An Optimization Study of Multi-Orifice Synthetic Jets

From the mixing of creamer into coffee, to the dynamics of a dust storm, or smoke rising from a chimney—everything is driven by turbulent fluid motion. Experimentalists bring the complex driving mechanism that is turbulence into a laboratory setting to fundamentally understand its behavior in response to certain test parameters. Researchers may choose various drivers, or “actuators”, of fluid motion to start the turbulent regime for their applications. However, in building an entire experimental apparatus, they miss the step of ensuring that an individual driver is performing as best as possible. A common actuator used in experimental studies is a turbulent jet that produces fluid from a nozzle that stirs up the surrounding medium. One such turbulent jet that is very compact and adaptable is a synthetic jet. In this study, we use the frequency and amplitude of the loudspeaker that drives the synthetic jet to modulate the energy injected into the fluid medium. The review of established literature has additionally guided the design of novel nozzle geometries that create a high degree of turbulent motions that are well-dispersed in the environment. Vector fields are quantified with special high-speed cameras that observe these small-scale fluid motions. This together with a monitor of loudspeaker performance serves to show how the flow issuing from an actuator evolves in space. For a facility of a certain dimension, researchers can then fix key parameters to create desired fluid motions for the lowest operating cost.