The study of the effect of gravity on nozzle flows by hodograph transformation

The effect of gravity on incompressible potential nozzle flows was studied by the method of hodograph transformation coupled with numerical computations. It is learned that the method of hodograph transformation can be successfully applied to problems involving curved channel walls. Calculations were performed for flows discharging from nozzles of different geometries. Results show that the effect of gravity cannot be underestimated before it is fully assessed. One dimensional approximation can also lead to erroneous results. The important information of the variation of the total head (or far upstream pressure) with volumetric discharge rate for different nozzles was obtained. It is also learned that early flow separation along the top channel boundary can occur when the total flow mechanical energy is too small. Thus various flow regimes of gravitational nozzle flows are classified and discussed.