排序方式: 共有8条查询结果,搜索用时 15 毫秒
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Using the principle of diffusion-limited aggregation(DLA),a new model is introduced to simulate the displacement of one fluid by another in porous media.The results agree with experiments.apparently they do not leave out film-flow phenomena.Simultaneously,we also present a new numerical method to treat our results by the lattice Boltzmann method(LBM),All these will be helpful for analysing similar subjects. 相似文献
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物理实验的创新已经引起人们的高度重视,然而,物理实验的更新速度却远远跟不上学生需求的速度。在这种情况下,提出了对物理实验进行创新的“三步走”。第一步,预备阶段,即找出所要创新的物理实验的“重难点”;第二步,设计阶段,即根据重难点,设计出物理创新性实验;第三步,制作与反思阶段,即对所设计的实验进行制作,反思制作过程中出现的问题。“天下无不可创新之物”,对于有瑕疵之物我们都应该并且有能力去改进它。 相似文献
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用加入近邻相互作用势的格子玻尔兹曼方法模拟了表面修饰了去润湿性颗粒的二维管道内流体的流动. 结果显示,管壁的粗糙度、修饰颗粒的润湿性、管内压强以及管内流体黏滞性等都是影响管内流体流速的因素. 在一定压强下,管壁修饰疏水性的颗粒可以明显减小阻力,模拟结果也解释了开采地下油藏时存在启动压力梯度的原因. 相似文献
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The behavior of nano-confined water is expected to be fundamentally different from the behavior of bulk water.At the nanoscale,it is still unclear whether water flows more easily along the convergent direction or the divergent one,and whether a hourglass shape is more convenient than a funnel shape for water molecules to pass through a nanotube.Here,we present an approach to explore these questions by changing the deformation position of a carbon nanotube.The results of our molecular dynamics simulation indicate that the water flux through the nanotube changes significantly when the deformation position moves away from the middle region of the tube.Different from the macroscopic level,we find water flux asymmetry(water flows more easily along the convergent direction than along the divergent one),which plays a key role in a nano water pump driven by a ratchet-like mechanism.We explore the mechanism and calculate the water flux by means of the Fokker-Planck equation and find that our theoretical results are well consistent with the simulation results.Furthermore,the simulation results demonstrate that the effect of deformation location on the water flux will be reduced when the diameter of the nanochannel increases.These findings are helpful for devising water transporters or filters based on carbon nanotubes and understanding the molecular mechanism of biological channels. 相似文献
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通过对人教版初中化学教材与美国初中主流科学教育教材《科学探索者》中金属部分进行分析,从内容构成、组织编排、活动设置等几个维度进行比较。旨在为初中化学教材修订及教师对教学内容的二次加工提供建议。 相似文献
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The factors affecting slip length in Couette geometry flows are analysed by means of a two-phase mesoscopic lattice Boltzmann model including non-ideal fluid-fluid and fluid-wall interactions. The main factors influencing the boundary slip are the strength of interactions between fluid-fluid and fluid-wall particles. Other factors, such as fluid viscosity, bulk pressure may also change the slip length. We find that boundary slip only occurs under a certain density (bulk pressure). If the density is large enough, the slip length will tend to zero. In our simulations, a low density layer near the wall does not need to be postulated a priori but emerges naturally from the underlying non-ideal mesoscopic dynamics. It is the low density layer that induces the boundary slip. The results may be helpful to understand recent experimental observations on the slippage of micro flows. 相似文献
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In this paper, the lattice Boltzmann method is applied to simulate a
dumbbell moving in a pressure-driven flow in a planar channel with
the stress-integration method for the evaluation of hydrodynamic
force acting on the cylinders. The simulation results show that the
dumbbell also has the important feature of the Segr\'e--Silberberg
effect like a particle in a Poiseuille flow. The dumbbell
trajectories, orientations, the cylinders vertical velocities and
angular velocities all reach their equilibrium values separately
independent of their initial positions. It is also found that the
dumbbell equilibrium positions depend on the flow Reynolds number,
blockage ratio and elastic coefficient. This study is expected to be
helpful to understand the dynamics of polymer solutions, polymer
synthesis and reaction, etc. 相似文献
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The rolling massage manipulation is a classic Chinese massage, which is expected to eliminate many diseases. Here the effect of the rolling massage on the particle moving property in the blood vessels under the rolling massage manipulation is studied by the lattice Boltzmann simulation. The simulation results show that the particle moving behaviour depends on the rolling velocity, the distance between particle position and rolling position. The average values, including particle translational velocity and angular velocity, increase as the rolling velocity increases almost linearly. The result is helpful to understand the mechanism of the massage and develop the rolling techniques. 相似文献
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