Graduate School of Human and Environmental Studies, Kyoto University
School of Earth Sciences, HIS, Kyoto University
temperature-dependence of viscosity on one-dimensional flows are analyzed.
When hot fluid cooled as it flows, velocity-pressure characteristic curve represents negative inclination in certain region. In this negative differential resistance region, the pressure drop decreases with increased velocity. On two and three parallel channels model, negative differential resistance causes bifurcation of the solution. In this case, there are multiple steady flows with inhomogeneous velocity distribution besides homogeneous one. Stableness of some inhomogeneous flows and unstableness of homogeneous one are shown by numerical analyses. At last, the way of the bifurcation is described in a fixed law.
Received 23 October 2001, accepted 9 November 2001