|Nikola Tesla fluid dynamics|
Referred to as a bladeless turbine, the Tesla turbine isn’t really bladeless, but has many smooth disks that lie along the line of flow and not athwart it. The surface layer of the moving fluid spins the disks by adherence according to what is called the boundary-layer effect.
Disks in the Tesla turbine are smooth. Without vanes to be torqued by the flow, they are more sturdy. But the need for the disks to be thin to reduce warping from turbulence at the edges of the disks was a challenge.
In practice, Testla turbines were less efficient than conventional turbines. But if you power the Tesla turbine, it becomes a pump which, owing to its lack of vanes, can be used to pump waste materials that contain solids that would block a normal pump.