广义混合流体中纤毛通过电渗透区的流动模拟

本文建立了一个广义纳米流体流动模型,研究磁流体中纤毛毯在通过电渗透通道时对其运输的作用,并对混合纳米流体的特性进行解释。通过假设长波长和低雷诺数估计,将流体的流动分析方程转换为无量纲形式;用数学解法得到速度分布、压力梯度和流函数的解析解;用图表表明相关物理参数的影响。该模型具有重要的应用价值,可应用于生物运输过程、人工纤毛设计和其他机械装置的操作等领域。

Simulation of Variable Viscosity and Jeffrey Fluid Model for Blood Flow Through a Tapered Artery with a Stenosis

Non-Newtonian fluid model for blood flow through a tapered artery with a stenosis and variable viscosity by modeling blood as Jeffrey fluid has been studied in this paper.The Jeffrey fluid has two parameters,the relaxation time λ1 and retardation time λ2.The governing equations are simplified using the case of mild stenosis.Perturbation method is used to solve the resulting equations.The effects of non-Newtonian nature of blood on velocity profile,temperature profile,wall shear stress,shearing stress at the stenotsis throat and impedance of the artery are discussed.The results for Newtonian fluid are obtained as special case from this model.

反相高效液相色谱法测定有机氯及含氮杀虫剂在水体·土壤沉积物及鱼体中的残留(摘要)(英文)

[目的]测定水体、土壤沉积物以及鱼体内有机氯及含氮杀虫剂残留物,为科学评估杀虫剂残留对巴基斯坦地区公共卫生、农业和环境的影响提供依据。[方法]以食用鱼南亚野鲮为材料,设计2组体重,采用高效液相色谱法分别测定水体、土壤沉积物以及南亚野鲮体内α-硫丹、DDE、甲基对硫磷、异丙隆、呋喃丹、阿特拉津等含量。[结果]土壤沉积物中DDE的含量达(2.340±0.025)μg/g,在250 ～750 g的南亚野鲮体内的含量分别为(0.270 ±0.000 6)μg/g,但在水体中未发现DDE残留;不同饲料中农药残留物90%为有机磷、呋喃丹以及有机氯杀虫剂,6%为杀菌剂,仅4%为除草剂,在250 ～750 g以及800 ～1 300 g的南亚野鲮体内硫丹的含量分别达到(0.491±0.000 6)μg/g和(3.050±0.060 8)μg/g,异丙隆的含量分别达到(0.010±0.0003)μg/g和(0.014±0.000 6)μg/g,且随体重上升,其脂肪含量增加,积累的农药残留物则越多;硫丹、甲基对硫磷、阿特拉津和呋喃丹的含量在水体达到最大残留限量水平0.001μg/g。[结论]通过生物积累和在自然界中的运输以及再沉积作用,有机氯及其他杀虫剂的使用给全球的环境造成了严重污染,因此,在巴基斯坦已经禁止使用DDT等有机氯农药。

Endoscopic Effects on Peristaltic Flow of a Nanofluid

在现在的调查，我们在内诊镜学习了 nanofluid 的蠕动的流动。流动在与波浪 c 的速度移动的一个波浪原则被调查。当准确答案为速度和压力坡度被计算了时，分析答案为温度和 nanoparticle 方程用 Homotopy 不安方法(HPM ) 被计算了。数字集成被用来为压力上升和摩擦力量获得图形的结果。各种各样的出现参数的效果为五个不同蠕动的波浪被调查。优化在文章的结束被阴谋。

Heat transfer analysis of Williamson fluid over exponentially stretching surface

This study explores the effects of heat transfer on the Williamson fluid over a porous exponentially stretching surface. The boundary layer equations of the Williamson fluid model for two dimensional flow with heat transfer are presented. Two cases of heat transfer are considered, i.e., the prescribed exponential order surface temperature （PEST） case and the prescribed exponential order heat flux （PEHF） case. The highly nonlinear partial differential equations are simplified with suitable similar and non-similar variables, and finally are solved analytically with the help of the optimal homotopy analysis method （OHAM）. The optimal convergence control parameters are obtained, and the physical fea- tures of the flow parameters are analyzed through graphs and tables. The skin friction and wall temperature gradient are calculated.

Dual solutions in MHD stagnation-point flow of Prandtl fluid impinging on shrinking sheet

The present article investigates the dual nature of the solution of the magneto- hydrodynamic （MHD） stagnation-point flow of a Prandtl fluid model towards a shrinking surface. The self-similar nonlinear ordinary differential equations are solved numerically by the shooting： method. It is found that the dual solutions of the flow exist for cer- tain values of tile velocity ratio parameter. The special case of the first branch solutions （the classical Newtonian fluid model） is compared with the present numerical results of stretching flow. The results are found to be in good agreement. It is also shown that the boundary layer thickness for the second solution is thicker than that for the first solution.

Partial slip effect on non-aligned stagnation point nanofluid over a stretching convective surface

The present study inspects the non-aligned stagnation point nano fluid over a convective surface in the presence of partial slip. Two types of base fluids namely water and kerosene are selected with Cu nanoparticles. The governing physical problem is presented and transformed into a system of coupled nonlinear differential equations using suitable similarity transformations. These equations are then solved numerically using midpoint integration scheme along with Richardson extrapolation via Maple. Impact of relevant physical parameters on the dimensionless velocity and temperature profiles are portrayed through graphs. Physical quantities such as local skin frictions co-efficient and Nusselt numbers are tabularized.It is detected from numerical computations that kerosene-based nano fluids have better heat transfer capability compared with water-based nanofluids. Moreover it is found that water-based nanofluids offer less resistance in terms of skin friction than kerosene-based fluid. In order to authenticate our present study, the calculated results are compared with the prevailing literature and a considerable agreement is perceived for the limiting case.

MHD stagnation point flow towards heated shrinking surface subjected to heat generation/absorption

The magnetohydrodynamic （MHD） stagnation point flow of micropolar flu- ids towards a heated shrinking surface is analyzed. The effects of viscous dissipation and internal heat generation/absorption are taken into account. Two explicit cases, i.e., the prescribed surface temperature （PST） and the prescribed heat flux （PHF）, are discussed. The boundary layer flow and energy equations are solved by employing the homotopy analysis method. The quantities of physical interest are examined through the presenta- tion of plots/tabulated values. It is noticed that the existence of the solutions for high shrinking parameters is associated closely with the applied magnetic field.

Heat transfer and Helmholtz-Smoluchowski velocity in Bingham fluid flow

A mathematical study is developed for the electro-osmotic flow of a nonNewtonian fluid in a wavy microchannel in which a Bingham viscoplastic fluid model is considered.For electric potential distributions,a Poisson-Boltzmann equation is employed in the presence of an electrical double layer(EDL).The analytical solutions of dimensionless boundary value problems are obtained with the Debye-Huckel theory,the lubrication theory,and the long wavelength approximations.The effects of the Debyelength parameter,the plug flow width,the Helmholtz-Smoluchowski velocity,and the Joule heating on the normalized temperature,the velocity,the pressure gradient,the volumetric flow rate,and the Nusselt number for heat transfer are evaluated in detail using graphs.The analysis provides important findings regarding heat transfer in electroosmotic flows through a wavy microchannel.

Effects of induced magnetic field on peristaltic flow of Johnson-Segalman fluid in a vertical symmetric channel

In this paper, the influence of heat transfer and induced magnetic field on peristaltic flow of a Johnson-Segalman fluid is studied. The purpose of the present investigation is to study the effects of induced magnetic field on the peristaltic flow of non-Newtonian fluid. The two-dimensional equations of a Johnson-Segalman fluid are simplified by assuming a long wavelength and a low Reynolds number. The obtained equations are solved for the stream function, magnetic force function, and axial pressure gradient by using a regular perturbation method. The expressions for the pressure rise, temperature, induced magnetic field, pressure gradient, and stream function are sketched and interpreted for various embedded parameters.

Mixed Convection Heat Transfer in Micropolar Nanofluid over a Vertical Slender Cylinder

Analysis is carried for the problem of boundary layer steady flow and heat transfer of a micropolar fluid containing nanoparticles over a vertical cylinder.The governing partial differential equations of linear momentum,angular momentum,heat transfer and nano concentration are reduced to nonlinear coupled ordinary differential equations by applying the boundary layer approximations and a suitable similarity transformation.These nonlinear coupled ordinary differential equations,subject to the appropriate boundary conditions,are then solved by using the homotopy analysis method.The effects of the physical parameters on the flow,heat transfer and nanoparticle concentration characteristics of the model are presented through graphs and the salient features are discussed.

Peristaltic flow of a heated Jeffrey fluid inside an elliptic duct:streamline analysis

The peristaltic flow of a heated Jeffrey fluid inside a duct with an elliptic cross-section is studied.A thorough heat transfer mechanism is interpreted by analyzing the viscous effects in the energy equation.The governing mathematical equations give dimensionless partial differential equations after simplification.The final simplified form of the mathematical equations is evaluated with respect to the relevant boundary conditions,and the exact solution is attained.The results are further illustrated by graphs,and the distinct aspects of peristaltic flow phenomena are discussed.

Peristaltic flow of Walter’s B fluid in endoscope

The peristaltic flow of a Walter＇s B fluid in an endoscope is studied. The problem is modeled in a cylindrical coordinate system. The main theme of the present analysis is to study the endoscopic effects on the peristaltic flow of the Waiter＇s B fluid. To the best of the authors＇ knowledge, no investigation has been made so far in the literatures to study the Walter＇s B fluid in an endoscope. Analytical solutions axe obtained using the regular perturbation method by taking 5 as a perturbation parameter. The approximate analytical solutions for the pressure rise and friction forces are evaluated using numerical integration. The effects of emerging parameters of the Waiter＇s B fluid are presented graphically.

Boundary Layer Flow over a Curved Surface Imbedded in Porous Medium

This research is made to visualize the boundary layer flow by a curved stretching sheet embedded in porous medium. The geometry is bended(curved), therefore the curvilinear coordinates are used to model the present problem.Fluid is electrically conducting with the presence of uniform magnetic field. The governing non-linear partial differential equation reduces to non-linear ordinary differential equations by using the dimensionless suitable transformations. The numerical solutions are obtained by using the method bvp4c from MATLAB. The effects of curvature parameter, nondimensional magnetic parameter, and porosity parameter on the velocity field and skin friction coefficient are examined.The skin friction profile enhances with enhancing the values of porosity and magnetic parameter. Comparison of the present results with the existing results in the literature for the flat surface is also given.

The Mathematical Analysis for Peristaltic Flow of Hyperbolic Tangent Fluid in a Curved Channel

In the present paper, we have investigated the peristaltic flow of hyperbolic tangent fluid in a curved channel. The governing equations of hyperbolic tangent fluid model for curved channel are derived including the effects of curvature. The highly nonlinear partial differential equations are simplified by using the wave frame transformation,long wave length and low Reynolds number assumptions. The reduced nonlinear partial differential equation is solved analytically with the help of homotopy perturbation method (HPM). The physical features of pertinent parameters have been discussed by plotting the graphs of pressure rise and stream functions.

Role of Inclined Magnetic Field and Copper Nanoparticles on Peristaltic Flow of Nanofluid through Inclined Annulus: Application of the Clot Model

A genuine neurotic condition is experienced when some blood constituents accumulate on the wall of the artery get withdrew from the wall, again join the circulatory system and coagulation occur. Role of copper nanoparticles and inclined magnetic field on the peristaltic flow of a nanofluid in an annular region of inclined annulus is investigated.We represent the clot model by considering the small artery as an annulus whose outer tube has a wave of sinusoidal nature and inner tube has a clot on its walls. Lubrication approach is used to simplify the problem. Close form solutions are determined for temperature and velocity profile. Impact of related parameters on pressure rise, pressure gradient,velocity and streamlines are interpreted graphically. Comparison among the pure blood and copper blood is presented and analyzed. One main finding of the considered analysis is that the inclusion of copper nanoparticles enlarges the amplitude of the velocity. Therefore, the considered study plays a dominant role in biomedical applications.

Physiological Flow of Jeffrey Six Constant Fluid Model due to Ciliary Motion

The main purpose of this article is to present a mathematical model of ciliary motion in an annulus. In this analysis, the peristaltic motion of non-Newtonian Jeffrey six constant fluid is observed in an annulus with ciliated tips in the presence of heat and mass transfer. The effects of viscous dissipation are also considered. The flow equations of non-Newtonian fluid for the two-dimensional tube in cylindrical coordinates are simplified using the low Reynolds number and long wave-length approximations. The main equations for Jeffrey six constant fluid are considered in cylindrical coordinates system. The resulting nonlinear problem is solved using the regular perturbation technique in terms of a variant of small dimensionless parameter α. The results of the solutions for velocity, temperature and concentration field are presented graphically. B_k is Brinkman number, ST is soret number, and SH is the Schmidth number. Outcome for the longitudinal velocity, pressure rise, pressure gradient and stream lines are represented through graphs. In the history, the viscous-dissipation effect is usually represented by the Brinkman number.

Mathematical Analysis for Peristaltic Flow of Two Phase Nanofluid in a Curved Channel

This paper describes the theoretical analysis for peristaltic motion of water base nanoBuid containing distinct types of the nanoparticles like Cu,TiO_2,and Al_2O_3.Equations of nano Quid are modelled and simplified by constructing the suppositions of low Reynolds number as well as long wave length.The reduced equations are solved exactly.Solutions are represented through graphs.Outcomes for the velocity,temperature,pressure rise and stream lines are analyzed graphically.The work presented here is based on the fictitious values,however some other values can be tested experimentally.

Radiation efects on MHD stagnation point flow of nano fluid towards a stretching surface with convective boundary condition

The aim of the present paper is to study the numerical solutions of the steady MHD two dimensional stagnation point flow of an incompressible nano fluid towards a stretching cylinder.The effects of radiation and convective boundary condition are also taken into account.The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis.The resulting nonlinear momentum,energy and nano particle equations are simplifed using similarity transformations.Numerical solutions have been obtained for the velocity,temperature and nanoparticle fraction profles.The influence of physical parameters on the velocity,temperature,nanoparticle fraction,rates of heat transfer and nanoparticle fraction are shown graphically.

A Clot Model Examination: with Impulsion of Nanoparticles under Influence of Variable Viscosity and Slip Effects

In this speculative analysis, our main focused is to address the neurotic condition that occurs due to accumulation of blood components on the wall of the artery that results in blood coagulation. Specifically, to perceive this phenomena clot model is considered. To discuss this analysis mathematical model is formed in the presence of the effective thermal conductivity and variable viscosity of base fluid. Appropriate slip conditions are employed to obtain the close form solutions of temperature and velocity profile. The graphical illustrations have been presented for the assessment of pressure rise, pressure gradient and velocity profile. The effects of several parameters on the flow quantities for theoretical observation are investigated. At the end, the results confirmed that the impulsion of copper and silver nanoparticles as drug agent enlarges the amplitude of the velocity and hence nanoparticles play an important role in engineering and biomedical applications such as drug delivery system.