Measurement of energy losses in oscillatory flow through a pipe exit

A series of experiments is described in which energy losses are measured in a reversing oscillatory flow through a pipe exit. The experiments provide a comparative study of the losses associated with sinusoidal flow through exits of various shape, and in particular how the curvature of the exit determines the degree of flow loss due to the shedding of vortices. It is shown that geometrical factors relating the amplitude of motion to the curvature of the mouth and radius of the tube have an important bearing on the incidence of energy loss; significant losses are only observed to occur once a particular amplitude of motion is exceeded. In addition photographic visualization is used to provide evidence connecting the generation of eddies with increased losses.