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NUMERICAL SIMULATION OF NANOPARTICLE COAGULATION IN A poiseuille flow VIA A MOMENT METHOD

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Journal of Hydrodynamics 2008年第1期20卷 1-9页

作者： LIU Song LIN Jian-zhong State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China China Jiiiang University Hangzhou 310018 China

Numerical simulations of coagulating nano-scale aerosols in a two dimensional poiseuille flow between fixed plates are performed. Evolution of the particle field is obtained by utilizing a moment method to approximate the aerosol general dynamic equation. A moment method is used, which assumes a lognormal function for the particle size distribution and requires knowledge of the first three moments. A Damk？hler number is defined to represent the ratio of the convection time scale to the coagulation time scale. Simulations are performed based on three Reynolds numbers, 100, 500 and 1000, and on three initial particle volume fractions corresponding to Damk？hler numbers 0.1, 0.2 and 1.0. Spatio-temporal evolution of the first three moments along with the geometric mean volume and standard deviation are discussed.

关键词： nanoparticle Coagulation moment method poiseuille flow

Algorithm for transient growth of perturbations in channel poiseuille flow

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Applied Mathematics and Mechanics(English Edition) 2017年第11期38卷 1635-1650页

作者： Jianlei ZHANG Gang DONG Yi LI National Key Laboratory of Transient Physics Nanjing University of Science and Technology School of Mathematics and Statistics University of Sheffield

This study develops a direct optimal growth algorithm for three-dimensional transient growth analysis of perturbations in channel flows which are globally stable but locally unstable. Different from traditional non-modal methods based on the Orr- Somrnerfeld and Squire （OSS） equations that assume simple base flows, this algorithm can be applied to arbitrarily complex base flows. In the proposed algorithm, a re- orthogonalization Arnoldi method is used to improve orthogonality of the orthogonal basis of the Krylov subspace generated by solving the linearized forward and adjoint Navier-Stokes （N-S） equations. The linearized adjoint N-S equations with the specific boundary conditions for the channel are derived, and a new convergence criterion is pro- posed. The algorithm is then applied to a one-dimensional base flow （the plane poiseuille flow） and a two-dimensional base flow （the plane poiseuille flow with a low-speed streak） in a channel. For one-dimensional cases, the effects of the spanwise width of the chan- nel and the Reynolds number on the transient growth of perturbations are studied. For two-dimensional cases, the effect of strength of initial low-speed streak is discussed. The presence of the streak in the plane poiseuille flow leads to a larger and quicker growth of the perturbations than that in the one-dimensional case. For both cases, the results show that an optimal flow field leading to the largest growth of perturbations is character- ized by high- and low-speed streaks and the corresponding streamwise vortical structures. The lift-up mechanism that induces the transient growth of perturbations is discussed. The performance of the re-orthogonalization Arnoldi technique in the algorithm for both one- and two-dimensional base flows is demonstrated, and the algorithm is validated by comparing the results with those obtained from the OSS equations method and the cross- check method.

关键词： transient growth poiseuille flow Arnoldi method Krylov subspace adjoint equation

Role of Hydrodynamic Interactions in the Deformation of Star Polymers in poiseuille flow

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Chinese Journal of Polymer Science 2020年第4期38卷 363-370,I0006页

作者： Zhen-Yue Yang Xiao-Fei Tian Li-Jun Liu Ji-Zhong Chen State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Chinese Academy of Sciences Beijing 100049China

Stretching polymer in fluid flow is a vital process for studying and utilizing the physical properties of these molecules,such as DNA linearization in nanofluidic *** studied the role of hydrodynamic interactions(His)in stretching a free star polymer in poiseuille flow through a tube using mesoscale hydrodynamic *** increasing the flow strength,star polymers migrate toward the centerline of tube due to His,whereas toward the tube wall in the absence of *** analyzing the end monomer distribution and the perturbed flow around the star polymer,we found that the polymer acts like a shield against the flow,leading to additional hydrodynamic drag forces that compress the arm chains in the front of the star center toward the tube axis and lift the arm chai ns at the back toward the tube *** balanced hydrodynamic forces freeze the polymer into a trumpet structure,where the arm chains maintain a steady strongly stretched state at high flow *** contrast,the polymer displays remarkably large conformational change when switching off *** simulation results explained the coupling between His and the structure of star polymers in poiseuille flow.

关键词： Hydrodynamic interactions Star polymer poiseuille flow Migration

Experimental study of an ellipsoidal particle in tube poiseuille flow

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Journal of Hydrodynamics 2020年第3期32卷 616-622页

作者： Yuan-feng Cui Xiang-ting Chang Hai-bo Huang Department of Modern Mechanics University of Science and Technology of ChinaHefei 230026China

Behaviors of a prolate ellipsoid inside circular tube poiseuille flow are studied experimentally. In the study, Reynolds number Re ∈ (100,700) and the confinement ratio D/A ∈ (1.2,2.8) are considered, where D is the diameter of the tube and A is the length of the major axis of the ellipsoid. Two typical stable motion modes are identified, namely, the horizontal, and inclined modes. Then another inclined mode (inclined mode II) is found at high Reynolds number (Re ∈ (1000,3200)) and small D/A, and the inclined angle of ellipsoid increases with the increase of Re. The possible mechanism is explained. Our experiment shows that the lagging velocity U increases as Re increases. Further numerical analysis using FLUENT shows that due to the increase of U, the moment acting on the particle would make the inclined angle of the particle increase.

关键词： Ellipsoidal particle poiseuille flow circular tube experiment

INVESTIGATION OF INFLUENCE OF WETTABILITY ON poiseuille flow VIA MOLECULAR DYNAMICS SIMULATION

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Journal of Hydrodynamics 2010年第4期22卷 513-517页

作者： SONG Fu-quan WANG Jian-dong College of Mathematics Physics and Information Engineering Zhejiang Normal University Jinhua 321004

In this article,the influence of wettability on a liquid flow between two parallel plane walls were studied by using Non-Equilibrium Molecular Dynamics（NEMD） *** wettability of the solid surfaces can be described as the contact *** liquid flow rate,the slip velocity and the slip length which are affected by the contact angle were *** results show that the boundary condition at a microscopic level is different from a ＂no-slip＂ condition at a macroscopic *** exits a slippage of a liquid flow for the hydrophobic boundary and an external force is needed to overcome threshold pressure for the hydrophilic *** the orderly layered distributions of the liquid particles near the hydrophilic surface vary from a place near the hydrophobic *** study indicates that the surface wettability plays a significant role on possibilities of forming a viscous layer and the direct slip at the solid *** resistance of liquid flow can be decreased by changing the wettability of boundary surface.

关键词： molecular dynamics simulation poiseuille flow hydrophilic surface hydrophobic surface velocity slippage

ANOMALOUS DIFFUSION IN FINITE LENGTH FINGERS COMB FRAME WITH THE EFFECTS OF TIME AND SPACE RIESZ FRACTIONAL CATTANEO-CHRISTOV FLUX AND poiseuille flow

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Journal of Computational Mathematics 2018年第4期36卷 563-578页

作者： Lin Liu Liancun Zheng Fawang Liu Xinxin Zhang School of Mathematics and Physics and School of Energy and Environmental Engineering University of Science and Technology Beijing Beijing 100083 China School of Energy and Environmental Engineering Queensland University of Technology GPO Box 2434 Brisbane Qld. 4001 Australia School of Mechanical Engineering University of Science and Technology Beijing Beijing 100083 China

This paper presents an investigation on the anomalous diffusion in finite length fingers comb frame, the time and space Riesz fractional Cattaneo-Christov flux is introduced with the Oldroyds＇ upper convective derivative and the effect of poiseuille flow is also taken into account. Formulated governing equation possesses the coexisting characteristics of parabolicity and hyperbolicity. Numerical solution is obtained by the Ll-scheme and shifted Griinwald formulae, which is verified by introducing a source item to construct an exact solution. The effects, such as time and space fractional parameters, relaxation parameter and the ratio of the pressure gradient and viscosity coefficient, on the spatial and temporal evolution of particles distribution and dynamic characteristics are shown graphically and analyzed in detail.

关键词： Anomalous diffusion Cattaneo-Christov flux Fractional derivative poiseuille flow Distribution

Design of poiseuille flow Controllers Using the Method of Inequalities

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International Journal of Automation and computing 2009年第1期6卷 14-21页

作者： John McKernan James F. Whidborne George Papadakis Department of Mechanical Engineering King s College London Strand Department of Aerospace Sciences Cranfield University

This paper investigates the use of the method of inequalities （MoI） to design output-feedback compensators for the problem of the control of instabilities in a laminar plane poiseuille flow. In common with many flows, the dynamics of streamwise vortices in plane poiseuille flow are very non-normal. Consequently, small perturbations grow rapidly with a large transient that may trigger nonlinearities and lead to turbulence even though such perturbations would, in a linear flow model, eventually decay. Such a system can be described as a conditionally linear system. The sensitivity is measured using the maximum transient energy growth, which is widely used in the fluid dynamics community. The paper considers two approaches. In the first approach, the MoI is used to design low-order proportional and proportional-integral （PI） controllers. In the second one, the MoI is combined with McFarlane and Glover＇s H∞ loop-shaping design procedure in a mixed-optimization approach.

关键词： Transient energy growth transient behaviour flow control poiseuille flow method of inequalities (MoI) mixed opti-mization H∞-optimization.

Numerical Simulation of Interaction Between Red Blood Cell with Surrounding Fluid in poiseuille flow

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Advances in Applied Mathematics and Mechanics 2018年第1期10卷 62-76页

作者： Reza Esmaily Nader Pourmahmoud Iraj Mirzaee Department of Mechanical Engineering Urmia University PardisUrmiaIran

In this research,motion and deformation of a red blood cell(RBC)in a microchannel with stenosis is investigated by combined Lattice Boltzmann-Immersed Boundary *** fluid flow occurs due to the pressure difference between the inlet and the outlet of the *** immersed boundary algorithm guaranteed that there is no relative velocity between the RBC and ***,mass transfer along the immersed border does not *** can be seen that the healthy RBC has more deformation and passes the stenosis easier while the sick one passes the stenosis with less deformation and returns to its initial state *** the pressure gradient(i.e.,increasing Reynolds number)would cause more deformation of the *** is found that a healthy RBC moves faster than a sick one along the *** pressure increases due to the presence of stenosis and low deformable *** is the reason of many serious diseases including cardiovascular *** results of this paper were compared to the previous valid results and good agreements were observed.

关键词： Interaction poiseuille flow lattice Boltzmann method numerical simulation

Numerical Validation of Brenner’s Hydrodynamic Model by Force Driven poiseuille flow

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Advances in Applied Mathematics and Mechanics 2009年第3期1卷 391-401页

作者： Zhaoli Guo Kun Xu National Laboratory of Coal Combustion Huazhong University of Science and TechnologyWuhan 430074P.R.China Department of Mathematics Hong Kong University of Science and TechnologyKowloonHong KongChina

Recently Brenner[Physica A 349,60(2005)]proposed a modified NavierStokes set of *** on some theoretical arguments and some limited experiments,the model is expected to be able to describe flows with a finite Knudsen *** this work,we apply this model to the plane poiseuille flow driven by a force,and compare the results with the Direct Simulation Monte Carlo(DSMC)*** is found that Brenner’s model is inadequate for flows with a finite Knudsen number.

关键词： Non-equilibrium hydrodynamic model poiseuille flow