Active flow control becomes more and more important in many aerospace applications to meet future economic and environmental requirements. Fluidic oscillators used for flowcontrol are already introduced to the scientific community and their stable and robust operation is very well known. The unsteady excitation effects up to frequencies of several kHz and the reduced mass flow requirements are beneficial compared to steady blowing concepts. The object of investigation is the well-known oscillator design developed at the Institute of Jet Propulsion. The working principle of this actuator is based on two feedback loops and two outlet holes perpendicular to the oscillator plane, generating a high frequency pulsed blowing. This concept features a stable and predictable operation as well as the integration into thin geometries, for instance turbomachinery blades. The scope of this paper are experimental investigations of selected geometric design parameters and their influence on the oscillator performance. The parameters examined in detail are the width of the actuator’s inlet nozzle, oscillator’s channel height, feedback loop length, and linear scaling of the entire geometry. The experiments were carried out at different ambient pressures levels, to cover the full pressure spectrum of turbomachinery operation and flight applications. Depending on the parameter variation and operating point, the range of one actuator is between 2 to 400 mg/s in mass flow, covering pressure ratios from little above 1 to 8, and showing maximum frequencies up to 14 kHz. The ambient pressure level is varied between atmosphere (950hPa) and 50hPa absolute pressure. With the presented results a target-oriented design for a specific flow control application in terms of mass flow rate, pressure ratio, and frequency spectrum can be derived.    «

Active flow control becomes more and more important in many aerospace applications to meet future economic and environmental requirements. Fluidic oscillators used for flowcontrol are already introduced to the scientific community and their stable and robust operation is very well known. The unsteady excitation effects up to frequencies of several kHz and the reduced mass flow requirements are beneficial compared to steady blowing concepts. The object of investigation is the well-known...    »