半径方向に温度勾配をもつ回転二重円筒管流れの不安定(回転(1),一般講演)

概要

論文の詳細を見る
We investigate the stability of the basic flow produced by imposing radial temperature gradient in a rotating annulus, theoretically and experimentally. Linear stability analysis shows that the rotation destabilize the basic flow and leads to spiral vortex flows with different slope: nearly horizontal at low rotation rate, whereas nearly vertical at high rotation rate. For each of the two regimes, we obtain nonlinear secondary flows and consider their linear stability. Tertiary flow for nearly-vertical spiral mode is also obtained. We observed the nearly-vertical spiral mode in the experiments using a rotating annular tank with radius ratio of 0.9 and aspect ratio of 56. The spiral vortices are always transient and eventually develop into nonstationary kinked vortices. When the Grashof number (temperature difference across the annular gap) is small, characteristics of the spiral vortex at the initial stage is in good agreement with theoretical results.
2008-09-04