1 research outputs found
Annular synthetic jet used for impinging flow mass-transfer
An annular synthetic jet was investigated experimentally, both with and without an
opposing impingement wall. The experiments involved smoke visualization and mass
transfer measurement on the wall by means of naphthalene sublimation technique.
Two qualitatively different flow field patterns were identified, depending upon the
driving amplitude level. With small amplitudes, vortical puffs maintain their identity
for a relatively long time. If the amplitudes are large, breakdown and coalescence of
the vortical train is much faster. Also the resultant mass transfer to the impingement
wall is then much higher. Furthermore, a fundamental change of the whole flow field
was observed at the high end of the investigated frequency range, associated with
radical reduction of the size of the recirculation bubble