## 5 Results
### Modifying the (Mc) Outlet Angle  
Figure 10 presents the results obtained when modifying the (MC) outlet angle and for the three Reynolds numbers evaluated. The (FO) output mass flow frequency and amplitude keeps decreasing as the inclination angle increases. The frequency effect is perfectly understandable once it is realized that the (MC) outlet converging walls, play a key role regarding the flow directed towards the (FC's) and the pressure waves transmission. Not only the position of the stagnation pressure point is modified by this angle but also its magnitude will be affected. The stagnation pressure maximum value as well as the peak to peak pressure amplitude, was observed to decrease with the (MC) angle increase. High frequencies are linked to high stagnation pressure values and vice versa. Furthermore, high (MC) outlet angles tend to direct the pressure waves towards the (FC) located opposite to the wall where the main jet impinges, the main flow stream is directed towards the (FO) outlet. On the other hand, small (MC) outlet angles, have associated a much wider area where stagnation pressure exists, maximum stagnation pressure values and peak to peak amplitudes are obtained under these conditions. Small angles direct the mass flow and specially the pressure waves towards the (FC) located next to the wall the main jet impinges, periodically pressurizing the (FC), compare Figure 11a,c with Figure 11b,d. This is the reason why, small (MC) outlet angles, have associated higher frequencies and amplitudes. The effect of the (MC) outlet angle on the (FO) outlet mass flow amplitude, can be further explained when taking into account that, higher angles tend to direct the main flow towards the (FO) outlet central horizontal axis, therefore tending to decrease the jet deflection. Notice from Figure 12 that the amplitude of all parameters is particularly small at high outlet angles. The flow leaves the (EC) rather tangentially to the wedge walls and across one of the outlets at a time, generating a large vortex on the opposite outlet of the (EC). For high (MC) outlet angles, the fluid velocity at the (FO) outlets, is rather uniform across one of the exits at a time and always leaves the oscillator, there is no reverse flow, see Figure 12a. As the angle decreases, the outlet maximum fluid velocity magnitude increases, for a given oscillation period and during approximately one third of the period, the mass flow in any of the two exits enters the oscillator, for the rest of the period the fluid leaves the oscillator at a relatively high speed, the peak to peak output mass flow amplitude is maximum under these conditions, see Figure 12a. Again we are observing that large (FO) output mass flow amplitudes, have associated reverse flow at the (FO) outlets. Figure 11 represents the oscillator overall velocity and pressure fields when the outlet angles are respectively the largest and smallest studied. From Figure 11b, which characterizes the smallest angle evaluated, it is noticed that the jet impinges nearly perpendicular to the (MC) lower converging wall, generating a large area where the stagnation pressure acts, see Figure 11d. The stagnation pressure and its peak to peak amplitude, reach their respective maximums under these conditions, see  
Figure 10: Frequency (**a**) and amplitude (**b**) of the (FO) outlet dynamic mass flow, as a function of the mixing chamber outlet angle and for three different Reynolds numbers, 8711, 16034 and 32068. Figure 12c. Pressure waves and some fluid flow are directed from the lower (FC) inlet to the outlet. the lower feedback channel is pressurized, Figure 11d.