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建立了研究炸药爆轰驱动条件下金属材料Rayleigh-Taylor不稳定性问题的实验技术和数值模拟方法。利用该实验技术和数值模拟方法研究了炸药爆轰驱动条件下,铝飞层界面Rayleigh-Taylor不稳定性增长规律,数值模拟显示界面扰动振幅以指数规律增长。数值模拟结果和实验定性相符,但是定量相比有较大差别,原因是高压高应变率加载条件下铝的强度增强,而数值模拟时所采用的SG本构模型在这样的加载条件下低估了铝的强度而导致对扰动增长致稳作用不足。然后在数值模拟中,通过改变材料的初始剪切模量和初始屈服强度,发现在一定范围内,初始剪切模量对材料动态屈服强度没有影响,而初始屈服强度增大可以明显提高材料的动态屈服强度,达到抑制扰动增长的目的,表明材料屈服强度主导界面扰动增长。 相似文献
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数值模拟研究了钾离子电流对心脏系统中的螺旋波的影响,通过适当减小GK1可以有效抑制心脏中的螺旋波。抑制的物理机制为适当减小GK1可以抑制各种离子电流的激发,导致螺旋波无法自我维持。 相似文献
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The geophysical quantitative excitation on seasonal polar wobble of Earth Rotation has not been well achieved so far. The
atmospheric, hydrologic and oceanic angular momentum variations are investigated from monthly values simulated by a coupled
ocean-atmosphere general circulation model. The simulated equatorial AAM functions agree well with that from the JMA operational
analysis in 90°:E direction, but disagree along Greenwich meridian. As for the annual cycle, not only the hydrologic and oceanic
excitations partly match the residuals between geodetic functions of polar wobble and JMA AAM functions, but also the combinations
with NCEP and JMA analysis AAM functions are better than those estimated from NCAR-CSM1 climate model. 相似文献
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为适应新时期基础教育课程改革对物理类师范生课程设置的要求,提出了重视物理学科基础课、加强学生自主学习能力和研究能力的培养、加强教育实践课程、整体优化我国物理师范类课程体系的内部结构,以构建适应新时期基础课改要求的高师院校物理类师范生课程设置模式。 相似文献
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Physical analysis on improving the recovery accuracy of the Earth’s gravity field by a combination of satellite observations in along-track and cross-track directions 总被引:1,自引:0,他引:1 下载免费PDF全文
The physical investigations on the accuracy improvement to the measurement of the Earth's gravity field recovery are carried out based on the next-generation Pendulum-A/B out-of-plane twin-satellite formation in this paper. Firstly, the Earth's gravity field complete up to degree and order 100 is, respectively, recovered by the collinear and pendulum satellite formations using the orbital parameters of the satellite and the matching accuracies of key payloads from the twin GRACE satellites. The research results show that the accuracy of the Earth's gravity field model from the Pendulum-A/B satellite formation is about two times higher than from the collinear satellite formation, and the further improvement of the determination accuracy of the Earth's gravity field model is feasible by the next-generation Pendulum-A/B out-of-plane twin-satellite formation. Secondly, the Earth's gravity field from Pendulum-A/B complete up to degree and order 100 is accurately recovered based on the orbital parameters of the satellite (e.g., an orbital altitude of 400 km, an intersatellite range of 100 km, an orbital inclination of 89° and an orbital eccentricity of 0.001), the matching accuracies of space- borne instruments (e.g. 10-6 m in the intersatellite range, 10-3 m in the orbital position, 10-6 m/s in orbital velocity, and 10-11 m/s2 in non-conservative force), an observation time of 30 days and a sampling interval of 10 s. The measurement accuracy of the Earth's gravity field from the next-generation Pendulum-A/B out-of-plane twin-satellite formation is full of promise for being improved by about l0 times compared with that from the current GRACE satellite formation. Finally, the physical requirements for the next-generation Pendulum-A/B out-of-plane twin-satellite formation are analyzed, and it is proposed that the satellite orbital altitude be preferably designed to be close to 400±50 km and the matching precision of key sensors from the Pendulum-A/B mission be about one order of magnitude higher tha 相似文献
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研究了一种Euler-Lagrange耦合数值方法——GEL(Ghost-fluid Euler-Lagrange)方法,编写了GEL二维计算程序。 相似文献
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利用可压缩多介质黏性流动和湍流大涡模拟代码(MVFT),在超算平台上对"反尖端"界面不稳定性及其诱发的湍流混合问题进行了大规模三维数值模拟分析。数值模拟结果清晰地显示了冲击波加载界面后分解产生的冲击波、稀疏波、压缩波及其在SF6气体中的运动和相互作用,以及波多次加载界面的复杂过程,波和界面的每一次作用都会加速湍流混合区的发展和物质混合。"反尖端"界面受冲击波加载后发生反相而形成典型的大尺度壁面气泡和中心轴尖钉结构,该大尺度结构基本确定了湍流混合区的平均几何特征和包络范围而不依赖计算网格。高分辨率的计算网格下,捕捉到了更精细的小尺度湍涡结构和更强的湍流脉动,显示了湍流混合区所具有的复杂结构和特征。 相似文献
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A contrastive study on the influences of radial and three-dimensional satellite gravity gradiometry on the accuracy of the Earth's gravitational field recovery 下载免费PDF全文
The accuracy of the Earth’s gravitational field measured from the gravity field and steady-state ocean circulation explorer(GOCE),up to 250 degrees,influenced by the radial gravity gradient V zz and three-dimensional gravity gradient V ij from the satellite gravity gradiometry(SGG) are contrastively demonstrated based on the analytical error model and numerical simulation,respectively.Firstly,the new analytical error model of the cumulative geoid height,influenced by the radial gravity gradient V zz and three-dimensional gravity gradient V ij are established,respectively.In 250 degrees,the GOCE cumulative geoid height error measured by the radial gravity gradient V zz is about 2 1/2 times higher than that measured by the three-dimensional gravity gradient V ij.Secondly,the Earth’s gravitational field from GOCE completely up to 250 degrees is recovered using the radial gravity gradient V zz and three-dimensional gravity gradient V ij by numerical simulation,respectively.The study results show that when the measurement error of the gravity gradient is 3×10 12 /s 2,the cumulative geoid height errors using the radial gravity gradient V zz and three-dimensional gravity gradient V ij are 12.319 cm and 9.295 cm at 250 degrees,respectively.The accuracy of the cumulative geoid height using the three-dimensional gravity gradient V ij is improved by 30%-40% on average compared with that using the radial gravity gradient V zz in 250 degrees.Finally,by mutual verification of the analytical error model and numerical simulation,the orders of magnitude from the accuracies of the Earth’s gravitational field recovery make no substantial differences based on the radial and three-dimensional gravity gradients,respectively.Therefore,it is feasible to develop in advance a radial cold-atom interferometric gradiometer with a measurement accuracy of 10 13 /s 2-10 15 /s 2 for precisely producing the next-generation GOCE Follow-On Earth gravity field model with a high spatial resolution. 相似文献