Hydrodynamic instability of nanofluids in round jet for small Stokes number

Abstract

The flow instability of particle-laden jet has been widely studied for large Stokes numbers. However, there is little attention on the case with small Stoke number, which often occurs in practical applications with nanoparticle-laden fluid. In this paper, the instability of nanofluids in round jet is studied numerically for [Formula: see text]. The results show that the law of nanofluids instability is quite similar to regular particle instability for axisymmetric azimuthal mode [Formula: see text]. However, for asymmetric azimuthal mode [Formula: see text], the regular pattern of instability is quite complex and different compared to common particle instability. The variations of wave amplification with wave number for different jet parameter [Formula: see text], Reynolds number Re, particle mass loading [Formula: see text], Knudsen number Kn, Stokes number St and the azimuthal modes [Formula: see text] are given. The flow usually gets more unstable as Knudsen number Kn increases, but the varying law gets inverse at high Reynolds number and at [Formula: see text]. The flow gets more unstable as Stokes number St increases at [Formula: see text] but gets more stable at [Formula: see text]. The decreases in wave number stimulate the flow instability at [Formula: see text] which shows distinct difference for the case at [Formula: see text]. Some unusual results of the effect of B, Re, Z on the flow instability are also discussed.