Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 13, 2020 - September 16, 2020
The von Kármán swirling flow is analyzed in terms of the energy cascade mechanism and spatio-temporal fluctuation dynamics. The system consists of a cylinder filled with fluid and inversely rotating disks on both ends. It is known that the flow exhibits different characteristics depending on the stirring mechanism (Cadot et al., Physical Review E, 1997). In the numerical simulation, a “viscous stirring” system with smooth disks is computed via the Spectral Element-Fourier Method. The analysis through the energy equation reveals that the system can be decomposed to two regions; namely, the “boundary” region, where the energy input Pvis(t) and the energy dissipation ∈(t) synchronize well, and the “bulk” region, where time-delayed correlation is observed between them. In the experiment, an “inertial stirring” with bladed disks is analyzed by particle image velocimetry for higher Reynolds numbers to capture a long temporal correlation with the order of 10T, where T is the rotation period of disks.
