Falah-Nezhad Taher

Grade: 
Graduated

The supercritical flow over vertical drops

Student Name

Taher Fallah-Nezhad

 

Supervisor

Mohammad Reza Chamani
(Assist. Prof._Civil Engineering Department_Isfahan University of Technology)

Mohammad Karim Beirami
(Assist. Prof._Civil Engineering Department_Isfahan University of Technology)

Date

1999

E-Mail

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Keywords

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Abstract

The present investigation is the first major contribution to the study of the supercritical flow over drops. Due to the similarity of the supercritical flow to the subcritical flow on drops, a basis for the analysis of flow characteristics was established. Flow parameters such as the relative energy loss, the downstream depth, the pool depth, and the pool length for various Froude number have been estimated. To compare the estimation of flow parameters with experimental results, the flow characteristics of the supercritical flow on drops were evaluated by the model study. Velocity profiles at the upstream and the downstream sections were measured with the Pitot static tube. Values of various depths have been also measured.

It was found that for a definite discharge, increasing the Froude number decreases the relative energy loss, the downstream depth, and the pool depth, but the pool length increases. For any given value of the Froude number and with increasing the discharge, the relative energy loss decreases, but the downstream depth, the pool depth, and the pool length increases. It was found that there are differences between predicted and experimental results for the relative energy loss and the downstream depth due to the entrainment of air at the downstream section which reduces the accuracy of the measurements. Similar differences for the pool depth and the pool length also exists because of the assumptions made in the proposed method. An empirical equation was derived to estimate the relative energy loss.

Since the proposed method can be executed for any Froude number, it can be used to predict flow characteristics of the subcritical flow on drops. There is a fair agreement between the experimental results obtained by earlier investigators and estimation of the proposed method.