# Analysis of a Novel Fluidic Oscillator under Several Dimensional Modifications
## 6 Results
### Mixing Chamber Internal Angle Modification  
The present section clarifies the fluidic oscillator performance when the mixing chamber inlet angle is modified; the main details of the different MC angles studied were already specified in Table 4. As in the previous subsection, the Reynolds number will be kept constant at \(Re=54\),595. The fluidic oscillator outlet unsteady mass flow for the mixing chamber minimum and maximum angles (Angle 1) and (Angle 3), respectively, and for the standard one (STD), are presented in Figure 16a. The time dependent feedback channel mass flow measured at the lower feedback channel outlet and for the same three mixing chamber angles is introduced in Figure 16b. As the mixing chamber angle increases, the peak-to-peak amplitude of the FO outlet mass flow as well as its associated frequency keep increasing. An opposite effect is observed on the FC mass flow: since the peak-to-peak amplitude decreases with the MC angle increase--also decreasing the maximum reverse flow in the feedback channels--the frequency increases. The outlet mass flow peak-to-peak amplitude and frequency increase when comparing the minimum (Angle 1) and maximum (Angle 3) angles studied, which are 46% and 15%, respectively, and the corresponding FC mass flow amplitude decrease and frequency increase are 65% and 19.5% respectively. It is perhaps more interesting to highlight the fact that the maximum outlet mass flow appears when the jet leaving the mixing chamber is experiencing either its maximum or minimum inclination angle versus the horizontal axis; this is more clearly observed when looking at the videos (see appendix as Supplementary Materials). In fact, the same phenomenon was happening in Figure 7a for different Reynolds numbers and in Figure 12a for different outlet widths. Notice that for these two figures as well as for Figure 16a, the respective minimum mass flows obey to the instants the jet leaving the FO flows horizontally. Two maximum consecutive peaks characterize the instants at which the jet leaving the FO generate the maximum angles, whether positive or negative, versus the horizontal axis. This is why in all these graphs the FC mass flow seems as if the corresponding frequency was half of that of the FO outlet mass flow. A  
Figure 16: Fluidic oscillator outlet unsteady mass flow (**a**) and feedback channel mass flow (**b**), for the smallest mixing chamber internal angle (Angle 1), the largest MC internal angle (Angle 3), and the standard case (STD). final remarkable detail to be observed in Figure 16b is that the reverse flow (flowing from the FC outlet towards the FC inlet) keeps decreasing with the increase in the MC angle. It appears as if a higher freedom in the movement associated with the jet inside the mixing chamber reduces the reverse flow in the feedback channels, although in reality, this effect will be more clearly understood when analyzing the pressure at the mixing chamber outlet inclined walls. At this point, it is relevant to compare the effects on the FC mass flow when the FO outlet width is increased and when the MC internal angle is increased (see Figure 12b and Figure 16b). When increasing the FO outlet width, it generates a negligible effect on the FC mass flow peak-to-peak amplitude, but this reduces when increasing the MC inlet angle. In both cases, the outlet mass flow amplitude increases, and in both cases, the jet inside the MC has a higher degree of movement. Yet, the increase in the MC internal angle affects both the FC mass flow and the FO mass flow amplitude while the increase in the FO outlet width just affects the FO outlet mass flow, probably due to the fact that the degree of freedom inside the mixing chamber remains quite unchanged.