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National Advisory Committee for Aeronautics, Technical Notes - On Flow of Electrically Conducting Fluids Over a Flat Plate in the Presence of a Transverse Magnetic Field

The use of a magnetic field to control the motion of electrically
conducting fluids is studied. The boundary-layer solutions are found
for flow over a flat plate when the magnetic field is fixed relative to
the plate or to the fluid. Toe equations are integrated numerically for
the effect of the transverse magnetic field on the velocity and temperature
profiles, and hence, the skin friction and rate of heat transfer.

It is concluded that the skin friction and the heat-transfer rate are
reduced when the transverse magnetic field is fixed relative to the plate
and increased when fixed relative to the fluid. The total drag is
increased in all the cases studied.

It has been said that a fluid at a very high temperature is like a
universal solvent which cannot be contained. A possible method of con-
taining this fluid is suggested when it is noted that at such a high
temperature it would surely contain ions and. quite probably also free
electrons. The fluid would then be an electrical conductor. The invis-
ible hand of electrical and magnetic fields can then be used to induce
forces on the fluid such that it is prevented from coming in direct contact
with a wall which it would dissolve.

Asomewhat similar techniquehasbeeninuse forsometimeinthe
metal purification industry. It employs a high-frequency magnetic field
which causes eddy currents in a lump of molten metal which in turn react
with the imposed magnetic field. The metal is thereby suspended in space
if the imposed magnetic field is made strong enough.

Another example is the so-called “perhapsatron” described briefly in
reference 1. A gas in a dougnnut shaped container is heated to a big:
temperature by an electrical current discharge. Through the use of the
interaction of the resulting ion current and a magnetic field, the hot
gas is prevented from coming in contact with the surface of the vessel.
An application of similar principles was used. in thermonuclear fusion
experiments in the Soviet Union. The techniques and. results described
very briefly in reference 2 indicate that it was possible to keep the hot
fluid from the walls and to concentrate the hot gases quickly so as to
generate a focusing shock wave.