© 1999 by Oxford University Press
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Behaviour of a non-local reactive convective problem modelling ohmic heating of foods
( A1 Department of Mathematics, Heriot-Watt University, Edinburgh EH14 4AS, UK A2 Department of Mathematics, National Technical University of Athens, Zografou Campus 157 80, Greece )
We consider the non-local problem,
ut + ux =
f(u) / (
01f(u)dx)2, 0 < x <1,
which models the temperature when an electric current flows through a moving material with negligible thermal conductivity. The potential difference across the material is fixed but the electrical resistivity f(u) varies with temperature. It is found that, for f decreasing with
0
f(s)ds <
, blow-up occurs if
is too large for a steady state to exist or if the initial condition is too big. If f is increasing with
0
ds/f(s) <
blow-up is also possible. If f is increasing with
0
ds/f(s) =
or decreasing with
0
f(s) s =
the solution is global. Some special cases with particular forms of f are discussed to illustrate what the solution can do.