Tesla turbine

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The Tesla turbine, patented by Nikola Tesla in 1913, is a bladeless centripetal flow device that functions via the boundary layer effect. Unlike conventional turbines, it does not rely on fluid impinging upon blades; rather, it's also known as a cohesion-type or Prandtl layer turbine (named after Ludwig Prandtl). Researchers in bioengineering refer to this technology as a multiple disk centrifugal pump. Tesla envisioned its application for geothermal power, as documented in "Our Future Motive Power."