# Analysis of a Novel Fluidic Oscillator under Several Dimensional Modifications
## 6 Results
### Outlet Width Modification
These details can be seen in the videos given in the appendix as Supplementary Materials and will be carefully addressed in the final section of the paper. The unsteady stagnation pressure measured at the MC outlet lower inclined wall is presented in Figure 12(a), from where it can clearly be seen that as the outlet width is reduced, the time-averaged value and the peak-to-peak amplitude at the MC outlet inclined wall raise. In fact, the time-averaged pressure at the entire MC and FC's also increases. The time-averaged evolution of the unsteady pressure at the MC outlet inclined wall, as well as its peak-to-peak amplitude for all outlet widths studied is presented in Figure 12(b). When comparing the minimum and maximum outlet widths, time-averaged and peak-to-peak pressure increases of almost 2.3% and 76%, respectively, are observed. A very similar trend is observed when analyzing the unsteady and time-averaged pressure momentum term at the lower FC outlet (see Figure 12(c),d). Notice that the time-averaged and peak-to-peak values increase (when comparing the minimum and maximum outlet widths), is almost 2% and 74%, respectively, again suggesting a direct correlation between the stagnation pressure at the MC inclined walls and the one at the FC outlet. The mass flow momentum term measured at the lower FC outlet is introduced in Figure 12(e). As already observed when evaluating the different Reynolds numbers, the mass flow momentum term is over two orders of magnitude smaller than the pressure momentum one (compare the figures in Figure 12(e),c), therefore indicating the jet's high sensitivity to the pressure forces. However, when considering the instantaneous mass flow and pressure momentum terms at both feedback channels outlets, it is observed that the net momentum acting on the jet as it enters the mixing chamber is rather small (Figure 12(f)) its peak-to-peak value being about three times larger than the mass flow momentum one measured at the lower FC outlet. Notice as well that the net momentum is rather constant for the different outlet widths studied since the pressure drop between both FC outlets slightly changes with the outlet width modifications considered in the present study. At this point, it is relevant to highlight that if the net forces acting on the jet as it enters the MC suffer a minor variation for the different outlet widths studied (Figure 12(f)), but the FO outlet mass flow peak-to-peak amplitude drastically grows with the outlet width (Figure 12(a)). Such growth needs to be associated with the freedom the main jet has with the outlet width increase. In order to determine the main contributor of the jet self-sustained oscillations, the instantaneous pressure momentum term evaluated on both FC outlets is presented for the minimum (outlet 1) and maximum (outlet 6) outlet widths in Figure 12(a),b, respectively. For comparison, the unsteady mass flow momentum measured at the same locations and for the same outlets is also presented in the same two figures. Figure 14: Instantaneous momentum pressure and mass flow terms measured at both feedback channels outlet sections and for the minimum and maximum outlet widths studied. (**a**) Minimum outlet width (outlet 1). (**b**) Maximum outlet width (outlet 6). Figure 13: Unsteady stagnation pressure measured at the mixing chamber lower inclined wall (**a**), time-averaged values and peak-to-peak amplitudes (**b**). Pressure momentum terms measured at the FC lower outlet (**c**) and their respective average values and peak-to-peak amplitudes (**d**). Dynamic mass flow momentum terms measured at the FC lower outlet (**e**) and the instantaneous net momentum obtained when considering pressure and mass flow momentum terms at both FC outlets (**f**). All graphs consider three different outlet widths, the smallest (outlet 1), the standard case (STD) = (outlet 3), and the largest one (outlet 6) studied in the present study. For the smallest outlet width considered (outlet 1), the peak-to-peak pressure momentum term is about 270% larger than the mass flow one.