|MLA Citation:||Bloomfield, Louis A. "Question 1117"|
How Everything Works 23 Apr 2018. 23 Apr 2018 <http://howeverythingworks.org/print1.php?QNum=1117>.
In the other view, the blades "fly" through the fluid like the wings of an airplane. The fluid flow around each blade is such that the pressure is higher on one side of the blade than the other and the blade experiences a net force toward the lower pressure side. The blades move in the direction of this force, so the passing fluid does work on them—energy is transferred from the fluid to the blades.
These two views are completely equivalent. The fluid leaves the turbine blades traveling more slowly or at lower pressure, and it acquires a rotation in the direction opposite the turbine's rotation.