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讲座信息

3月23日工学院联合学术报告


澳门在线威尼斯官方联合学术报告( 力学与空天技术系、能源与资源工程系)
报告一:Vibrodynamics of ‘solid+fluid’
By Professor V.A.Vladimirov,University of York, UK
报告二:Modeling of reactive fluid flow and geochemical transport in geological media
By Tianfu Xu, Earth Sciences Division, Lawrence Berkeley National Laboratory
 
报告一摘要:
Vibrational mechanics (vibromechanics) is an active interdisciplinary research area that is closely linked to engineering and many other applied subjects. It studies the motions of various mechanical systems in the presence of high frequency oscillations of their parameters. This lecture is devoted to the vibromechanics of dynamical systems composed of solids and a fluid (`solid+fluid) with the use of the averaging method. First we present the averaging procedure in two forms. For the achieving of maximal transparency we consider the most celebrated example of a pendulum with a vibrating pivot (the Stephenson – Kapitza pendulum). The first form of the averaging procedure operates with the exact governing equations. The second form directly uses the least action principle, in which the averaging procedure appears naturally and the conservation laws follow automatically. The presented results provide the full model for both ‘fast’ and ‘slow’ motions. The main advantage of the ‘least action’ form of the procedure is the substantial reduction in the analytical calculations, which are typically cumbersome for the asymptotic methods. In the second part of the lecture we apply the least action form of the averaging procedure to the dynamics of a solid in an inviscid incompressible fluid that fills a vibrating vessel of an arbitrary shape. The solid can be either homogeneous or inhomogeneous in density. The results include equations for ‘slow’ motions, ‘slow Lagrangian’, the ‘slow energy and a ‘vibrogenic force’, exerted by a fluid into a solid. The case of N homogeneous solids is also outlined. We describe our calculations, present results in an accessible form, and discuss related examples, properties, and conjectures. The examples of either homogeneous or inhomogeneous spherical solid are considered in details. The connection to the viscous ‘steady streaming theory’ is clarified.
 
报告二摘要:
A comprehensive coupled program TOUGHREACT for multiphase fluid and heat flow, solute transport, and geochemical processes has been developed at Lawrence Berkeley National laboratory (LBNL), which is widely used for geological and environmental problems. A brief overview of this modeling capability will be given. Several application examples will be used to illustrate the applicability. First example is related to CO2 geological sequestration. CO2 is co-injected with either H2S or SO2 into a Gulf Coast sandstone. Changes in water chemistry, mineral dissolution and precipitation, and amounts of CO2 hydrodynamic, solubility, and mineral trapping are studied using the program. Other examples, dealing with nuclear waste geological disposal, mineral scaling and changes in porosity and permeability in a geothermal field, and environmental and groundwater quality problems, will be also presented.
 
主持人:唐少强
时  间:3月23日(周五)下午2:30
地  点:北京大学力学楼四楼434会议室
联系人:刘才山,62756177
力学与空天技术系研究生必须参加

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