Influence of exit configuration on the flow fields and oscillation characteristics inside and outside the fluidic oscillator

Abstract

The fluidic oscillator shows very promising outcomes as an actuator in active flow control applications as it features several characteristics including no-moving parts, self-excitation, rigidity and reliability. The fluidic oscillator can be utilized in diverse applications including active-control of combustion and flow separation. The present work investigates the exit configuration influence on the flow dynamics of a small-scale double-feedback fluidic oscillator. Three configurations were modelled to examine the effects of the inclusion of a splitter inside the exit channel as well as the whole elimination of both the exit channel and splitter. Experimental results were obtained using particle image velocimetry (PIV) laser system with water as a working fluid and time-resolved pressure measurements using a hydrophone. Two-dimensional computational models based on Unsteady Reynolds-averaged Navier-Stokes (URANS) equations and shear stress transport (SST) were utilized considering the flow to be turbulent, incompressible, and isothermal. The results indicate that the exit configuration has no significant effects on the frequencies, while the jet deflection angle of the outflowing jet increases and the jet tends to be continuous when the splitter is removed. The splitter increases the outflow fluctuation amplitudes which would be suitable for diverse applications.