Journal of Engineering for Gas Turbines and Power · 1986 · 65 citations · 0 references
EngineeringAerospace EngineeringPhysicsAcousticsAerodynamicsPropulsionAeroacousticsJet PropulsionAeroacoustic ExcitationExcitationJet Flow ExperimentsJetsStrouhal NumberUpper Limit Estimation
The study measured entrainment of acoustically pulsed axisymmetric air jets into ambient air across various orifice sizes, Strouhal numbers, and excitation powers. Entrainment increased up to 5.8 times beyond 15 diameters downstream, varied linearly with distance, rose nonlinearly with excitation strength suggesting a practical upper limit, and peaked at a Strouhal number of about 0.25.
Direct measurements of entrainment by acoustically pulsed axisymmetric air jets flowing into surrounding air have been made for a range of orifice sizes, Strouhal numbers, and excitation powers. The entrainment was considerably increased, by up to 5.8 times at distances greater than 15 diameters axially downstream of the orifice exit plane. The entrainment of the excited jet varied linearly with downstream distance. The jet response varied nonlinearly with excitation strength, indicating that there may be a practical upper limit to the acoustic augmentation of entrainment. The response depends on Strouhal number and appears to be optimum at about 0.25.