On the control of 2D turbulence by active mixing in opposed jets mixers

Abstract

Opposed Jet mixers contact two opposed high-speed streams in a semi-confined mixing chamber. The turbulent energy for mixing is injected from the smaller scales of the inlet streams width and grows into larger vortices extending to the chamber width. The energy distribution associated to the flow scales mainly concentrates in the inertial sub-range, ranging from the injectors width to the mixing chamber width. This energy cascade and respective wavelengths are controlled by the geometry of the mixer. This paper introduces the control of 2D turbulent energy spectrum from an external stimulus, the modulation of the jets flow rate, which induces several dynamic behaviors. A new flow regime is induced from active mixing, where a state of resonance with a single flow frequency throughout the CIJs is associated to the formation of large vortices occupying the entire width of the mixing chamber. This work addresses a novel implementation of CIJs with modulation of inlet flow rate for process intensification of mixing sensitive operations.