On the Flow in the Gradually Contracted Open Channel (II)

Experimental results

Abstract

This report concerns the experiments to verify the characteristics of the gradually contracted open channel theoretically obtained in last report.
In these experiments, it was verified that there are two types of contraction, i. e.η=βξ and η>βξ and varies together with η in the former type and η alone varies atξ=1 in the latter. Then n, the exponent of the power law of a velocity distribution profile, varies with contractions of cross section. The variation of n with weir contraction differs from that in with side wall contraction. The variation of n with weir contraction is shown by the experimental equation n=1/7Ar^1.775
It has been confirmed by the experiments that the uniformity of the velocity profile at the throat or crest appears more rapidly in side wall contraction than in weir contraction under the same variation of cross section. And then, the uniformity of velocity profile at the crest in weir contraction depends on the decrease of η and n, but the profile is effected more largely by n rather than by η
The velocity profiles obtained by experiments agree with calculated results. This may be applied to the design of the rapid acceleration divider