The objective in this project is to establish a novel approach for choosing separation control parameters that lead to a significant reduction of the mass flow consumption while retaining the control authority.
Based on experimental techniques, characteristic vortical structures und underlying physical mechanisms associated with pulsed jets have been revealed (Figure 1). As a major finding, a flow-inherent time scale governing the recurrence of flow separation subsequent to the momentum addition by means of pulsed jets has been identified in a generic setup. This gave rise to significant mass flow savings by adjusting the time delay separating successive pulses. These findings have corroborated an initial hypothesis inasmuch as a reduction the actuation duty cycle indeed leads to systematic efficiency gains.
Future studies will be aimed at transferring the approach to a flow configuration that is more relevant to the aerodynamics community while addressing practical issues that arise in such applications. We hope that the findings obtained in this project will allow for a more informed choice of operating parameters in future separation control applications
Steinfurth, B. & Weiss, J. 2021 Boundary-layer control by means of pulsed jets at different inclination angles AIAA J. 59(8).
Steinfurth, B. & Weiss, J. 2021 Velocity ratio effect on flow structures of non-parallel planar starting jets in cross-flow J. Fluid Mech. 915.
Steinfurth, B. & Weiss, J. 2020 Vortex rings produced by non-parallel planar starting jets J. Fluid Mech. 903.