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1.
《应用数学和力学(英文版)》2017,(2)
This paper studies stratified magnetohydrodynamic(MHD) flow of tangent hyperbolic nanofluid past an inclined exponentially stretching surface. The flow is subjected to velocity, thermal, and solutal boundary conditions. The partial differential systems are reduced to ordinary differential systems using appropriate transformations.The reduced systems are solved for convergent series solutions. The velocity, temperature,and concentration fields are discussed for different physical parameters. The results indicate that the temperature and the thermal boundary layer thickness increase noticeably for large values of Brownian motion and thermophoresis effects. It is also observed that the buoyancy parameter strengthens the velocity field, showing a decreasing behavior of temperature and nanoparticle volume fraction profiles. 相似文献
2.
R. J. Gribben 《Applied Scientific Research》1967,17(4-5):270-290
Summary Steady, axisymmetric, magnetohydrodynamic flow with a stagnation point on an infinite plane wall is considered with a magnetic field applied normal to the wall. Solutions are obtained in the form of series for the velocity, magnetic field and temperature when the magnetic field parameter () and the ratio of viscosity to magnetic diffusivity () are small. The case=O(1) is considered briefly when solutions which Meyer3) obtained by physical order-of-magnitude arguments are derived mathematically as expansions in. Some remarks are made on the consistency of extending the results to flow within the boundary layer near the nose of a bluff body. 相似文献
3.
An analysis is carried out to study the momentum, mass and heat transfer characteristics on the flow of visco-elastic fluid (Walter's liquid-B model) past a stretching sheet in the presence of a transverse magnetic field.In heat transfer, two cases are considered:
- 1.
- The sheet with prescribed surface temperature (PST case); and
- 2.
- The sheet with prescribed wall heat flux (PHF case).
4.
In the present analysis, the influence of heat and mass transfer on the peristaltic flow of a hyperbolic tangent fluid in an asymmetric channel has been discussed. The highly nonlinear equations are simplified under lubrication approach. The perturbation and numerical solutions of the problem are not only discussed but the validity of the results is also being checked. The graphical results of the problem under discussion are also being brought under consideration to see the behavior of various physical parameters. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
5.
In the present paper we discuss the magnetohydrodynamic (MHD) peristaltic flow of a hyperbolic tangent fluid model in a vertical asymmetric channel under a zero Reynolds number and long wavelength approximation. Exact solution of the temperature equation in the absence of dissipation term has been computed and the analytical ex- pression for stream function and axial pressure gradient are established. The flow is analyzed in a wave frame of reference moving with the velocity of wave. The expression for pressure rise has been computed numerically. The physical features of pertinent parameters are analyzed by plotting graphs and discussed in detail. 相似文献
6.
The boundary-layer equations for axisymmetric stagnation point flow of a power-law fluid are solved by a similarity transformation, and values of the wall shear rate are obtained. Theoretical expressions for local and average Sherwood numbers are derived from the convective diffusion equation for systems with high Schmidt numbers. The results can be used to predict diffusion coefficients of dilute species in fluids with specified power-law characteristics. 相似文献
7.
Time-dependent, two-dimensional(2 D) magnetohydrodynamic(MHD)micropolar nanomaterial flow over a shrinking/stretching surface near the stagnant point is considered. Mass and heat transfer characteristics are incorporated in the problem. A model of the partial differential expressions is altered into the forms of the ordinary differential equations via similarity transformations. The obtained equations are numerically solved by a shooting scheme in the MAPLE software. Dual solutions are observed at different values of the specified physical parameters. The stability of first and second solutions is examined through the stability analysis process. This analysis interprets that the first solution is stabilized and physically feasible while the second one is un-stable and not feasible. Furthermore, the natures of various physical factors on the drag force, skin-friction factor, and rate of mass and heat transfer are determined and interpreted. The micropolar nanofluid velocity declines with a rise in the suction and magnetic parameters, whereas it increases by increasing the unsteadiness parameter.The temperature of the micropolar nanofluid rises with increase in the Brownian motion,radiation, thermophoresis, unsteady and magnetic parameters, but it decreases against an increment in the thermal slip constraint and Prandtl number. The concentration of nanoparticles reduces against the augmented Schmidt number and Brownian movement values but rises for incremented thermophoresis parameter values. 相似文献
8.
A. F. Kolesnikov 《Fluid Dynamics》1993,28(1):131-137
The problem of local simulation of stagnation point heat transfer to a blunt body is solved within the framework of boundary layer theory on the assumption that the simulation subsonic high-enthalpy flow is in equilibrium outside the boundary layer on the model, while the parameters of the natural flow are in equilibrium at the outer edge of the boundary layer on the body. The parameters of the simulating subsonic flow are expressed in terms of the total enthalpyH
0, the stagnation point pressurep
w
and the velocityV
1 for the natural free-stream flow in the form of universal functions of the dimensionless modeling coefficients=R
m
*
/R
b
*
( .<1),=V
1/2H
0
( .<1) whereR
m
*
and R
b
*
are the effective radii of the model and the body at their stagnation points. Approximate conditions for modeling the heat transfer from a high-enthalpy (including hypersonic) flow to the stagnation point on a blunt body by means of hyposonic (M1) flows, corresponding to the case 21, are obtained. The possibilities of complete local simulation of hypersonic nonequilibrium heat transfer to the stagnation point on a blunt body in the hyposonic dissociated air jets of a VGU-2 100-kilowatt induction plasma generator [4, 5] are analyzed.Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.1, pp. 172–180, January–February, 1993. 相似文献
9.
《应用数学和力学(英文版)》2019,(8)
The wavelet approach is introduced to study the influence of the natural convection stagnation point flow of the Williamson fluid in the presence of thermophysical and Brownian motion effects. The thermal radiation effects are considered along a permeable stretching surface. The nonlinear problem is simulated numerically by using a novel algorithm based upon the Chebyshev wavelets. It is noticed that the velocity of the Williamson fluid increases for assisting flow cases while decreases for opposing flow cases when the unsteadiness and suction parameters increase, and the magnetic effect on the velocity increases for opposing flow cases while decreases for assisting flow cases. When the thermal radiation parameter, the Dufour number, and Williamson's fluid parameter increase, the temperature increases for both assisting and opposing flow cases. Meanwhile, the temperature decreases when the Prandtl number increases. The concentration decreases when the Soret parameter increases, while increases when the Schmidt number increases. It is perceived that the assisting force decreases more than the opposing force.The findings endorse the credibility of the proposed algorithm, and could be extended to other nonlinear problems with complex nature. 相似文献
10.
O. D. Makinde 《Meccanica》2012,47(5):1173-1184
This paper examined the hydromagnetic mixed convection stagnation point flow towards a vertical plate embedded in a highly
porous medium with radiation and internal heat generation. The governing boundary layer equations are formulated and transformed
into a set of ordinary differential equations using a local similarity approach and then solved numerically by shooting iteration
technique together with Runge-Kutta sixth-order integration scheme. A representative set of numerical results are displayed
graphically and discussed quantitatively to show some interesting aspects of the pertinent parameters on the dimensionless
axial velocity, temperature and the concentration profiles, local skin friction, local Nusselt number and local Sherwood number,
the rate of heat and mass transfer. Good agreement is found between the numerical results of the present paper with the earlier
published works under some special cases. 相似文献
11.
12.
The effect of melting heat transfer on the two dimensional boundary layer flow of a micropolar fluid near a stagnation point embedded in a porous medium in the presence of internal heat generation/absorption is investigated. The governing non-linear partial differential equations describing the problem are reduced to a system of non-linear ordinary differential equations using similarity transformations solved numerically using the Chebyshev spectral method. Numerical results for velocity, angular velocity and temperature profiles are shown graphically and discussed for different values of the inverse Darcy number, the heat generation/absorption parameter, and the melting parameter. The effects of the pertinent parameters on the local skin-friction coefficient, the wall couple stress, and the local Nusselt number are tabulated and discussed. The results show that the inverse Darcy number has the effect of enhancing both velocity and temperature and suppressing angular velocity. It is also found that the local skin-friction coefficient decreases, while the local Nusselt number increases as the melting parameter increases. 相似文献
13.
Investigation of flow and heat transfer of nanofluid in microchannel with variable property approach
Laminar flow and heat transfer of water-Al2O3 nanofluid under constant heat flux have been investigated numerically. Single-phase with temperature dependant effective properties has been assumed for fluid. Enhancement in heat transfer and increase in friction factor have been obtained by the use of nanofluid. Heat transfer enhancement is more obvious by the use of variable properties. Also, effects of temperature variation on nanofluid heat transfer are greater than the pure water. 相似文献
14.
Dr. R. S. R. Gorla 《Heat and Mass Transfer》1988,22(1-2):37-44
An analysis is presented for the transient thermal response of a laminar boundary layer in the vicinity of an axisymmetric stagnation flow on an infinite circular cylinder. The final approach to steady state temperature field is shown to have exponential decay with time. The characteristic factors appearing in the exponents result in the solution of an eigenvalue problem in ordinary linear differential equations. Numerical results are presented for a range of values of the Reynolds number and Prandtl number. 相似文献
15.
The present paper studies the effect of rotation on the thermal instability in a horizontal layer of a Newtonian nanofluid which incorporates the effect of Brownian motion along with thermophoresis. In order to find the concentration and the thermal Nusselt numbers for unsteady state, a nonlinear analysis, using a minimal representation of the truncated Fourier series of two terms, has been performed. The results obtained are then presented graphically. It is observed that rotation delays the rate of heat and mass transferred, representing a delay in the onset on convection. This shows a stabilizing effect for a rotating system against a nonrotating system. 相似文献
16.
Summary An analytical study has been made to determine the heat transfer characteristics of a stagnation point flow in which there are temperature-dependent heat sources or sinks. Results have been obtained for both strong and weak sources or sinks for a Prandtl number of 0.7. An analytical method, applicable to all Prandtl numbers, was utilized which circumvented the need for extensive numerical solutions and which, at the same time, provided a closed-form representation for the heat transfer. A few numerical solutions were carried out to verify the method.Nomenclature
a
i
constants depending on Prandtl number
-
c
p
specific heat at constant pressure
-
f
dimensionless velocity variable
-
g
function defined by equation (13)
-
g
n
functions of (n=1, 2, 3,...)
-
k
thermal conductivity
-
Pr
Prandtl number, c
p
/k
-
q
heat transfer rate per unit area at surface
-
Q
heat flux parameter, q/k(u
1/)1/2
-
S
rate of heat generation or removal per unit volume (divided by c
p
)
-
T
static temperature; T
w
, wall temperature; T
, free-stream temperature
-
u
1
proportionality constant for free-stream velocity
-
U
free-stream velocity
-
v
normal velocity component
-
x
coordinate measuring distance along surface from stagnation point
-
y
coordinate measuring distance normal to surface
-
heat generation parameter, equation (3)
-
dimensionless normal coordinate,
-
dimensionless temperature
-
n
functions of (n=1, 2, 3,...)
-
absolute viscosity
-
kinematic viscosity
-
density 相似文献
17.
S. S. Chentsov 《Fluid Dynamics》1983,18(6):875-882
A method is developed for calculating the intensification of heat transfer in the neighborhood of a stagnation point (line) of a body in a turbulent (uniform or jet) flow. Conditions for the onset of intensification of heat transfer are found for the first time, together with a universal dimension-less number that determines the intensification coefficient. The results of a calculation agree with the existing experimental data for different classes of flows. 相似文献
18.
It is shown that the presence in the boundary layer of components with absorption cross sections that are nonzero in the visible region of the spectrum leads to an increase in the radiant flux reaching the surface as compared with the flux reaching the outer edge of the boundary layer. Conditions permitting the determination of the wavelength intervals on which this effect occurs at any values of the optical thicknesses of the boundary layer are obtained. A criterion, from which it follows that in many flow regimes the effect of vapor injection on the increase of the radiant flux reaching the wall can be neglected, is presented.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 21–30, September–October, 1971. 相似文献
19.
The unsteady double diffusion of the boundary layer with the nanofluid flow near a three-dimensional(3 D) stagnation point body is studied under a microgravity environment. The effects of g-jitter and thermal radiation exist under the microgravity environment, where there is a gravitational field with fluctuations. The flow problem is mathematically formulated into a system of equations derived from the physical laws and principles under the no-slip boundary condition. With the semi-similar tran... 相似文献
20.
The magnetohydrodynamic(MHD) stagnation point flow of micropolar fluids 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 presentation 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. 相似文献