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1.
This paper deals with the motion of viscous liquid column with finite length and two free surfaces in a vertical straight capillary tube. It is assumed that fluid is Newtonian. Linearizing the boundary conditions, analytic expressions in the form of infinite series have been obtained for velocity, piessure and free surface at low Reynolds number. The numerical calculation is carried out for a set of cylinder’s length of water and blood. It has been revealed that there are considerable circulating currents at the upper and lower meniscuses. Its maximum velocity is about 57% of the average velocity of the mainstream. Iner-tial effect is also studied in this paper. Using the time-dependent method in finite difference techniques, numerical solution of the corresponding nonlinear equation at Re<24.5 is computed. Comparing it with analytic exact solution at low Reynolds number shows that inertial effect is negligible provided Re<24.5. 相似文献
2.
Nanotwinned polycrystals exhibit an excellent strength-ductility combination due to nanoscale twins and grains. However, nanotwin-assisted grain coarsening under mechanical loading reported in recent experiments may result in strength drop based on the Hall-Petch law. In this paper, a phase-field model is developed to investigate the effect of coupled evolutions of twin and grain boundaries on nanotwin-assisted grain growth. The simulation result demonstrates that there are three pathways for coupled motions of twin and grain boundaries in a bicrystal under the applied loading, dependent on the amplitude of applied loading and misorientation of the bicrystal. It reveals that a large misorientation angle and a large applied stress promote the twinning-driven grain boundary migration. The resultant twin-assisted grain coarsening is confirmed in the simulations for the microstructural evolutions in twinned and un-twinned polycrystals under a high applied stress. 相似文献
3.
I. M. Starobin 《Fluid Dynamics》1981,16(2):301-304
A study is made of the closed flow of a viscous incompressible Newtonian liquid in a deformed tube with a section used as a peristaltic pump connected to a given hydraulic load. The time-average flow rate of the liquid (blood) in the external section is determined, together with the pressure difference across the load and the condition for the absence of hemolysis.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 177–179, March–April, 1981. 相似文献
4.
The present theoretical assessment deals with the peristaltic-ciliary transport of a developing embryo within a fallopian tubal fluid in the human fallopian tube. A mathematical model of peristalsis-cilia induced flow of a linearly viscous fluid within a fallopian tubal fluid in a finite two-dimensional narrow tube is developed. The lubrication approximation theory is used to solve the resulting partial differential equation. The expressions for axial and radial velocities, pressure gradient, stream function, volume flow rate, and time mean volume flow rate are derived. Numerical integration is performed for the appropriate residue time over the wavelength and the pressure difference over the wavelength. Moreover, the plots of axial velocity, the appropriate residue time over wavelength, the vector, the pressure difference over wavelength, and the streamlines are displayed and discussed for emerging parameters and constants. Salient features of the pumping characteristics and the trapping phenomenon are discussed in detail. Furthermore, a comparison between the peristaltic flow and the peristaltic-ciliary flow is made as the special case. Relevance of the current results to the transport of a developing embryo within a fallopian tubal fluid from ampulla to the intramural in the fallopian tube is also explored. It reveals the fact that cilia along with peristalsis helps to complete the required mitotic divisions while transporting the developing embryo within a fallopian tubal fluid in the human fallopian tube. 相似文献
5.
A. E. Medvedev 《Journal of Applied Mechanics and Technical Physics》2009,50(4):566-569
An approximate solution of the problem of unsteady motion of a viscous incompressible fluid in a long narrow deformable tube
at low Reynolds numbers is obtained. Pressure oscillations and tube deformation are shown to be related by an integrodifferential
equation. The solution obtained extends the Poiseuille solution in elliptic tubes to the case of comparatively arbitrary small
deformations in terms of the tube length and angle.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 4, pp. 28–32, July–August, 2009. 相似文献
6.
I.IntroductionThefunctionofanaPbliedmagneticfield\onhumanbodieshasbeenknownandservedasakindofthemedicaltreatmentforalongtime.ThemagneticstoneusedasamedicineisrdeordedinShennongMaterlbMedica,'which.isthefirstChinesemedicinebookandwaswrittenin200A.D..ItwasalsorecordedtyancientGreecethatholdingmagneticstQnesinhandsandfeetcouldrelievethepainandspasml'l.However,beinglimitedbythelevelQfproductionandmedicaltreatmentsatthattime,themagnetictreatmentwasmainlyusedforlocallydephlogisticating,relievin… 相似文献
7.
酆庆增 《应用数学和力学(英文版)》1997,18(9):865-870
I.Introducti0nCosmicmagneticfieldswhichoccurinregionsofhighelectricalconductivityandlowdensitymightoftensatisfytheforce-freeconditioncurlH=a(r,t)H(l.l)whereHdenotesthedensityofthemagneticfleld,and2issomescalarfunctionofpositionandtime,sincethepressuregrad… 相似文献
8.
ProjcctsupportedbytheNatiol1alNaturalScienceFoundatio11ofChinaThemagnatictherapy,asaneffccti\'emedicaltreatment,hasabroadapp1icatiQn.lnrecentyears,plentyofanimalandclinicalresearcheshavebeendoneandprovedthatmagneticfieldhassuchpositivecurativeefttctsasant… 相似文献
9.
O. Yu. Tsvelodub 《Journal of Applied Mechanics and Technical Physics》2008,49(2):231-238
A thin film flow of a viscous liquid flowing down a vertical wall in the field of the gravity force is studied. The values
of temperatures on the solid wall and on the free surface are constant. The viscosity and thermal diffusivity are functions
of temperature. An equation that describes the evolution of surface disturbances is derived for small flow rates in the long-wave
approximation.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 2, pp. 89–97, March–April, 2008. 相似文献
10.
A two-dimensional nonisothermal model of magma flow in a volcanic conduit is proposed. The model makes it possible to investigate the effect of the processes of viscous dissipation and heat conduction on the magma flow. It is established that the effect of these processes is significant, particularly in the case of high flow rates. It is shown that in this case the conduit resistance calculated from the Poiseuille formula widely used in one-dimensional models is highly overestimated. This is related to the formation of a strongly heated fluid layer with reduced viscosity in the near-wall conduit zone. Within the framework of the proposed model it is possible to describe eruptions with flow rates which are several times higher than the flow rates obtained within the framework of one-dimensional models.Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 6, 2004, pp. 21–32. Original Russian Text Copyright © 2004 by Barmin, Vedeneeva, and Melnik. 相似文献
11.
The laminar and parallel flow of a Newtonian fluid in a vertical cylindrical duct with circular cross section has been analysed.
Both the viscous dissipation effect and the buoyancy effect have been taken into account. The momentum balance equation and
the energy balance equation have been solved by means of a perturbation method, in the case of a uniform heat flux prescribed
at the wall of the duct. The velocity distribution, the temperature distribution, the Nusselt number and the Fanning friction
factor have been evaluated analytically. Moreover, the velocity and temperature of the fluid have been compared with those
obtained in two special cases: forced convection with viscous dissipation (i.e. negligible buoyancy effect); mixed convection
with negligible effects of viscous dissipation.
Received on 26 June 2000 相似文献
12.
13.
M. Sedl 《国际流体数值方法杂志》1993,16(11):953-966
This paper discusses the calculation of quasi-three-dimensional incompressible viscous flow by FEM. The Reynolds-averaged Navier-Stokes equations are solved in curvilinear co-ordinates by the reduced integration and penalty method (RIP). Streamline upwind artificial viscosity (SUAV) and the Baldwin-Lomax algebraic model of turbulence are used. Time discretization is by the general implicit θ-method. 相似文献
14.
A process has been developed recently to fabricate a structure comprising, from top to bottom, a SiGe thin film, a glass layer,
and a Si wafer. The SiGe film is a perfect crystal, and is under biaxial compression. The SiGe film is patterned into islands.
On annealing, the glass flows and the islands relax. The resulting strain-free islands are used as substrates, to grow epitaxial
optoelectronic devices. This article describes a series of studies on the annealing process, combining experiment and theory.
A small island relaxes by expansion, starting at the edges and diffusing to the center. A large island wrinkles before the
expansion reaches the center. After some time, the wrinkles either disappear, or cause the island to fracture. We model the
island as an elastic plate, and the glass layer as a viscous liquid. The strains in the islands are measured by X-ray diffraction
and Raman spectroscopy, and the wrinkle amplitudes by atomic force microscope. The data are compared with the theoretical
predictions. We determine the conditions under which the islands relax by expansion without significant wrinking, and demonstrate
that a cap layer suppresses wrinkles, relaxing a large island crack-free.
The project supported by NSF (CMS-9820713), DARPA (N66001-00-1-8957), ARO (DAA655-98-1-0270), and New Jersey Science and Technology
Commission 相似文献
15.
16.
P. K. Volkov 《Journal of Applied Mechanics and Technical Physics》1989,30(6):928-936
Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, Vol. 30, No. 6, pp. 98–105, November–December, 1989. 相似文献
17.
Kamel Hooman Alireza Pourshaghaghy Arash Ejlali 《应用数学和力学(英文版)》2006,27(5):617-626
The viscous dissipation effect on forced convection in a porous saturated circular tube with an isoflux wall is investigated on the basis of the Brinkman flow model. For the thermally developing region, a numerical study is reported while a perturbation analysis is presented to find expressions for the temperature profile and the Nusselt number for the fully developed region. The fully developed Nusselt number found by numerical solution for the developing region is compared with that of asymptotic analysis and a good degree of agreement is observed. 相似文献
18.
V. N. Vetlutskii V. L. Ganimedov M. I. Muchnaya 《Journal of Applied Mechanics and Technical Physics》2005,46(6):824-834
A two-phase flow with high Reynolds numbers in the subsonic, transonic, and supersonic parts of the nozzle is considered within
the framework of the Prandtl model, i.e., the flow is divided into an inviscid core and a thin boundary layer. Mutual influence
of the gas and solid particles is taken into account. The Euler equations are solved for the gas in the flow core, and the
boundary-layer equations are used in the near-wall region. The particle motion in the inviscid region is described by the
Lagrangian approach, and trajectories and temperatures of particle packets are tracked. The behavior of particles in the boundary
layer is described by the Euler equations for volume-averaged parameters of particles. The computed particle-velocity distributions
are compared with experiments in a plane nozzle. It is noted that particles inserted in the subsonic part of the nozzle are
focused at the nozzle centerline, which leads to substantial flow deceleration in the supersonic part of the nozzle. The effect
of various boundary conditions for the flow of particles in the inviscid region is considered. For an axisymmetric nozzle,
the influence of the contour of the subsonic part of the nozzle, the loading ratio, and the particle diameter on the particle-flow
parameters in the inviscid region and in the boundary layer is studied.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 6, pp. 65–77, November–December, 2005. 相似文献
19.
The transport of mass through a rectangular channel and of energy between parallel surfaces of polyatomic gases in the Knudsen regime and in the presence of external magnetic fields is calculated by means of a Monte Carlo algorithm. A four-parameter mathematical model is proposed that takes into account the dynamical aspects of molecule-surface interactions and the influence of external magnetic fields on the angular momentum of polyatomic molecules. The Monte Carlo algorithm makes use of the Latin super-cube sampling method, correlated samplings, and the concept of importance sampling. The four parameters are determined by an optimised method based on the Monte Carlo algorithm and on experimental results for the mass flux rate of the gases N2 and CO in the presence of external magnetic fields through a rectangular channel with surfaces coated with Au. The optimised values of the parameters are used to determine the behaviour of the mass flux rate through a rectangular channel and the heat flux between two parallel plates for the gases N2 and CO as a function of the applied magnetic field. The calculated curves fit the experimental data well.Received: 18 February 2003, Accepted: 2 September 2003, Published online: 12 December 2003PACS:
05.60.-k, 51.60. + aCorrespondence to: G.M. Kremer 相似文献