I'm trying to design a quasi-simple vertical axis wind turbine, and a coworker came up with this design to focus the wind as it reaches the turbine in a wind tunnel. He says that there's going to be turbulence caused by some of the design factors, but I'm not quite sure why and he doesn't know why, either. Why, and where, would this design cause turbulence, and what improvements could be made to improve it?
The diagram is not labeled, but if the green lines are rigid walls I can see that the wind is given angular momentum by the shape. Angular momentum is conserved and will create turbulence in a fluid.