An exact solution is found for a non-linear problem with thermomechani
cal coupling, the steady flow of a fluid with viscosity exponentially
dependent on temperature, which is sheared between an adiabatic, fixed
, inner cylinder and a thermostatted, rotating, outer cylinder. There
is a maximum torque above which no steady flow is possible and below w
hich two flows are possible, a high shear and a low shear steady flow
for each value of torque.