# Analysis of a Novel Fluidic Oscillator under Several Dimensional Modifications
###### Abstract
To accomplish this, they utilized 2D compressible simulations with the sonicFoam software and applied the k-epsilon turbulence model. Significantly, their results revealed a reverse linear correlation between frequency and the length of feedback loops. More precisely, decreasing the length of the feedback channel resulted in an increase in frequency. In 2018, [PERSON] and [PERSON] [22] performed a three-dimensional numerical simulation using the SST turbulent model on the identical configuration previously employed by [14]. In this iteration, a single exit was employed, and the investigation was carried out at a Reynolds number of 30,000. Two geometric parameters, specifically the inlet and outlet widths of the mixing chamber, underwent adjustments. Significantly, modifying the inlet width had a significant influence on both the flow structure and the flow rate within the feedback channel, whereas minimal effects were noted when adjusting the outlet width. Investigating the impacts of changing the lengths of the feedback channel (FC) and the mixing chamber (MC) on output frequency and amplitude was performed by [PERSON] et al. [23]; they utilized a 2D numerical model in 2018. The simulations were conducted assuming incompressible flow with a Reynolds number of 5000. Intriguingly, it was noted that elongating the feedback channel length did not bring about any alterations in the output frequency. This observation had been previously noted by [24], and both studies adopted incompressible flow assumptions, limiting the precision of the simulations in delivering precise information. In contrast, elongating the length of the mixing chamber resulted in a noticeable decrease in the actuator's output frequency. [PERSON] and [PERSON] [25] developed a 3D simulation for a 3D fluidic oscillator. They implemented a comprehensive analysis on the forces driving the oscillations. In 2020, they used the same model and studied the effect of several design modifications [26]. [PERSON] et al. [27] studied the effect of feedback channel (FC) length on FO performance for compressible flow conditions; they found that at large feedback channel lengths, the former main oscillation tends to disappear, the jet inside the mixing chamber simply fluctuates at high frequencies, and as the feedback channel (FC) length exceeds a certain threshold the FO stops oscillating. In [PERSON] et al. [28], a novel shape of a fluidic oscillator (FO) in the laminar regime at a very low Reynolds number was studied; they observed that the jet sweeping angle amplitude is more pronounced for a two-dimensional FO as compared to a three-dimensional one at a fixed given Reynolds number, and the instability of the output jet becomes slightly chaotic at very low Reynolds numbers. In recent years, many researchers have been working on the analysis, design, and applications of FOs. For instance, [PERSON] et al. [29], performed a numerical study of the influence of jet parameters of fluidic oscillator-type fuel injector on the mixing performance in a supersonic flow field. Their results showed that the influence of the sweeping jet angle on the mixing performance is more notable than that of the oscillating frequency, and they concluded that an appropriate combination of the frequency and sweeping jet angle is needed to maximize the mixing performance. In another attempt, [PERSON] et al. [30] conducted a numerical investigation for enhancing a subsonic ejector performance by incorporating a fluidic oscillator as the primary nozzle. Their results indicated that a harmonically oscillating primary flow was generated, increasing the mixing entrainment and momentum transfer while reducing the pressure in the suction and mixing chambers. A microfluidic actuator was studied at high Reynolds numbers in [31], where 2D-URANS simulations along with experimental results and a final 3D CFD simulation was performed. Coherent structures as well as turbulent kinetic energy fields and velocity contours were used to unveil the associated complex fluid dynamics.