Numerical investigation of the oscillating behavior and flow field in a dual self-oscillatory jet under dynamic asymmetric boundary condition

Abstract

In the present study, the flow field of a dual self-oscillatory jet has been investigated at various nozzle-to-nozzle distances and asymmetric inlet boundary conditions. To analyze the flow field in the jet chamber, the two-dimensional unsteady Reynolds averaged Navier–Stokes equations have been solved using the Computational Fluid Dynamics (CFD) method. The CFD code has been developed on the OpenFOAM solver as a finite volume-based tool. Based on the nozzles’ location and inlet flow rates, the flow behavior could be divided into four categories: merged oscillating behavior, non-merged oscillating behavior, non-merged irregular behavior, and non-oscillating behavior. The results indicate that, at merged oscillating behavior, by changing the inlet boundary condition, the Strouhal number, StD, does not change and is StD = 0.025. In the merged oscillating behavior, the combining and merging points are considered as points on the symmetric line with maximum and minimum horizontal mean velocity. The results show that the location of combining and merging points are independent of inlet boundary conditions and move downstream by growing the nozzle-to-nozzle distance.