## 5 Results
### Modifying the (Mc) Inlet Angle  
The flow effects caused by the modification of the (MC) inlet angle is presented in this section, just three angles including the baseline case, were considered, see Figure 13. It was observed that,  
Figure 12: Dynamic effects of the (MC) outlet angle modification on the main flow parameters, Reynolds number 16034. Each graph presents three non-dimensional curves characterizing results from the baseline, the lowest and highest outlet angle cases, and as a function of the dimensional time. In figure (**a**) the mass flow across the upper oscillator outlet is presented. Figure (**b**) introduces the temporal variation of the (MC) inlet inclination angle. Figures (**c**) presents the pressure at the (MC) lower inclined wall. The net momentum acting on the lateral sides of the main jet is presented in figure (**d**). Figure (**e**) characterizes the mass flow at the lower feedback channel outlet. the (FO) outlet mass flow peak to peak oscillation amplitude, when compared with the baseline case, increased an 8.9% for an inlet angle increase of 74%. When the inlet angle increased by 93%, the (FO) outlet mass flow amplitude increased versus the baseline case, just 1.6%. Regarding the (FO) outlet mass flow oscillating frequency, it increases very slightly with the inlet angle increase, in fact, as it has been introduced in all previous cases, the frequency and amplitude variations are more relevant as the Reynolds number increases. Figure 13 also clarifies that the same trend is observed regardless of the Reynolds number considered. Figure 14 introduces the velocity field and the pressure magnitude inside the (FO) for the maximum and minimum (MC) inlet angles evaluated. As the inlet angle increases, there is less space on both sides of the jet in the (MC) for the Coanda effect to appear, yet the jet keeps oscillating. This supports the thesis presented in this paper and already outlined in [12; 18], which established that in reality, what forces the jet to flip is the pressure term of the net momentum acting on the lateral sides of the jet entering the (MC). Regardless of the (MC) inlet inclination angle, the maximum stagnation pressure appearing at the (MC) converging walls is very similar, a peak to peak stagnation pressure increase of nearly 18% is observed when comparing the highest inlet angle evaluated with the lowest inlet angle case, compare Figure 14c with Figure 14d, see as well Figure 15c. As a result, the net momentum peak to peak amplitude acting onto the incoming jet lateral surfaces, suffers a small increase of 2.8%, although it is difficult to distinguish the different curves, this information is presented in Figure 15d. From the observation of Figures 4a,b, 8a,b, 11a,b and 14a,b, it is noticed that in all (FC's) 90 degrees corners small vortices appear, indicating it exists fluid recirculation in all these points. To minimize fluid recirculation it would be desirable to round all 90 degrees corners, the expected effect would be, a small increase of actuator frequency, since in reality rounding the corners would facilitate the fluid to move back and forward along the feedback channels, pressure losses would as well decrease, This observation was previously done by [5]. Figure 13: Fluidic oscillator output mass flow Frequency (**a**) and amplitude (**b**) as a function of the mixing chamber inlet angle and for three different Reynolds numbers, 8711, 16034 and 32068. Based on the results obtained in the present section, see Figure 15, it can be concluded that the effect of modifying the (MC) inlet angle, does not generate very relevant changes on any of the studied fluid flow parameters. In fact, the (MC) inlet angle seems to be particularly linked with the Coanda effect alternatively appearing on both sides of the mixing chamber. Yet, and based on the results obtained in the present set of simulations, the Coanda effect has a minor effect on the (FO) flow dynamic performance.