A little bit about Venturis....
A venturi works by creating a low pressure areas and increasing velocity through the narrow point. Making this narrow point an ideal place for a turbine to harness hydro kinetic energy.
An example of a double ended venturi that did not make the cut.
The DHV Turbine difference !!
The DHV design creates low pressure inside the venturi so the path of least resistance is through the venturi.
Real world experiments
A decent increase in performance for a vertical axis darreus turbine.