This page has only limited features, please log in for full access.
Jianzhong Lin is a professor in the department of mechanics at Zhejiang University, China. He received his PhD degree from Peking University in 1991. His scientific interests are multiphase fluid flows, nanofluids, micro fluid dynamics, turbulence and fluid machinery. His works were funded by more than 40 research projects. So far he has published more than 600 academic papers and won more than ten science and technology awards. He was the associate editor of International Journal of Multiphase flow, and is currently serving as the chief editor of Mechanics in Engineering, associate editor of Applied Mathematics and Mechanics, associate editor of Journal of Drainage and Irrigation Machinery Engineering, and editorial board members of more than ten academic journals.
Multiphase flow with self-driven particles is ubiquitous and complex. Exploring the flow properties has both important academic meaning and engineering value. This review emphasizes some recent studies on multiphase flow with self-driven particles: the hydrodynamic interactions between self-propelled/self-rotary particles and passive particles; the aggregation, phase separation and sedimentation of squirmers; the influence of rheological properties on its motion; and the kinematic characteristics of axisymmetric squirmers. Finally, some open problems, challenges, and future directions are highlighted.
Chen Liu; Jianzhong Lin. A Review on the Some Issues of Multiphase Flow with Self-Driven Particles. Applied Sciences 2021, 11, 7361 .
AMA StyleChen Liu, Jianzhong Lin. A Review on the Some Issues of Multiphase Flow with Self-Driven Particles. Applied Sciences. 2021; 11 (16):7361.
Chicago/Turabian StyleChen Liu; Jianzhong Lin. 2021. "A Review on the Some Issues of Multiphase Flow with Self-Driven Particles." Applied Sciences 11, no. 16: 7361.
An immersed boundary-lattice Boltzmann (IB-LB) method is employed to investigate the migration of a two-dimensional cylindrical micro-swimmer in a channel flow. The swimming Reynolds numbers (Res), the flow Reynolds numbers (Rep), and the blockage ratios (κ) are respectively set being from 0.05 to 2.0, 40 to 160, and 0.11 to 0.5 in the simulations. A two-dimensional archetypal self-propelled model generating tangential surface waves is employed to mimic a micro-swimmer with different Res swimming in the presence of a channel flow with different Rep and κ, finding four typical locomotion modes, namely, the horizontal mode, the attracted oscillatory mode, the oscillatory mode, and the chaotic mode. At Rep = 100 and κ = 0.25, the squirmer displays an oscillatory motion even though at a lower Res (Res = 0.05), indicating a different migration behavior from that of a passive particle; With increasing Res, the horizontal or the attracted oscillatory mode develops to the oscillatory or the chaotic mode, showing a tendency of motion symmetrical concerning the centreline. On increasing Rep with Res = 0.1 and κ = 0.25, the squirmer with a lower swimming intensity |β| ≤ 1 maintains the attracted oscillatory mode, whereas the pusher (propelled from the rear) with β = −3 and the puller with β = 3 (propelled from the front) develop to the attracted oscillatory mode from the oscillatory and horizontal modes, respectively. At Rep = 100 and Res = 0.1, the squirmers with −3 ≤ β ≤ 0 and the puller with β = 5 respectively maintain the attracted oscillatory and the horizontal modes regardless of κ; On increasing κ, the horizontal mode for the pullers with 1 ≤ β ≤ 3 and the attracted oscillatory mode for the pusher with β = −5 develop to the attracted oscillatory and oscillatory modes, respectively. The transport velocity of the squirmer is also studied with the variations of Res, Rep, and κ, obtaining a maximum value for the neutral squirmer at Res = 1.5, Rep = 100, and κ = 0.25.
Zhenyu Ouyang; Jianzhong Lin. Migration of a micro-swimmer in a channel flow. Powder Technology 2021, 392, 587 -600.
AMA StyleZhenyu Ouyang, Jianzhong Lin. Migration of a micro-swimmer in a channel flow. Powder Technology. 2021; 392 ():587-600.
Chicago/Turabian StyleZhenyu Ouyang; Jianzhong Lin. 2021. "Migration of a micro-swimmer in a channel flow." Powder Technology 392, no. : 587-600.
Effect of rheological property on the migration and alignment of three interacting particles in Poiseuille flow of Giesekus fluids is studied with the direct-forcing fictitious domain method for the Weissenberg number (Wi) ranging from 0.1 to 1.5, the mobility parameter ranging from 0.1 to 0.7, the ratio of particle diameter to channel height ranging from 0.2 to 0.4, the ratio of the solvent viscosity to the total viscosity being 0.3 and the initial distance (y0) of particles from the centerline ranging from 0 to 0.2. The results showed that the effect of y0 on the migration and alignment of particles is significant. The variation of off-centerline (y0 ≠ 0) particle spacing is completely different from that of on-centerline (y0 = 0) particle spacing. As the initial vertical distance y0 increased, the various types of particle spacing are more diversified. For the off-centerline particle, the change of particle spacing is mainly concentrated in the process of cross-flow migration. Additionally, the polymer extension is proportional to both the Weissenberg number and confinement ratio. The bigger the Wi and confinement ratio is, the bigger the increment of spacing is. The memory of shear-thinning is responsible for the reduction of d1. Furthermore, the particles migrate abnormally due to the interparticle interaction.
Bing-Rui Liu; Jian-Zhong Lin; Xiao-Ke Ku. Migration and Alignment of Three Interacting Particles in Poiseuille Flow of Giesekus Fluids. Fluids 2021, 6, 218 .
AMA StyleBing-Rui Liu, Jian-Zhong Lin, Xiao-Ke Ku. Migration and Alignment of Three Interacting Particles in Poiseuille Flow of Giesekus Fluids. Fluids. 2021; 6 (6):218.
Chicago/Turabian StyleBing-Rui Liu; Jian-Zhong Lin; Xiao-Ke Ku. 2021. "Migration and Alignment of Three Interacting Particles in Poiseuille Flow of Giesekus Fluids." Fluids 6, no. 6: 218.
Flow and heat transfer property of Oldroyd-B-fluid-based nanofluids containing cylindrical particles are studied in a pipe with circular cross-section in the range of Reynolds number (Re) from 100 to 2000, Weissenberg number (We) from 0.1 to 2, particle aspect ratio (β) from 2 to 16 and particle volume concentration (Φ) from 0.1% to 2.5%. The motion equation of Oldroyd-B fluid with particles, the equation for probability density function of particle orientation and convection-diffusion equation for particles are solved numerically. The numerical method used in the simulation is validated by comparing with the available results. The effects of Re, We, β and Φ on the friction factor (f), Nusselt number (Nu) and ratio of energy performance evaluation criterion (PEC t /PEC f ) for Oldroyd-B-fluid-based nanofluids to that for Oldroyd-B fluids are discussed. The results showed that the values of f and Nu of Oldroyd-B-fluid-based nanofluids are larger than that of water-based nanofluids and that of pure Oldroyd-B fluids. The values of f increase with increasing Re, We and Φ, but with decreasing β. The values of Nu and PEC t /PEC f are enhanced with increasing Re, We, β and Φ. The increase of f is larger than that of Nu at lower Re, but is less than that of Nu at higher Re. It is more effective to use Oldroyd-B-fluid-based nanofluids with cylindrical nanoparticles to improve the heat transfer at the conditions of higher Re, We, β and Φ. Finally, the correlation formula of PEC t /PEC f as a function of Re, We, β and Φ is derived.
Wenqian Lin; Peijie Zhang; Jianzhong Lin. Flow and Heat Transfer Property of Oldroyd-B-Fluid-Based Nanofluids Containing Cylindrical Particles in a Pipe. Processes 2021, 9, 647 .
AMA StyleWenqian Lin, Peijie Zhang, Jianzhong Lin. Flow and Heat Transfer Property of Oldroyd-B-Fluid-Based Nanofluids Containing Cylindrical Particles in a Pipe. Processes. 2021; 9 (4):647.
Chicago/Turabian StyleWenqian Lin; Peijie Zhang; Jianzhong Lin. 2021. "Flow and Heat Transfer Property of Oldroyd-B-Fluid-Based Nanofluids Containing Cylindrical Particles in a Pipe." Processes 9, no. 4: 647.
The Reynolds-averaged general dynamic equation (RAGDE) for the nanoparticle size distribution function is derived, including the contribution to particle coagulation resulting from the fluctuating concentration. The equation together with that of a turbulent gas flow is solved numerically in the turbulent flow of a ventilation chamber with a jet on the wall based on the proposed model relating the fluctuating coagulation to the gradient of mean concentration. Some results are compared with the experimental data. The results show that the proposed model relating the fluctuating coagulation to the gradient of mean concentration is reasonable, and it is necessary to consider the contribution to coagulation resulting from the fluctuating concentration in such a flow. The changes of the particle number concentration M 0 and the geometric mean diameter d g are more obvious in the core area of the jet, but less obvious in other areas. With the increase in the initial particle number concentration m 00, the values of M 0 and the standard deviation of the particle size σ decrease, but the value of d g increases. The decrease in the initial particle diameter leads to the reduction of M 0 and σ, and the increase in d g. With the increase in the Reynolds number, particles have few chances of collision, and hence the coagulation rate is reduced, leading to the increase in M 0 and σ, and the decrease in d g.
Ruifang Shi; Jianzhong Lin; Hailin Yang; Mingzhou Yu. Distribution of non-spherical nanoparticles in turbulent flow of ventilation chamber considering fluctuating particle number density. Applied Mathematics and Mechanics 2021, 42, 317 -330.
AMA StyleRuifang Shi, Jianzhong Lin, Hailin Yang, Mingzhou Yu. Distribution of non-spherical nanoparticles in turbulent flow of ventilation chamber considering fluctuating particle number density. Applied Mathematics and Mechanics. 2021; 42 (3):317-330.
Chicago/Turabian StyleRuifang Shi; Jianzhong Lin; Hailin Yang; Mingzhou Yu. 2021. "Distribution of non-spherical nanoparticles in turbulent flow of ventilation chamber considering fluctuating particle number density." Applied Mathematics and Mechanics 42, no. 3: 317-330.
Particle migration induced by hydrodynamic interparticle interaction in a Poiseuille flow of Giesekus viscoelastic fluid is studied numerically using the direct forcing/fictitious domain method with Weissenberg number 0.1 ≤ Wi ≤ 1.5, mobility parameter 0.1 ≤ α ≤ 0.7, viscosity ratio 0.1 ≤ β ≤ 0.7, block ratio 0.2 ≤ ε ≤ 0.4, initial interparticle spacing 0.1 ≤ s ≤ 2.0, and initial vertical position 0.1 ≤ y0 ≤ 0.2. The method is validated by comparing the present results with previous numerical results. The effects of Wi, α, β, ε, s and y0 on the particle migration are analyzed. The results showed that a particle tends to move toward the wall with the increases of the elastic effect of the fluid, shear thinning effect, solvent viscosity and block ratio. For three particles in initial parallel arrangement, the trajectory of two particles on the edge is obviously different from that of a single particle. A single particle would move toward the centerline at a definite y0. However, for the case of three particles at a same y0, the upstream particle first migrates a distance toward the wall and then return toward the centerline, while downstream particle migrates quickly to the centerline. This is called abnormal migration. The phenomenon of abnormal migration disappears when the initial interparticle spacing is large enough, and is more obvious when the initial vertical position of particles is close to the wall. The phenomenon of abnormal migration tends to be obvious with the increases of the shear thinning effect, solvent viscosity and the block ratio, but with the decrease of elastic effect of the fluid.
Bingrui Liu; Jianzhong Lin; Xiaoke Ku. Particle migration induced by hydrodynamic interparticle interaction in the Poiseuille flow of a Giesekus fluid. Journal of the Brazilian Society of Mechanical Sciences and Engineering 2021, 43, 1 -12.
AMA StyleBingrui Liu, Jianzhong Lin, Xiaoke Ku. Particle migration induced by hydrodynamic interparticle interaction in the Poiseuille flow of a Giesekus fluid. Journal of the Brazilian Society of Mechanical Sciences and Engineering. 2021; 43 (2):1-12.
Chicago/Turabian StyleBingrui Liu; Jianzhong Lin; Xiaoke Ku. 2021. "Particle migration induced by hydrodynamic interparticle interaction in the Poiseuille flow of a Giesekus fluid." Journal of the Brazilian Society of Mechanical Sciences and Engineering 43, no. 2: 1-12.
Distribution and deposition of cylindrical nanoparticles in a turbulent pipe flow are investigated numerically. The equations of turbulent flow including the effect of particles are solved together with the mean equations of the particle number density and the probability density function for particle orientation including the combined effect of Brownian and turbulent diffusion. The results show that the distribution of the particle concentration on the cross-section becomes non-uniform along the flow direction, and the non-uniformity is reduced with the increases of the particle aspect ratio and Reynolds number. More and more particles will align with their major axis near to the flow direction, and this phenomenon becomes more obvious with increasing the particle aspect ratio and with decreasing the Reynolds number. The particles in the near-wall region are aligned with the flow direction obviously, and only a slight preferential orientation is observed in the vicinity of pipe’s center. The penetration efficiency of particle decreases with increasing the particle aspect ratio, Reynolds number and pipe length-to-diameter ratio. Finally, the relationship between the penetration efficiency of particle and related synthetic parameters is established based on the numerical data.
Wenqian Lin; Ruifang Shi; Jianzhong Lin. Distribution and Deposition of Cylindrical Nanoparticles in a Turbulent Pipe Flow. Applied Sciences 2021, 11, 962 .
AMA StyleWenqian Lin, Ruifang Shi, Jianzhong Lin. Distribution and Deposition of Cylindrical Nanoparticles in a Turbulent Pipe Flow. Applied Sciences. 2021; 11 (3):962.
Chicago/Turabian StyleWenqian Lin; Ruifang Shi; Jianzhong Lin. 2021. "Distribution and Deposition of Cylindrical Nanoparticles in a Turbulent Pipe Flow." Applied Sciences 11, no. 3: 962.
The formation of self-organizing single-line particle train in a channel flow of a power-law fluid is studied using the lattice Boltzmann method with power-law index 0.6≤n≤1.2, particle volume concentration 0.8%≤Φ≤ 6.4%, Reynolds number 10≤Re≤100, and blockage ratio 0.2≤n≤0.4. The numerical method is validated by comparing the present results with the previous ones. The effect n, Φ, Re and k on the interparticle spacing and parallelism of particle train is discussed. The results showed that the randomly distributed particles would migrate towards the vicinity of the equilibrium position and form the ordered particle train in the power-law fluid. The equilibrium position of particles is closer to the channel centerline in the shear-thickening fluid than that in the Newtonian fluid and shear-thinning fluid. The particles are not perfectly parallel in the equilibrium position, hence IH is used to describe the inclination of the line linking the equilibrium position of each particle. When self-organizing single-line particle train is formed, the particle train has a better parallelism and hence benefit for particle focusing in the shear-thickening fluid at high Φ, low Re and small k. Meanwhile, the interparticle spacing is the largest and hence benefit for particle separation in the shear-thinning fluid at low Φ, low Re and small k.
Xiao Hu; Jianzhong Lin; Dongmei Chen; Xiaoke Ku. Dynamics of self-organizing single-line particle trains in the channel flow of a power-law fluid. Chinese Journal of Chemical Engineering 2020, 34, 12 -21.
AMA StyleXiao Hu, Jianzhong Lin, Dongmei Chen, Xiaoke Ku. Dynamics of self-organizing single-line particle trains in the channel flow of a power-law fluid. Chinese Journal of Chemical Engineering. 2020; 34 ():12-21.
Chicago/Turabian StyleXiao Hu; Jianzhong Lin; Dongmei Chen; Xiaoke Ku. 2020. "Dynamics of self-organizing single-line particle trains in the channel flow of a power-law fluid." Chinese Journal of Chemical Engineering 34, no. : 12-21.
The inertial migration of the elliptical and rectangular particles in a channel flow of a power-law fluid is studied using the lattice Boltzmann method. The numerical method and code are validated by comparing the present results with the previous ones. Effects of power-law index (n) of the fluid, particle shape, particle aspect ratio (α), blockage ratio (k) and Reynolds number (Re) on the particle trajectory and equilibrium position are discussed. The results show that the elliptical and rectangular particles will finally oscillate in a lateral equilibrium position. The distance for the particle from its initial position to the stable equilibrium position is the shortest for the rectangular particle, then followed for the elliptical particle and finally for the circular particle and square particle, the distance is the shortest for the shear-thinning fluid, then followed for the Newtonian fluid and finally for the shear-thickening fluid. This distance for the rectangular particle decreases with increasing Re, but the dependence of the distance on Re for the elliptical particle is not as obvious as that for the rectangular particle. The particle with larger aspect ratio and blockage ratio gets to the equilibrium position faster. The lateral distance from the equilibrium position to the channel centerline is reduced with increasing k, and with decreasing α for both elliptical and rectangular particles. For the particles with larger α, the lateral distance is reduced with the increase of Re, but the relationship between the lateral distance and Re for the particles with smaller α is dependent on n.
Xiao Hu; Jianzhong Lin; Yu Guo; Xiaoke Ku. Motion and equilibrium position of elliptical and rectangular particles in a channel flow of a power-law fluid. Powder Technology 2020, 377, 585 -596.
AMA StyleXiao Hu, Jianzhong Lin, Yu Guo, Xiaoke Ku. Motion and equilibrium position of elliptical and rectangular particles in a channel flow of a power-law fluid. Powder Technology. 2020; 377 ():585-596.
Chicago/Turabian StyleXiao Hu; Jianzhong Lin; Yu Guo; Xiaoke Ku. 2020. "Motion and equilibrium position of elliptical and rectangular particles in a channel flow of a power-law fluid." Powder Technology 377, no. : 585-596.
Particle migration and trajectory patterns in a confined simple shear-flow of Giesekus viscoelastic fluid are studied numerically using the direct forcing/fictitious domain method with Reynolds number, Re, from 0.1 to 50, Weissenberg number, Wi, from 0.1 to 1.0, and ratio of solvent viscosity to total viscosity at 0.3. The method is validated by comparing the present results with previous numerical results and experimental data. The effects of fluid inertia and elasticity, wall confinement, and initial horizontal distance between two particles on particle migration and trajectory pattern are analyzed. The results show that there exist two trajectory patterns, that is, “returning” and “passing” patterns. The separatrix between the two patterns and the velocity variation of particles are dependent on Re and h (initial vertical distance between the two particles). The elastic effect promotes a change in particle trajectory from the returning to the passing pattern when the elasticity number is large, while the inertial effect promotes a change in particle trajectory from the passing to the returning pattern. A large extension force causes the two particles to pass over each other. Wall confinement promotes a change in particle trajectory from the passing to the returning pattern. The initial horizontal distance, l, between two particles has no effect on the trajectory pattern when the inertial effect is small. The larger l is, the more likely it is that the returning pattern appears. The particle trajectories are closer to the centerline when l is large.
Bingrui Liu; Jianzhong Lin; Xiaoke Ku; Zhaosheng Yu. Elasto-inertial particle migration in a confined simple shear-flow of Giesekus viscoelastic fluids. Particulate Science and Technology 2020, 39, 726 -737.
AMA StyleBingrui Liu, Jianzhong Lin, Xiaoke Ku, Zhaosheng Yu. Elasto-inertial particle migration in a confined simple shear-flow of Giesekus viscoelastic fluids. Particulate Science and Technology. 2020; 39 (6):726-737.
Chicago/Turabian StyleBingrui Liu; Jianzhong Lin; Xiaoke Ku; Zhaosheng Yu. 2020. "Elasto-inertial particle migration in a confined simple shear-flow of Giesekus viscoelastic fluids." Particulate Science and Technology 39, no. 6: 726-737.
We simulated the sedimentations of two unequal spheres with different densities in a square tube for Galileo numbers (Ga) from 5 to 25, resulting in a Reynolds number range of $0.8\leqslant Re_{T}\leqslant 17.3$ based on the terminal settling velocity. The sedimentation of spheres with different densities is dynamically more complex than that of identical spheres. At high Ga the spheres oscillate in the centreline plane of the tube, where they are initially released from rest. By contrast, the spheres move to the diagonal or reverse–diagonal plane of the tube at low Ga, reaching a steady or periodic state depending on the density difference between them. A phase diagram illustrates the transitions between different sedimentation behaviours depending on Ga and the density difference. A possible mechanism for these behaviours is also presented. Furthermore, we compare two-dimensional (2-D) and three-dimensional computations for our system to attain a better understanding of the hydrodynamic interactions between two unequal spheres at low but finite Reynolds number. Comparing relative trajectories, periods of oscillation and flow features shows that 2-D circular cylinders oscillate much more strongly and frequently than spheres under the same flow conditions. In particular, spheres do not have the discontinuity in period that arises in the 2-D case from the change in rotation sign of a heavy particle.
Deming Nie; Jianzhong Lin. Simulation of sedimentation of two spheres with different densities in a square tube. Journal of Fluid Mechanics 2020, 896, 1 .
AMA StyleDeming Nie, Jianzhong Lin. Simulation of sedimentation of two spheres with different densities in a square tube. Journal of Fluid Mechanics. 2020; 896 ():1.
Chicago/Turabian StyleDeming Nie; Jianzhong Lin. 2020. "Simulation of sedimentation of two spheres with different densities in a square tube." Journal of Fluid Mechanics 896, no. : 1.
The inertial focusing of particles in channel flow of a Newtonian fluid is studied using the lattice Boltzmann method. The effects of Reynolds number (Re) and blockage ratio (k) on the stability condition of self-organizing staggered particle trains are explored. The results show that, for staggered particle pairs, the particles will move close to each other with a damped oscillatory trajectory and form a steady horizontal spacing eventually. For single-line particle pairs, the inter-particle spacing increases continuously to a larger value for further downstream. Two lines of 12 particles will self-organize the staggered particle trains. The formation of stable staggered particle trains is dependent on Re and k. Particles with low k in the staggered particle trains are more likely to be unstable or fluctuate within a certain range when Re is larger than a critical value. As k increases, the critical values of Re corresponding to the inter-particle spacing with a stable value or a certain range of fluctuation are also increased. The mean particle spacing decreases with increasing k and decreasing Re, and the blockage ratio k has a greater effect on the particle spacing than Reynolds number Re.
Xiao Hu; Jianzhong Lin; Dongmei Chen; Xiaoke Ku. Stability condition of self-organizing staggered particle trains in channel flow. Microfluidics and Nanofluidics 2020, 24, 1 -12.
AMA StyleXiao Hu, Jianzhong Lin, Dongmei Chen, Xiaoke Ku. Stability condition of self-organizing staggered particle trains in channel flow. Microfluidics and Nanofluidics. 2020; 24 (4):1-12.
Chicago/Turabian StyleXiao Hu; Jianzhong Lin; Dongmei Chen; Xiaoke Ku. 2020. "Stability condition of self-organizing staggered particle trains in channel flow." Microfluidics and Nanofluidics 24, no. 4: 1-12.
Flow resistance and bubble transport in a helical static mixer were studied experimentally and numerically. The inline mixer increases the volume fraction of gas in liquids by breaking bubbles into smaller sizes with a micrometer size in the flow experiments. The gas–liquid flow was simulated by a combination of computational fluid dynamics and Taylor expansion methods of moments. The friction factor of the helical static mixer is much smaller than that of the Kenics static mixers. The pressure drop increases with the Reynolds number, and the increment is larger when the Reynolds number is higher. The equidistant pressure drop increases with the argument of Reynolds number, and increases when the pitch decreases from upstream to downstream. The energy expenditure increases significantly when the variable-pitch coefficient is too small. The bubble geometric mean diameter decreases and the geometric standard deviation increases when the gas–liquid fluid flows through the mixer. The variable pitch structure enhances the bubble breakup effectively. The change of the bubble size decreases with the argument of the Reynolds number. The effect of the mixer has a limitation on breaking the bubbles.
Fangyang Yuan; Zhengwei Cui; Jianzhong Lin. Experimental and Numerical Study on Flow Resistance and Bubble Transport in a Helical Static Mixer. Energies 2020, 13, 1228 .
AMA StyleFangyang Yuan, Zhengwei Cui, Jianzhong Lin. Experimental and Numerical Study on Flow Resistance and Bubble Transport in a Helical Static Mixer. Energies. 2020; 13 (5):1228.
Chicago/Turabian StyleFangyang Yuan; Zhengwei Cui; Jianzhong Lin. 2020. "Experimental and Numerical Study on Flow Resistance and Bubble Transport in a Helical Static Mixer." Energies 13, no. 5: 1228.
In this paper, the migrations of two interacting particles in a three-dimensional bounded shear flow of Giesekus fluids are numerically investigated using the direct forcing/fictitious domain method for the Weissenberg number ranging from 0.1 to 1.0, the mobility parameter α which quantifies the shear-thinning effect ranging from 0.01 to 0.7, and the ratio of the solvent viscosity to the total viscosity being 0.1. The model is first validated by comparing the numerical results with the available data in the literature. The effects of the Weissenberg number, the shear-thinning effect, and the initial vertical distance between two particles on the particle migrations are explored. Some of the results are in agreement with the experimental ones. The results show that the pattern of particle migrations can be roughly classified into “returning” and “passing”. The variations of particle velocity and pressure field in the “returning” pattern are totally different from those in the “passing” pattern. The separatrix between “returning” and “passing” pattern is dependent on the initial vertical distance between two particles, the Weissenberg number and the shear-thinning effect. With other parameters fixed, the trajectories of particle change from the “returning” pattern to the “passing” pattern as the initial vertical distance between two particles and the Weissenberg number increase, but as the shear-thinning effect decreases.
Bingrui Liu; Jianzhong Lin; Xiaoke Ku; Zhaosheng Yu. Particle migration in bounded shear flow of Giesekus fluids. Journal of Non-Newtonian Fluid Mechanics 2020, 276, 104233 .
AMA StyleBingrui Liu, Jianzhong Lin, Xiaoke Ku, Zhaosheng Yu. Particle migration in bounded shear flow of Giesekus fluids. Journal of Non-Newtonian Fluid Mechanics. 2020; 276 ():104233.
Chicago/Turabian StyleBingrui Liu; Jianzhong Lin; Xiaoke Ku; Zhaosheng Yu. 2020. "Particle migration in bounded shear flow of Giesekus fluids." Journal of Non-Newtonian Fluid Mechanics 276, no. : 104233.
The lateral migration of a spherical particle in a sheared Giesekus fluid is numerically studied by the direct-forcing fictitious domain method. The model is first validated by comparing the simulation results with the available data in the literature. Effects of the viscosity ratio, shear thinning, Weissenberg number, and wall confinement on the particle migration are examined. Results show that the particle migrates toward the wall, irrespective of whether the fluid is shear thinning. The wall confinement, shear thinning, and high Weissenberg number could respectively facilitate the particle lateral migration. While the effect of viscosity ratio on the particle migration is not monotonic, a separatrix value is found which divides the viscosity ratio into two ranges. Moreover, effects of rheological properties on the particle angular velocity and its variation throughout the migration pathway are also explored, and the position where the angular velocity starts to decrease is affected by fluid rheological properties.
Bingrui Liu; Jianzhong Lin; Xiaoke Ku; Zhaosheng Yu. Migration of spherical particles in a confined shear flow of Giesekus fluid. Rheologica Acta 2019, 58, 639 -646.
AMA StyleBingrui Liu, Jianzhong Lin, Xiaoke Ku, Zhaosheng Yu. Migration of spherical particles in a confined shear flow of Giesekus fluid. Rheologica Acta. 2019; 58 (10):639-646.
Chicago/Turabian StyleBingrui Liu; Jianzhong Lin; Xiaoke Ku; Zhaosheng Yu. 2019. "Migration of spherical particles in a confined shear flow of Giesekus fluid." Rheologica Acta 58, no. 10: 639-646.
Jianzhong Lin; Mingzhou Yu; Martin Seipenbusch; Xiaoke Ku; Yu Feng. Nanofluidics and Nanofluids. Journal of Nanotechnology 2019, 2019, 1 -2.
AMA StyleJianzhong Lin, Mingzhou Yu, Martin Seipenbusch, Xiaoke Ku, Yu Feng. Nanofluidics and Nanofluids. Journal of Nanotechnology. 2019; 2019 ():1-2.
Chicago/Turabian StyleJianzhong Lin; Mingzhou Yu; Martin Seipenbusch; Xiaoke Ku; Yu Feng. 2019. "Nanofluidics and Nanofluids." Journal of Nanotechnology 2019, no. : 1-2.
In this paper, the flow of power-law fluid over a circular cylinder near a moving wall is simulated numerically using a finite volume method for different Reynolds numbers (Re = 1, 10, 40), gap ratios (G/D = 0.2–1.0), and power-law indices (n = 0.5–1.5). The effects of fluid inertia, wall proximity, and rheological property on the drag and lift coefficient, gap flow characteristics, and recirculation modes are studied. Possible mechanisms for the variation of the drag and lift coefficient and the change in recirculation mode are addressed. The results show that the decrease in G/D or Re results in the increase in drag and lift coefficient, while the effect of n is dependent on Re and G/D. For the drag coefficient, shear-thickening fluid is more sensitive to the change of G/D. The variation of the lift coefficient can be explained by the movement of angular position of the front stagnation point. The redistribution of the flow around the cylinder results in different recirculation modes. Five distinct modes are found and the critical value of G/D for the mode change decreases with the decrease in n and increase in Re. Variation of the relative vortex intensity and the relative flow intensity nearby leads to the change of recirculation mode.
P. J. Zhang; J. Z. Lin; X. K. Ku. Flow of power-law fluid past a circular cylinder in the vicinity of a moving wall. Journal of the Brazilian Society of Mechanical Sciences and Engineering 2019, 41, 39 .
AMA StyleP. J. Zhang, J. Z. Lin, X. K. Ku. Flow of power-law fluid past a circular cylinder in the vicinity of a moving wall. Journal of the Brazilian Society of Mechanical Sciences and Engineering. 2019; 41 (1):39.
Chicago/Turabian StyleP. J. Zhang; J. Z. Lin; X. K. Ku. 2019. "Flow of power-law fluid past a circular cylinder in the vicinity of a moving wall." Journal of the Brazilian Society of Mechanical Sciences and Engineering 41, no. 1: 39.
Hydrodynamic interaction between swimmers in power-law fluid is systematically investigated by using an immersed boundary-lattice Boltzmann method. The squirmer model is applied to mimic swimmers and distinct kinematic features are found for them in different types of power-law fluids. For parallel interactions, pushers (a type of swimmers) attract each other to certain orientation angles eventually while pullers (another type of swimmers) push themselves away and turn to the head-to-head state. For interactions with initial swimming towards each other, puller eventually departs away from the other one while pusher is more easily locked at certain location. The feature of power-law fluid is responsible for the trajectories of locomotion. In addition, the distribution of viscosity around the swimmer deeply relies on the tangential velocity at the boundary. The peaks and valleys of the viscosity locate at sites where the streamlines are parallel and normal to the surface of the swimmer, respectively. Finally, the collision time for neutral swimmer (β=0) and a kind of puller (β=2.5) decreases as power-law index increases while a non-monotonic relation is found for another kind of puller (β=5).
Zhenyu Ouyang; Jianzhong Lin; Xiaoke Ku. Hydrodynamic interaction between a pair of swimmers in power-law fluid. International Journal of Non-Linear Mechanics 2018, 108, 72 -80.
AMA StyleZhenyu Ouyang, Jianzhong Lin, Xiaoke Ku. Hydrodynamic interaction between a pair of swimmers in power-law fluid. International Journal of Non-Linear Mechanics. 2018; 108 ():72-80.
Chicago/Turabian StyleZhenyu Ouyang; Jianzhong Lin; Xiaoke Ku. 2018. "Hydrodynamic interaction between a pair of swimmers in power-law fluid." International Journal of Non-Linear Mechanics 108, no. : 72-80.
The Poiseuille flow of power-law fluid over a free rotating cylinder eccentrically situated in a two-dimensional channel is numerically investigated via a BGK lattice Boltzmann method. Effects of power-law index, eccentricity ratio and Reynolds number on flow patterns and rotational behavior of the pinned cylinder are systematically explored within wide ranges of Reynolds numbers (1 ≤ Re ≤ 100), eccentricity ratios (0 ≤ λ ≤ 11/12) and power-law indexes (0.6 ≤ n ≤ 1.4). Results show that the ‘anomalous’ rotation (clockwise rotation) of the pinned cylinder is mainly induced by flow inertia. The mean rotating velocity generally decreases with an increase in Reynolds number except in low Reynolds number region and it also increases with power-law index because viscosity progressively becomes essential. Such effect of power-law index on the mean rotating velocity is greater at moderate local Reynolds number and intermediate eccentricity ratio. A physical argument is created to characterize the combined effect of Reynolds number and power-law index. In the vicinity of channel wall or near the centerline, the pinned cylinder tends to rotate in a normal way. The ‘anomalous’ rotation is inclined to appear at intermediate eccentricity ratio. Moreover, the critical Reynolds numbers beyond which the pinned cylinder changes the rotating direction are evaluated at various combinations of eccentricity ratio and power-law index. In addition, the instantaneous rotating velocity of the pinned cylinder is more stable at a lower Reynolds number, higher power-law index, considerably higher eccentricity ratio or quite near the channel centerline.
Yi Xia; Jianzhong Lin; Xiaoke Ku. Flow-induced rotation of circular cylinder in Poiseuille flow of power-law fluids. Journal of Non-Newtonian Fluid Mechanics 2018, 260, 120 -132.
AMA StyleYi Xia, Jianzhong Lin, Xiaoke Ku. Flow-induced rotation of circular cylinder in Poiseuille flow of power-law fluids. Journal of Non-Newtonian Fluid Mechanics. 2018; 260 ():120-132.
Chicago/Turabian StyleYi Xia; Jianzhong Lin; Xiaoke Ku. 2018. "Flow-induced rotation of circular cylinder in Poiseuille flow of power-law fluids." Journal of Non-Newtonian Fluid Mechanics 260, no. : 120-132.
A coupled numerical model for nanorod-based suspension flow is constructed, and the convective heat transfer and resistance characteristics of the nanofluid duct flow are investigated. The numerical results are verified by experimental results and theoretical models. Most of nanorods are located randomly in the bulk fluid, while particles near the wall aligned with the flow direction. Friction factor of nanofluids with nanorods increases with higher particle volume concentration or aspect ratio, but the increment reduces when the Reynolds number gets larger. The relative Nusselt number is obtained to characterize the intensity of convective heat transfer. The results show that the Nusselt number of nanofluids increases when the particle volume concentration or aspect ratio becomes larger. Compared to increasing the aspect ratio of nanorods, increasing the particle volume concentration would be more effective on enhancing the convective heat transfer intensity in industrial applications although it will cause a slight increase of resistance.
Fangyang Yuan; Jianzhong Lin; Jianfeng Yu. Numerical Research on Convective Heat Transfer and Resistance Characteristics of Turbulent Duct Flow Containing Nanorod-Based Nanofluids. Journal of Nanotechnology 2018, 2018, 1 -9.
AMA StyleFangyang Yuan, Jianzhong Lin, Jianfeng Yu. Numerical Research on Convective Heat Transfer and Resistance Characteristics of Turbulent Duct Flow Containing Nanorod-Based Nanofluids. Journal of Nanotechnology. 2018; 2018 ():1-9.
Chicago/Turabian StyleFangyang Yuan; Jianzhong Lin; Jianfeng Yu. 2018. "Numerical Research on Convective Heat Transfer and Resistance Characteristics of Turbulent Duct Flow Containing Nanorod-Based Nanofluids." Journal of Nanotechnology 2018, no. : 1-9.