Enhancement of laminar flow mixing using a pair of staggered lateral synthetic jets

• A lateral synthetic jet pair operated 180° out-of-phase is used.
• An excellent inline mixing is achieved at a net flow Reynolds number of 83.
• Staggered jet orifice configuration is more effective at a moderate level of actuation frequencies or amplitudes.
• The dominant mixing mechanism changes as actuation parameters vary.

In the work reported in this paper, laminar flow mixing between two parallel water streams, which are injected into a rectangular channel at a net flow Reynolds number of 83, is enhanced using a pair of staggered lateral synthetic jets (LSJ) located on the opposite walls of the mixing channel. The synthetic jet pair is operated 180° out-of-phase at a range of actuation frequencies, f, and dimensionless stroke length, L. Our results show that an excellent mixing is obtained when a relatively high value of f or L is used. The dominant mixing enhancement mechanisms are identified, which are found to change as the LSJ actuation parameters vary. Quantitative comparison with the opposing LSJ pair configuration reveals that the staggered configuration slightly outperforms the opposing configuration at moderate levels of f or L. As f or L increase further, however, a similar mixing performance is obtained from both configurations.