**Figure 18.** *Cont*.

*Energies* **2020**, *13*, 5356

**Figure 18.** Air flow velocity distributions at an air velocity of 15.8 m/s around (**a**) the IceWind turbine and (**b**) the Savonius wind turbine.

**Figure 19.** *Cont*.

**Figure 19.** Air flow velocity streamlines at an air velocity of 15.8 m/s around (**a**) the IceWind turbine and (**b**) the Savonius wind turbine.

(**a**) (**b**)

**Figure 20.** *Cont*.

*Energies* **2020**, *13*, 5356

**Figure 20.** Pressure distributions at an air velocity of 15.8 m/s around (**a**) the IceWind turbine and (**b**) the Savonius wind turbine.

Figure 20a,b show air flow pressure distributions around the still IceWind and Savonius turbines' rotors. These results were obtained at the plane that goes through the bottom of the turbines' blades as both have the same complete shape at this plane. The concave side of the proceeding blade has a positive pressure, while the convex side of the same blade has a negative pressure. In contrast, the oncave side of the returning blade has a negative pressure, while the convex side of the same blade has a positive pressure. In other words, positive pressure appears on the turbine side facing the air, and the opposite sides have a negative pressure. At θ = 0◦, both figures show similar pressure distributions. The dead area is small, and the vortex producing a negative pressure almost disappears, whereas the largest dead area is observed in the wake of the returning blade at θ = 90◦. Separation

occurs due to an adverse pressure gradient in the downstream direction. Both figures show similar pressure distributions. Moreover, the maximum negative pressure appears at θ = 30◦ for both turbines.

Three-dimensional numerical modeling was successfully used in the current case to visualize the flow around both turbines. This visualization comparison with the Savonius turbine showed noticeably similar performances for the two turbines.
