Chaotic Lagrangian motion in a steady baroclinic wave, which is highly relevant to meteorological and oceanographical problems, was investigated by Sugata and Yoden (1994) by tracing a marked fluid particle for a long time in a numerical solution of their model. To test their result, we have conducted experiments on steady Baroclinic waves in a differentially-heated rotating fluid annulus by tracking a 3-D trajectory of one neutrally buoyant tracer particle suspended in the fluid for a long time. We show here four trajectories that have been analyzed up to now. In the wavenumber-5 wave, the observed trajectories include the preferred routes of region transitions expected from the numerical investigation. This supports the Lagrangian view of the heat transport presented by Sugata and Yoden: The jet absorbs a large number of hot fluid particles from the outer boundary layer and releases them in the inner boundary layer, while the fluid particles nearly conserve their temperature in the meandering jet. Furthermore, it is of great interest that there was found one event of region transtion which does not take place in the numerical simulation. In the wavenumber-4 wave, however, the tracer particle was observed to remain trapped within the jet for a long time. This leads to the orthodox view of the heat transport: The jet absorbs a large amount of heat from the outer boundary and releases it into the inner boundary so that heating and cooling of the fluid particles take place during every cycle of the meander of the jet.

No abstract

No abstract

No abstract

Numerical simulations for a T-pipe consisting of a rectangular duct for main stream and a circular pipe for branch stream were performed to investigate relation between large-scale eddy structure formation in the mixing area and temperature fluctuation generation on the wall. Moreover, the numerical simulation to investigate thermal interaction between fluid and structure were conducted. Experimental results of temperatures at 2mm from the wall in fluid, on the wall and at 3mm inside from the wall in structure were compared with those of the numerical results. The numerical results indicate that the fluid-structure thermal interaction is necessarily considered for thermal fatigue estimation in the thermal striping phenomena.