Displacement amplitude scaling of a two-dimensional synthetic jet

Abstract

A two-dimensional synthetic jet is studied numerically by solving the incompressible, unsteady, Reynolds-averaged, Navier-Stokes equations and using a k-⑀ turbulence model. Rather than a resonant cavity, the synthetic jet is supplied by a fully developed channel flow. Results for two exit geometries, a sharp exit and a rounded exit, and several dimensionless stroke lengths are compared. This study focuses on the effect of the displacement amplitude ͑stroke length͒ on the power required to form the jet, the net momentum flux downstream of the exit, the formation threshold, and the spatial development of the synthetic jet. It is shown that the channel flow development length, the self-similar region, and the region from which the jet draws fluid all scale on the stroke length. It is also demonstrated that the power required to form the jet increases with stroke length as does the resultant momentum flux. Finally, the power required to form a synthetic jet is significantly smaller for a rounded exit compared to a sharp-edged exit.

A general correlation for the stagnation point Nusselt number of an axisymmetric impinging synthetic jet

“…due to geometric details like a minor fillet on the outer orifice edge, and higher values (L 0 /D between 1 and 2) are typically reported in experimental studies [16,17]. For a two-dimensional synthetic jet, Fugal et al [30] even observed a five-fold increase in the critical stroke length (from 2 to 10 slot widths) when using a rounded nozzle exit with a radius of 1 slot width. [18] In the absence of jet formation the heat transfer performance tends towards the natural convection regime.…”

General Reduced-Order Model to Design and Operate Synthetic Jet Actuators

“…L d π > [3], with even higher values reported for a rounded edge [4,5]. It is well understood that 0 L d and Re are the main parameters governing a synthetic jet flow [2].…”

Frequency response of a synthetic jet cavity

“…Apart from the above experimental work, some numerical simulations have also been done on synthetic jets [13][14][15]. Most of the simulations reported in the literature are two-dimensional in nature, and usually involve a cross-flow which is important from the point of view of applications.…”