Experimental study for effect manning roughness on Froude number in open channel flow

Dissertant

al-Najjar, Fadiyah Faruq Khayri

Thesis advisor

al-Adili, Aqil Shakir
al-Sadi, Ali S.

University

University of Technology

Faculty

-

Department

Department of Building and Construction Engineering

University Country

Iraq

Degree

Master

Degree Date

2013

English Abstract

The friction factor of an open channel flow is generally affected by the characteristics of the fluid such as flow, geometrical section and the properties of the channel boundary layer.

Knowing of flow resistance in channels is necessary for many purposes such as the estimation of stage-discharge relationship, and the evaluation of sediment transport from the hydraulic characteristics of the channel by means of transport formulas.

All relationships between Froude number and Manning's roughness coefficient lead to obtain useful information in design, implementation, minimization the construction cost, and design the economical section.

The goal of the present work is to investigate (experimentally) experimental study for effect Manning roughness on Froude number in open channel flow, as well as, to establish some relations between different parameters, like Froude number with Manning’s Roughness coefficient (n), velocity and head, in order to find useful relations.

Three different cases have been adopted in this study to find out the relation between Fr and n.

The first one is experimental tests on open channel laboratory flume, the second is to predict relationships from the concrete lining irrigation canal, and the two procedure conducted in a selected reach of a natural stream Main Outfall Drain P^ect (M.O.D) as a case study located between regions Mahmudiyah, and J'bala.

From a three sections within this reach the relations have been extracted to indicate the correlation between Fr and n from upstream in Mahmudiyah region to downstream in J'bala region.

Also, a programming and statistical relationships (multiple regressions) was used to analyze the results.

In the experimental tests on open channel laboratory flume, the relationship between Froude number and Manning’s roughness coefficient n gave a good relationship and a good agreement with the observed values.

Also, the results showed that the values of Manning’s roughness coefficient in the channel sides are greater than the values of Manning’s roughness coefficient in the middle of channel, which decreases toward the channel sides and bottom direction.

In the second case the lined irrigation canal, the relationship between Froude number and Manning’s roughness coefficient n appears as a polynomial relation of the fourth degree and a moderate relationship between of them.

In the third case, natural stream river Main Outfall Drain (M.O.D), the relationship between Froude number and Manning’s roughness coefficient n gave a good relationship in the two regions.

As well as, the relationship between Froude number and Manning’s roughness coefficient n gave a good relationship in these two regions especially at Mahmudiyah region and a good agreement with the observed value.

This study could reveal and obtain a general equation that can correlate the Froude number with friction factor (n) in three cases together.

Main Subjects

Engineering & Technology Sciences (Multidisciplinary)

Topics

• Hydraulic engineering
• Fluid mechanics
• Water
• Distribution(Economic theory)

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-417664