Stability Regimes of Flow in a Channel between Coaxial Cylinders

Resumo

The stability of spiral flow occurring in the simultaneous presence of a pressure difference in the channel between two coaxial cylinders and rotation of one of the cylinders is studied. It is shown that depending on the azimuthal Reynolds number the modes with different azimuthal wavenumbers can be most unstable. The data of calculations are in good agreement with the available experimental data. It is shown that certain experimental results correspond to the earlier unknown regime of the zeroth azimuthal mode instability. The stability characteristics of spiral flow of a nanofluid based on water with zirconium oxide particles are studied. In all the cases considered the nanofluid is less stable than the baseline fluid. The degree of nanofluid flow destabilization increases with increase in the particle concentration and a decrease in their dimensions.