**3. Performance Parameters**

Two performance parameters were defined to evaluate the performance of the fluidic oscillator depending on the bending angle. The first one is the peak velocity ratio of the oscillating jet at the exit of the fluidic oscillator (*FVR*), which is defined as follows:

$$F\_{VR} = \frac{\mathcal{U}\_{peak}}{\mathcal{U}\_{ref}} \tag{1}$$

where reference velocity *Uref* is the velocity at the outlet throat.

$$\mathcal{U}\_{ref} = \frac{\dot{m}\_{inlet}}{A\_{ref}\rho} \tag{2}$$

*Upeak* is the peak value of the time-averaged jet velocity at the oscillator outlet, . *minlet* is the mass flow rate at the inlet, *Aref* is the area of the outlet throat, and *ρ* is the air density at 25 ◦C.

The second performance parameter is the dimensionless pressure drop (*Ff*), which directly affects the pumping power:

$$F\_f = \frac{\Delta p D\_h}{2\rho L\_{ref}^2 S} \tag{3}$$

where Δ*p* is the pressure drop through the fluidic oscillator, *Dh* is the hydraulic diameter of the outlet throat, and S is the distance between the inlet and the outlet throat shown in Figure 1.

On the other hand, to evaluate the aerodynamic performance of the airfoil with fluidic oscillators, the lift and drag coefficients are defined as follows:

$$C\_L = \frac{L}{\frac{1}{2}\rho\_{\infty} \,\,\,\,\mathcal{U}\_{\infty}^2 \,\, c \,\, s} \tag{4}$$

$$C\_D = \frac{D}{\frac{1}{2}\rho\_{\infty} \,\,\mathcal{U}\_{\infty}^2 c \, s} \tag{5}$$

where *L*, *D*, *ρ*, *U*, *c*, and *s* indicate the lift force, drag force, fluid density, velocity, airfoil cord length, and width of the computational domain, respectively. The subscript ∞ indicates free-stream values.
