Microsynthetic Jets

Microsynthetic Jets, Fig. 1 Synthetic jet actuator concept (a) ingestion phase (b) expulsion phase... 

Microsynthetic Jets, Fig. 2 Nondimensional vorticity contours and axial velocity profiles at three times during vortex ring formation before the vortex pinch-off, during the pinch-off, and after the pinch-off. Axial velocities at the axial center of the vortex ring regions and close to the... 

Microsynthetic Jets, Fig. 4 Smoke visualization of flow around a circular cylinder in a uniform cross stream. A pair of synthetic jets is closely spaced from each other and is flushed with the cylinder surface, (a) No jet. Base flow appears to separate at (b) In-phase actuation of jets at 60. (c) Jets located at 180. The external flow appears to be... 

Microsynthetic Jets, Fig. 6 (a) Averaged velocity profiles at various distances from the actuator, (b) Centerline velocity drop as a function of distance from the actuator. 

Microsynthetic Jets, Fig. 7 Normalized velocity profiles for experimental and analytical data for a synthetic jet and a conventional turbulent jet. Note that Jivinuai = reai - Xo and is the centerline velocity... 

The momentum injection actuators act like a source of momentum to the flow. One popular approach in this category is blowing. The other popular actuator in this category which does not require any fluid supply is the synthetic jet. The moving surface actuators provide motion of the wall beneath the flow. These actuators inject momentum to the flow by modification of the surface boundary condition. They introduce localized boundary layer disturbances. Hap acmator and balloon actuator belong to the moving surface actuators. The fabrication procedure of microsynthetic jet, microbaUoon, and microflap actuators is established in literature. The practical applications of these actuators have been demonstrated. The present study discusses the details of... 

The physical configuration and the microfabrication procedure of microsynthetic jet, microbaUoon, and microflap actuators are discussed in this section. 

Turbulence Control (Microflap, MicrobaUoon, Microsynthetic Jet), Fig. 2 Schematic of synthetic actuator with (top) ingestion and bottom) expulsion phase... 

The operational characteristics and salient examples of microsynthetic jet, microballoon, and microflap applications have been discussed in the following sections. 

Different nondimensional numbers and their critical value characterize the operation of a microsynthetic jet. Reynolds number and Stokes number are used to describe the viscous and tmsteady effects, respectively. The Reynolds number (Re) is defined based on the maximum jet velocity, U at the exit of the orifice, and orifice diameter (d) as (see Fig. 2)... 

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