# Novel Fluidic Oscillator Evaluation Considering Dimensional Modifications
## 6 Results
### Mixing Chamber Angular Modifications (2D-CFD)
Perhaps the first thing to point out is that there is not a direct link between the stagnation pressure variations measured at the MC's lower converging walls and the rest of the parameters, as previously noted in [42] for different Reynolds numbers. Note that the variation in the Reynolds number largely modifies the kinetic energy associated with the fluid particles. However, when modifying the internal angle of the MC, the kinetic energy associated with the flow entering the FO remains constant, while particularly the MC entrance width, and also the FC length, as well as the FC's outlet width, are modified. The fact that the kinetic energy at the FO inlet remains constant, along with the combined effects of the dimensional modifications, is what makes Figure 14 a bit difficult to follow. When analyzing the stagnation pressure evolution at the MC's lower converging wall (Figure 14a,b), it is observed that its time-averaged value, as well as the peak-to-peak amplitude, tends to decrease with the MC internal angle decrease; compare the entrance 1 and entrance 4 results. But this trend is not followed by the pressure forces measured at the lower FC outlet ( Figure 14c,d), since the time-averaged value of such pressure forces initially grows, and finally, shows a small decrease. This evolution is mostly due to the FC outlet area variation generated when going from entrance 1 to entrance 4; then, the initial increase in the FC outlet area appearing between entrances 1 and 2 is slightly smaller between entrance 2 and entrance 3, becoming almost negligible between entrances 3 and 4. In fact, the pressure force decrease observed in entrance 4 (Figure 14c,d) is due to the time-averaged stagnation pressure decrease observed at the MC's lower converging wall (Figure 14a,b). The change tendency between entrances 3 and 4, can aldo be observed from the analysis of the mass flow forces acting on the lower FC outlet (Figure 14e,f). The time-averaged values of the mass flow forces at the lower FC outlet, as well as the peak-to-peak amplitude, keep growing from entrance 1 to entrance 3. This is mostly due to the FC mass flow increase, but also to the FC outlet area increase. The averaged value shows a negligible variation when moving from entrance 3 to entrance 4 and the peak-to-peak amplitude decreases. The peak-to-peak values are related to the maximum/minimum FC mass flow values presented in Figure 12c: the higher the peak values, the higher the mass flow force's amplitude. From the observation of Figure 14c,e, it is clear that the pressure forces on an FC outlet are over two orders of magnitude higher than the mass flow forces, which makes the jet oscillations particularly dependent on pressure variations. Figure 14g,h, introduce the overall resulting forces acting on the jet as it enters the MC, and are obtained from the addition of the net mass flow and pressure forces presented in Figure 13a,b. The peak-to-peak amplitude of these forces increases as the MC angle decreases. Note that although the time-averaged stagnation pressure at the MC's converging wall decreases when moving from entrance 2 to entrance 3 and entrance 4 (Figure 14b), the maximum overall forces on the jet keep increasing. Figure 8:0 All graphs consider the four mixing chamber angular modifications studied. 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 their respective average values and peak-to-peak amplitudes (**f**). Instantaneous net momentum obtained when considering pressure and mass flow momentum terms at both FC outlets (**g**), average values, and the peak-to-peak amplitudes (**h**).