Summary
The development of the velocity profile, from a uniform one at the entrance, for an electrically conducting fluid entering a semi-infinite flat duct with a transversely applied magnetic field is investigated. It is assumed that the fluid has constant physical properties, the duct walls are electrically nonconducting, a uniform magnetic field is imposed perpendicular to the duct walls, and there can be a net electrical current flow parallel to the walls and perpendicular to the flow direction with a variable external resistance connecting the two side plates, which are displaced at infinity. The basic governing continuity and momentum equations are expressed in finite difference form and solved numerically on a high-speed digital computer with a mesh network superimposed on the flow field. A practical mesh size ratio suitable for computation was determined. Results were obtained for the variations of velocity and pressure distribution between the inlet and the region for the fully developed velocity profile for Hartmann numbers of 0, 4, and 10.
Similar content being viewed by others
Abbreviations
- a :
-
duct half-height
- B :
-
magnetic induction, B = μ e H
- C :
-
friction factor defined in equation (15)
- D e :
-
diameter, D e = 4 × area/perimeter
- e :
-
electric field magnitude factor, E 0 = − eu 0 B 0
- E :
-
electric field strength
- H :
-
magnetic field intensity
- K :
-
constant defined in equation (15)
- J :
-
electric current density
- M :
-
Hartmann number, M = μ e H 0 a[σ e /ρν]1/2
- p :
-
fluid pressure
- p 0 :
-
pressure at channel mouth
- P :
-
dimensionless pressure, (p - p 0)/ρ u 0 2
- ΔP:
-
pressure defect, (p 0 - p)/(ρ u 0 2/2)
- Re a :
-
Reynolds number, ρ u 0 a/μ
- s :
-
duct height
- t :
-
time
- u :
-
fluid velocity in x-direction
- u 0 :
-
fluid velocity at inlet
- U :
-
dimensionless u velocity, u/u 0
- u :
-
fluid velocity in y-direction
- V :
-
dimensionless u velocity, av ρ /μ
- x :
-
coordinate along channel
- X :
-
dimensionless x-coordinate μx/ ρ a 2 u 0 = (x/a)/Re a
- X′:
-
dimensionless x-coordinate, as μx/ρ s 2 u 0 = X/4
- y :
-
coordinate across channel
- Y :
-
dimensionless y-coordinate, y/a
- v :
-
kinematic viscosity
- ρ :
-
fluid density
- μ :
-
dynamic viscosity
- μ e :
-
magnetic permeability
- σ e :
-
electric conductivity
References
Hwang, C. L., Ph. D. Thesis, Mech. Engg. Dept., Kansas State University, July 1962.
Roidt, M. and R. D. Cess, J. Appl. Mech. Trans. ASME, 84 (1962) 171.
Schlichting, H., Boundary Layer Theory, 4th ed., McGraw-HilI Book Company, New York, 1960, p. 169–171.
Bodoia, J. R., Ph. D. Thesis, Carnegie Institute of Technology, July 1959.
Bodoia, J. R. and J. F. Osterle, Appl. sci. Res. A10 (1961) 265.
Lapidus, Leon, Digital Computation for Chemical Engineers, McGraw-Hill Book Company, New York, 1962, p. 158, 246–247.
Grandy, R. A., The Aeronutronic Hop Program for Fluid Flow, AFSWC TN-61-29, Part 1, AFSWC Second Hydrodynamic Conference, Numerical Methods of Fluid Flow Problems, May 1961, p. 88–95. (available from Library of Congress).
Kays, W. M., Numerical Solutions for Laminar Flow Heat Transfer in Circular Tubes, Tech. Report No. 29, Mech. Engg. Dept., Stanford University, October 1953, p. 15.
Cowling, T. G., Magnetohydrodynamics, Interscience Publishers, New York, 1957, p. 2–17.
Shercliff, J. A., Proc. Cambridge Phil. Soc. 52 (1956) 573.
Goldstein, S., Modern Developments in Fluid Dynamics, I, Oxford University Press, Oxford, 1950, p. 309.
Han, L. S., J. Appl. Mech. Trans. ASME, Series E, 82 (1960) 403.
Eckert, E. R. G. and R. M. Drake Jr., Heat and Mass Transfer, 2nd ed., McGrawBook Company, New York, 1959, p. 172.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Hwang, CL., Fan, LT. A finite difference analysis of laminar magneto-hydrodynamic flow in the entrance region of a flat rectangular duct. Appl. sci. Res. 10, 329–343 (1963). https://doi.org/10.1007/BF03177939
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF03177939