Impingement heat/mass transfer to hybrid synthetic jets and other reversible pulsating jets

Energetic efficiencies of synthetic and hybrid synthetic jet actuators driven by electrodynamic transducers

“…The advantages of the HSJA are evident: For P e = 0.4-3.2 W, the HSJA achieves a 15-23% increase in the velocities and a 41-48% increase in the energetic efficiency. These results well agree with the previous experiments with the same actuator, which were performed at a bit higher input real power, P e = 4.0 W, see [43,48,55]. Namely, the studies [43, 48, and 55] concluded that the HSJA achieves a 25%, 24%, and 26 % increase of the velocities in comparison with the SJA, respectively.…”

“…Furthermore, it can be concluded that the velocity profiles are relatively flat in both cases (SJ and HSJ). The flat velocity profiles are also presented by Trávníček and Vít [55] who performed measurements with the same actuator at higher input real power (4.0 W). These findings justify the simplifications made in the theory introduced in appendix A, which assumes uniform velocity profiles.…”

“…These findings justify the simplifications made in the theory introduced in appendix A, which assumes uniform velocity profiles. Note that Trávníček and Vít [55] made also a deeper analysis of the SJ/HSJ flows downstream of the nozzle exit and quantified heat/mass transfer in cases of impinging HSJ and SJ concluding an 18% increase of the local heat/mass transfer rate for the HSJ. Integration of the velocity profiles defined by Eq.…”

“…The present synthetic/hybrid synthetic jet actuator (SJA, HSJA) operates with air as the working fluid, and its geometry and electrical connection is identical as in [43], [48], [55]. A sketch of the actuator is shown in Fig.…”

Synthetic and Continuous Jets Impinging on a Circular Cylinder

“…Trávníček and Vít [108] performed a heat transfer study that compared synthetic jets, hybrid synthetic jets, mixed pulsed jets and continuous jets. The enhancement of heat transfer using pulsating jets was shown.…”