A synthetic jet is formed as a consequence of a periodic – say sinusoidal – expulsion and extraction of fluid through an orifice, so that the time-averaged flow rate through the orifice is zero. Despite the zero mean mass flux, the sequence of injection followed by suction results in net momentum and vorticity being released into the fluid body in which the jet is generated. This is, essentiall...

Aerodynamic flow control effected by interactions of surface-mounted synthetic (zero net mass flux) jet actuators with a local cross flow is reviewed. These jets are formed by the advection and interactions of trains of discrete vortical structures that are formed entirely from the fluid of the embedding flow system, and thus transfer momentum to the cross flow without net mass injection across...

Aerodynamic flow control effected by interactions of surface-mounted synthetic (zero net mass flux) jet actuators with a local cross flow is reviewed. These jets are formed by the advection and interactions of trains of discrete vortical structures that are formed entirely from the fluid of the embedding flow system, and thus transfer momentum to the cross flow without net mass injection across...

Zero-mass pulsatile jets are proposed for low speed maneuvering and station keeping of small underwater vehicles. The flow field of such jets are initially dominated by vortex ring formation. Such pulsatile jets can be actuated through a variety of techniques. Two prototypes of such actuators, presented here, include a mechanical plunger system and a solenoid actuator. The actuators consist of ...

A variety of different types of actuators have been previously investigated as flow control devices. Potential applications include the control of boundary layer separation in external flows, as well as jet engine inlet and diffuser flow control. The operating principles for such devices are typically based on either mechanical deflection of control surfaces (which include MEMS flap devices), m...

Topanol A is a phenolic antioxidant additive, which is used in storage tanks for jet fuels produced in the petroleum refineries throughout the country. Topanol A mostly consists of 2,6-di-t-butylphenol. The conventional methods for the preparation of this compound involve ortho-alkylation of phenol using 2-methylpropene (isobutylene) as the alkylating agent. The compound has been prepared by or...

This paper deals with active control of a continuous jet issuing from long pipe nozzle by means concentrically placed annular synthetic jet. The experiments in air cover regimes laminar, transitional, and turbulent main flows (Reynolds number ranges 1082–5181). velocity profiles (time-mean fluctuation components) unforced forced jets were measured using hot-wire anemometry. Six flow are disting...

A numerical investigation is conducted to study flow structures and interactions that are caused by a pitched synthetic jet placed in a laminar (Blasius) boundary layer with zero pressure gradient. Simulations are performed for various permutations of jet parameters including pitch angle (i.e., θ=60, 75, and 90), blowing ratio (i.e., Cb = 0.5, 1.0, 1.5, and 2.0), and non-dimensional actuation f...