Incipient Jump Condition for Ventilated Sill Flow
Publication: Journal of Hydraulic Engineering
Volume 112, Issue 10
Abstract
The incipient jump condition over continuous, rectangular sills is analyzed for fully ventilated flow at the rear side of a sill. The condition examined corresponds to the limiting sill height, for which the surface profile still remains continuous and the flow is thoroughly supercritical. Slightly augmenting the sill height for fixed approaching conditions results in a local surface discontinuity, e.g. the incipient configuration of a hydraulic jump controlled by the sill. The drag coefficient of the sill is determined using the gravity‐free Réthy solution. Application of the longitudinal momentum theorem then allows predicting the limiting relative sill height for gravity flow in terms of the approaching Froude number, provided critical flow is assumed at the maximum water rise. The result is compared with observations collected in two rectangular channels, the first having a drop after the sill, while the sill is mounted on a horizontal bottom in the second channel. It is found that both configurations follow the same main trend and agree fairly well with the prediction.
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Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 112 • Issue 10 • October 1986
Pages: 953 - 963
Copyright
Copyright © 1986 ASCE.
History
Published online: Oct 1, 1986
Published in print: Oct 1986
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