排序方式: 共有27条查询结果,搜索用时 15 毫秒
1.
广义Maxwell黏弹性流体在两平板间的非定常流动 总被引:2,自引:0,他引:2
将分数阶微积分运算引入Maxwell黏弹性流体的本构方程,研究了黏弹性流体在两平板问的非定常流动.对于广义Maxwell黏弹性流体的分数阶导数模型,导出了对时间具有分数阶导数的特殊运动方程,利用分数阶微积分的Laplace变换理论,得到了流动的解析解. 相似文献
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A numerical analysis of flow and concentration fields of macromolecules in a, slightly curved blood vessel was carried out.
Based on these results, the effect of the bifurcation of a flow on the mass transport in a curved blood vessel was discussed.
The macromolecules turned out to be easier to deposit in the inner part of the curved blood vessel near the critical Dean
number. Once the Dean number is higher than the critical number, the bifurcation of the flow appears. This bifurcation can
prevent macromolecules from concentrating in the inner part of the curved blood vessel. This result is helpful for understanding
the possible correlations between the blood dynamics and atherosclerosis.
The project supported by National Natural Science Foundation of China (10002003), JSPS Postdoctoral Fellowship for Foreign
Researcher and Foundation for University Teachers, the Ministry of Education 相似文献
3.
提出广义分数阶单元网络, 取消了Schiessel等人所提出的分数阶单元法对参数的限制, 增加了“协调方程”, 将模型解的构造扩充到广义函数空间, 使其包含更多的具有明显物理意义的解. 应用并发展了离散求逆Laplace变换的方法, 给出了模型方程的广义解. 讨论了广义分数阶单元网络Zener, Poyinting-Thomson模型. 结果表明, 有关黏弹性材料本构方程经典的和前人所得的经典整数阶和分数阶单参数模型的所有结果均可作为本文的特例而被包括. 相似文献
4.
Theoretical analysis of the velocity field, stress field and vortex sheet of generalized second order fluid with fractional anomalous diffusion 总被引:1,自引:0,他引:1
The velocity field of generalized second order fluid with fractional anomalous diiusion caused by a plate moving impulsively
in its own plane is investigated and the anomalous diffusion problems of the stress field and vortex sheet caused by this
process are studied. Many previous and classical results can be considered as particular cases of this paper, such as the
solutions of the fractional diffusion equations obtained by Wyss; the classical Rayleigh’s time-space similarity solution;
the relationship between stress field and velocity field obtained by Bagley and co-worker and Podlubny’s results on the fractional
motion equation of a plate. In addition, a lot of significant results also are obtained. For example, the necessary condition
for causing the vortex sheet is that the time fractional diffusion index β must be greater than that of generalized second
order fluid α; the establiihment of the vorticity distribution function depends on the time history of the velocity profile
at a given point, and the time history can be described by the fractional calculus. 相似文献
5.
Stokes' first problem has been investigated for a Maxwell fluid in a porous
half-space for gaining insight into the effect of viscoelasticity on the start-up
flow in a porous medium. An exact solution was obtained by using the Fourier sine
transform. It was found that at large values of the relaxation time the velocity
overshoot occurs obviously and the system exhibits viscoelastic behaviours. On the
other hand, for short relaxation time the velocity overshoot disappears and the
system exhibits viscous behaviours. A critical value of the relaxation time was
obtained for the emergence of the velocity overshoot. Furthermore, it was found that
the velocity overshoot is caused by both the viscoelasticity of the Maxwell fluid
and the Darcy resistance resulting from the structure of the micropore in the porous
medium. 相似文献
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Intherealmofchemoreception,thesenseofsmellremainsoneofthemostobscureprovinces.Morerecently,theartificialelectricnoseliesgoodprospectforvariableaspectssuchaspublicsecurity,nationaldefenceandforbiddennarcoticswiththedevelopmentoftissueengineeringandbio… 相似文献
10.
基于修正的Darcy模型, 介绍了多孔介质内黏弹性流体热对流稳定性研究的现状和主要进展. 通过线性稳定性理论, 分析计算多孔介质几何形状(水平多孔介质层、多孔圆柱以及多孔方腔)、热边界条件(底部等温加热、底部等热流加热、底部对流换热以及顶部自由开口边界)、黏弹性流体的流动模型(Darcy-Jeffrey, Darcy-Brinkman-Oldroyd以及Darcy-Brinkman -Maxwell模型)、局部热非平衡效应以及旋转效应对黏弹性流体热对流失稳的临界Rayleigh数的影响. 利用弱非线性分析方法, 揭示失稳临界点附近热对流流动的分叉情况, 以及失稳临界点附近黏弹性流体换热Nusselt数的解析表达式. 采用数值模拟方法, 研究高Rayleigh数下黏弹性流体换热Nusselt数和流场的演化规律,分析各参数对黏弹性流体热对流失稳和对流换热速率的影响.主要结果:(1)流体的黏弹性能够促进振荡对流的发生;(2)旋转效应、流体与多孔介质间的传热能够抑制黏弹性流体的热对流失稳;(3)在临界Rayleigh数附近,静态对流分叉解是超临界稳定的, 而振荡对流分叉可能是超临界或者亚临界的,主要取决于流体的黏弹性参数、Prandtl数以及Darcy数;(4)随着Rayleigh数的增加,热对流的流场从单个涡胞逐渐演化为多个不规则单元涡胞, 最后发展为混沌状态. 相似文献