的应用为冰川运动速度研究提供了高精度的数据支撑,但二者在冰川运动研究中的应用还不够广泛。冰川运动速度的分布及其变化在空间上存在明显差异,冰川厚度的变化可能是全球大部分冰川运动速度变化的主要原因,但在单个冰川系统上,冰川运动速度变化较为复杂,其原因还需要进一步探讨。遥感数据的不断丰富,云计算平台的使用,物联网、无人机和地基合成孔径雷达等技术的不断普及,以及星、空、地协同观测的出现将会极大促进未来冰川运动速度研究的发展。此外,冰川动力学过程也将备受关注,成为未来冰川运动研究的热点问题。 展开更多
关键词 冰川运动速度 运动速度提取方法 运动速度变化
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A DYNAMICAL INTERPRETATION OF THE WIND FIELD IN TROPICAL CYCLONES 被引量:3
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作者 郝世峰 崔晓鹏 +2 位作者 潘劲松 周冠博 胡波 《Journal of Tropical Meteorology》 SCIE 2009年第2期210-216,共7页
Based on the primitive equations in polar coordinates and with the supposition that parcel velocity in tropical cyclones is in linear variation and that the distribution of surface pressure agrees with the Fujita form... Based on the primitive equations in polar coordinates and with the supposition that parcel velocity in tropical cyclones is in linear variation and that the distribution of surface pressure agrees with the Fujita formula, a set of equations are derived, which describe the impact of perturbations of central pressure, position of tropical cyclones, direction and velocity of movement of tropical cyclones on the wind field. It is proved that the second order approximation of the kinetic energy of tropical cyclones can be described by the equations under linear approximation. Typhoon Wipha (2007) is selected to verify the above interpretation method, and the results show that the interpretation method of the wind field could give very good results before the landfall of tropical cyclones, while making no apparent improvement after the landfall. The dynamical interpretation method in this paper is applicable to improving the forecasts of the wind field of tropical cyclones close to the coast. 展开更多
关键词 tropical cyclones strong wind dynamical interpretation
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Numerical Investigation of Particle Temperature Change in Supersonic Flows
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作者 Ryohei Sakamaki Masaya Suzuki Makoto Yamamoto 《Journal of Chemistry and Chemical Engineering》 2012年第9期825-831,共7页
Gas-particle two-phase flow is a very important consideration in designing various machines. Although a great deal of theoretical, experimental, and numerical research has been carried out, particle motion in a supers... Gas-particle two-phase flow is a very important consideration in designing various machines. Although a great deal of theoretical, experimental, and numerical research has been carried out, particle motion in a supersonic flow has not been sufficiently clarified. Hence, in order to clarify the interactions between flow and particles, the authors consider the characteristics of particle motion, especially at high temperatures. In the present study, the flow of a gas with a diluted particle load is to be simulated in a conventional converging-diverging supersonic nozzle. The turbulent gas flow in the nozzle is computed with the finite difference and RANS (raynolds averaged navier-stokes simulation) methods. The particle motion is simulated in a Lagrangian manner. In addition, taking into account the light particle loading, a weak coupling method is used. Through this investigation, it is shown that the particle velocity increases monotonically from the nozzle throat to the outlet. And it is shown that particles can be accelerated to higher velocities in helium than in nitrogen, and smaller particles tend to attain higher speed and lower static temperature. 展开更多
关键词 Gas-solid two-phase flow supersonic flow Euler-Lagrange coupling
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Modeling of Bubble Motion in Two Dimensional Space
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作者 Dinesh Khattar Bidhu Bhushan Chakraborty Seema Bansal 《Journal of Energy and Power Engineering》 2012年第12期1945-1951,共7页
The equations of motion of a bubble, expanding adiabatically through an incompressible viscous fluid, are deduced when the centre of the bubble moves in a vertical plane in the presence of gravitational acceleration, ... The equations of motion of a bubble, expanding adiabatically through an incompressible viscous fluid, are deduced when the centre of the bubble moves in a vertical plane in the presence of gravitational acceleration, acting vertically downwards. The non-linear equations of motion obtained are solved numerically for different values of the various parameters of the problem. The path traced by the centre of the bubble and velocity of the centre, the change of radius R with time, and the influence of the buoyancy force, which is experienced by the expanding bubble for different values of the gravitational acceleration on these quantities, are investigated. The radius R(t) of the bubble is found to vary periodically with time when the acceleration due to gravity is small. But when the acceleration due to gravity increases, this periodicity in the value of R(t) with t is lost. The influence of viscosity in determining the periodicity of the bubble motion is also investigated. 展开更多
关键词 BUBBLE incompressible fluid VISCOUS BUOYANCY gravity.
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