Synthetic Jets: Basic Principles

A jet flow is a class of fluid flow in which a stream of one fluid mixes with a surrounding fluidwhichmight be at rest or inmotion. Such flows occur inmany natural and engineered applications. Flow properties for incompressible jets are often greatly dependent on the Reynolds number Re≡UL/ν, where ρ is the fluid density, U is a characteristic velocity (e.g., jet exit velocity), L is a characteristic length scale (e.g., jet diameter), and ν is the kinematic viscosity. In case the flow shows compressible effects (typically for M > 0.3), jet flow characteristics are also affected by the Mach number defined asM ≡ U/c, where c is the speed of sound.