Transition Process to Turbulence in a Solid-Liquid Two-Phase Confined Jet

The transition of an initially laminar two-phase confined jet has been studied experimentally and analytically. Time series velocity data of both phases were measured by LDV with particle size discrimination. The spectral evolution was discussed to clarify the transition mechanism. Two-phase jet properties were also analyzed using a new mathematical model based on the linear stability theory wherein the interaction force by solid particle motions was taken in account. The resulting eigenvalue problem of the modified Orr-Sommerfeld equation was solved numerically using expansions of Chebyshev polynomials and the modified LR matrix eigenvalue algorithm. The experimental results showed the energy transferred from the mean flow to the disturbance was suppressed in the two-phase flow and as a result, the transition to turbulence was delayed. The numerical analysis indicated that the temporal growth rate of disturbances decreased, and the stability of the flow was enhanced with increasing particle loading ratio.