排序方式: 共有38条查询结果,搜索用时 31 毫秒
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MAN WenMin & ZHOU TianJun The State Key Latoratory of Numerical Modeling for Atmospheric Sciences Geophysical Fluid Dynamics 《科学通报(英文版)》2011,(Z2)
Variations in global atmospheric oscillations during the last millennium are simulated using the climate system model FGOALS_gl. The model was driven by reconstructions of both natural forcing (solar variability and volcanic aerosol) and anthropogenic forcing (greenhouse gases and sulfate aerosol). The model results are compared against proxy reconstruction data. The reconstructed North Atlantic Oscillation (NAO) was out of phase with the Pacific Decadal Oscillation (PDO) in the last millennium. During the ... 相似文献
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光学头定位控制由于快速性的要求使得系统产生振荡,影响定位精度.本文应用输入成形方法抑制光头在定位时的振动.通过建立光学头机电系统的数学模型,对于无参数摄动和有参数摄动两种情形分别应用零振荡()和零振荡加微分()两种输入成形控制器进行振动抑制,计算机数值仿真结果表明,该方法对于抑制光学头定位过程中的振动具有较好的效果. 相似文献
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ZOU HaiLin & XU JianXue Institute of Nonlinear Dynamics School of Aerospace Xi'an Jiaotong University Xi'an China 《中国科学:技术科学》2010,(3)
Three main parts of generalized cell mapping are improved for global analysis.A simple method,which is not based on the theory of digraphs,is presented to locate complete self-cycling sets that correspond to attractors and unstable invariant sets involving saddle,unstable periodic orbit and chaotic saddle.Refinement for complete self-cycling sets is developed to locate attractors and unstable invariant sets with high degree of accuracy,which can start with a coarse cell structure.A nonuniformly interior-and... 相似文献
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在高超速情况下,利用直接数值模拟方法,我们研究了真实气体效应(振动由度激发导致比热随温度变化)对槽道湍流影响,并与不考虑振动由度激发情况进行了比较.我们发现振动能激发对统计平均量影响主要体现在温度上,它能够抑制湍流场中平均温度升高;而对于密度,速度及压强影响很小.振动由度激发使原分运动更加剧烈,以致湍流场趋于平坦,表现为脉动值、相关函数及互相关函数减小.同时,由于振动能激发过程是一个吸热过程,因此它对湍流有抑制作用,表现在减小涡量、抑制湍能成及耗散等方面.振动由度激发对于湍流两点相关量、偏斜因及平坦因影响很小. 相似文献
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WU ChuiJie & WANG Liang State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian China Research Center for Fluid Dynamics People's Liberation Army University of Science Technology Nanjing 《中国科学:技术科学》2010,(3)
Numerical simulations of self-propelled swimming of a three dimensional bionic fish and fish school in a viscous fluid are carried out.This is done with the assistance of a parallel software package produced for 3D moving boundary problems.This computational fluid dynamics package combines the adaptive multi-grid finite volume method,the immersed boundary method and VOF (volume of fluid) method.By using the package results of the self-propelled swimming of a 3D bionic fish and fish school in a viscous fluid... 相似文献
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In addition to the hierarchical-structure (H-S) model,this paper further explores the most intensive intermittent structure of Rayleigh-Bénard convection at the high Ra numbers proportional to temperature.With respect to the discovery and by means of the scale,both of Bolgiano,there are two regions of the structure holding the absolute scaling law given by Ching's paper.Through theoretic analysis of data,this paper indicates that the regions act as two local intensive intermittent structures,by which the st... 相似文献
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System dynamics, founded by professor Forrester at Massachusetts Institute of Technology in 1956, is a discipline which analyzes and studies the system of information feedback. Basic views of theories of system dynamics distinctively show its dialectical characteristics. More attention should be paid to the features of complicated nonlinear systems. The model simulation of system dynamics is a kind of structure-function simulation. One of the remarkable advantages of system dynamics is that it can handle problems of high order, nonlinear and multiplefeedback system. 相似文献
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采用常规的二阶声波方程有限差分方法对于非均匀介质进行了数值模拟时 ,其数值模拟精度较低。而采用一阶双曲型标量波动方程 ,则无须对介质的弹性常数进行空间求导。根据Taylor级数展开式 ,推导出了交错网格一阶空间导数的任意偶数阶精度展开式和相应差分系数计算式以及一阶双曲型标量波动方程交错网格任意偶数阶精度差分格式 ,并给出了该差分算法的稳定性条件。用该差分算法对均匀介质模型、非均匀介质模型和Marmousi模型进行了数值模拟试验 ,并与伪谱法进行了对比。结果表明 ,一阶双曲型标量波动方程交错网格高阶差分法的模拟精度与伪谱法的精度非常接近 ,计算效率高 ,且适合于模拟非均匀介质、复杂构造和复杂地质体的地震波场 相似文献