## 5 Results
### Relation Reynolds Frequency for All Dimensional Modifications Performed
This comparison given as the ratio between the static pressure divided by the (FC) mass flow term, is presented in Table 7. There are four geometry modifications, highest inlet width, highest inlet angle, lowest outlet angle and lowest outlet width, at which the pressure/mass flow momentum ratio is particularly small, indicating that under these conditions, the feedback channel mass flow plays a more relevant role regarding the net momentum applied to the jet. Notice that these four geometry modifications, are the same ones generating a particular increase in the exponent associated to the Reynolds number, observed when comparing Tables 5 and 6. The conclusion is that, for these particular geometry modifications, the (FC) mass flow plays a more relevant role, although small, on the net momentum driving the oscillation. Yet, regardless of the geometry modification and the Reynolds number studied, the oscillation of the jet in the (MC) is mostly driven by the pressure difference at the (FC) outlets. Finally, and based on the results presented in Table 7 it can be concluded that, the pressure/mass flow momentum ratio is highly dependent on the geometry modification, but it is not particularly affected by the Reynolds number. Regarding the inlet width variations, from the results obtained it is observed that, the stagnation pressure and the net momentum peak to peak amplitudes, suffer a minor increase as the inlet width increases. When comparing the minimum and maximum inlet widths studied, at Reynolds number 16034, the peak to peak stagnation pressure and momentum increase, were respectively of 17% and 31% versus their minimum values. When considering the outlet width effects on the (MC) converging walls peak to peak stagnation pressure amplitude, it was observed that as the outlet width decreases, the peak to peak stagnation pressure amplitude keeps increasing, also the net momentum amplitude acting on the lateral surfaces of the (MC) incoming jet, increases as the outlet width decreases. When comparing the minimum and maximum outlet widths studied, the increase of the peak to peak stagnation pressure and momentum, at \(\text{Re}=16034\), was respectively of 39% and 36%. The same trend is observed under all Reynolds numbers studied. As Reynolds number increases, the variation in percentage for both parameters decreases. When evaluating the (MC) outlet angle and for all the cases studied, the minimum peak to peak (MC) converging walls stagnation pressure, was obtained when the highest outlet angle was employed. As the outlet angle decreased, the peak to peak stagnation pressure at the (MC) outlet converging walls, as well as the peak to peak momentum amplitude at the (FC) outlets, kept increasing. The increase versus the minimum value was respectively of 68% and 38% at \(\text{Re}=16034\). As Reynolds number grows, the variation in percentage reduces. When using the highest outlet angle, the peak to peak net momentum amplitude associated was higher than for the case where the lowest inlet width was used. The decrease of the inlet width, appears to particularly reduce the net momentum applied to the (MC) incoming jet. The mass flow along the (FC's) is effectively controlled by the inlet width. Regardless of the Reynolds number, as the inlet angle increases, the stagnation pressure peak to peak amplitude at the (MC) converging walls, also increases. The increase is more relevant at high Reynolds