Purpose:
* To demonstrate the characteristics of flow over weirs.
* To determine the 'Coefficient of Discharge' for each type of weir.

Introduction:
In open channel hydraulics, weirs are commonly used to either regulate or to measure the volumetric flow rate. They are of particular use in large scale situations such as irrigation schemes, canals and rivers. For small scale applications, weirs are often referred to as notches and invariably are sharp edged and manufactured from thin plate material.

Apparatus:
Hydraulics Bench incorporates a weir channel. The rectangular notch weir or (V) vee notch weir to be tested is clamped to the weir carrier in the channel by thumb nuts. 4

2

5

8

7

6

3
1

Figure 1: Flow over Weirs - Figure 2: Flow over Weirs -
vee notch weir rectangular notch weir
1
5

2
6
Hydraulics BenchBasket of glass spheres
3
Weir channelVolumetric measuring tank
4
(V) Vee notch weir7
Rectangular weir
Hook & point gauge Hook Gauge and Scale8

There are different shapes of weirs that can be used to measure the volumetric flow rate. These shapes with their dimension are shown in fig 3 below.

Figure 3: Details of weirs

Theory:
* Rectangular Weir:
A rectangular notch is a thin square edged weir plate installed in a weir channel as shown in figure 4.

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Figure 4: Rectangular Notch
Consider the flow in an element of height δh at a depth h below the surface. Assuming that the flow is everywhere normal to the plane of the weir and that the free surface remains horizontal up to the plane of the weir, then velocity through element 2gh

∴ Theoretical discharge through element dQ=v.dA= 2gh.b.dh Integrating between h = 0 and h = H
Total theoretical discharge Qth=0H2gh.B.dh=B2g0Hh12.dh
So, Qth=23B2gH32
In practice the flow through the notch will not be parallel and therefore will not be normal to the plane of the weir. The free...

...Abstract
The objective of this experiment is to measure the force generated by impact of the jet on vanes of various shapes like flat plate, conical cup and hemispherical cup. Besides that, the results from the experiment have to be compared with the theoretical calculations too.
1.0 Introduction
Water turbines are widely used throughout the world to generate power. By allowing fluid under pressure to strike the vanes of a turbine wheel, mechanical work can be produced. Rotational motion is then produced by the force generated as the jet strikes the vanes. One way of producing mechanical work from fluid under pressure is to use the pressure to accelerate the fluid to a high velocity in a jet. The jet is directed on to the vanes of a turbine wheel, which is rotated by the force generated in the vanes due to the momentum change or impulse which takes place as the jet strikes the vanes. Water turbines working on this impulse principle have been constructed with outputs of the order of 100,000 kW and with efficiencies greater than 90%. In this experiment, the force generated by a jet of water as it strikes a flat plate, conical plate and hemispherical cup may be measured and compared with the momentum flow rate in the jet.
2.0 Experimental Design
2.1 Apparatus and Materials
The jetimpact apparatus
Volumetric...

...kkkkkkkkk
CVEN-3313 Theoretical Fluid Mechanics
MODULE#4 : Application of Impact on a Jet
1. OBJECTIVE
To use the momentum equation to estimate the force exerted by a jet on a stationary target.
2. THEORY
The momentum equation in the vertical (z) direction can be written as:
Applying the momentum equation for a control volume including the forces acting on a flat target or hemispherical target gives:
(1a : flat)
(1b : hemi)
It is assumed that the velocity going out of the control volume is equal to the velocity coming in. Additionally, the elevation difference within the control is assumed to be negligible. The vertical force caused by the jet is balanced by the mass placed on the weight pan.
(2)
The initial velocity of the jet, v0, is :
(3)
From Bernoulli’s equation, the jet velocity, v, in the control volume at the target is :
(4)
Combining equations (1) through (4), the following equations can be obtained for the flat and hemispherical targets, respectively.
(5a : flat)
(5b : hemi)
3. PROCEDURE
1) Install the flat target in the...

...Impact of A Jet
Philip Mah Koon Yue
Mohananda a/l Anantha Krishnan
Ahmad Saeed Abood
Eleanor Hang Lee Shean
Chan Jun Hoe
School of Engineering
Taylor’s University
Malaysia
23 March 2011
Table of Content
Abstract
3
1. Introduction
3
2. Experiment Design
3
2.1 Materials
3
2.2 Methods & Procedures
4
3. Results and discussion
5
4. Conclusion and Recommendations
8
References
8
Appendix
9
Abstract
The experiment was conducted to find the impact of water on different types of vanes, it consists of 3 types the flat plate, conical cup and the hemispherical cup. Forces are generated by jet of water impacts the vanes that produces various angles of deflection. In the end the slope calculated was used to compare with the theoretical slope and the deviation slope was calculated.
1.0 Introduction
One of the ways of producing mechanical work from fluid under pressure is to use the pressure to accelerate the fluid at high velocity in a jet. The jet is directed on the vanes of a turbine wheel, which is rotated by the force generated on the vanes due to the momentum change or impulse which takes place as the jet strikes the vanes. Water turbines working on this impulse principle have been constructed with outputs of the order of 100,000 kW and with efficiencies greater than 90%.
There are mainly two objectives...

...ABSTRACT
The purpose of the impact of jet experiment is to design a system to determine the force generated by the impact of jet on a variety of target vanes. A formula is given to calculate the reaction force at the different vanes caused by the jet. At the end of the experiment, the data collected and results calculated will then be compared to theoretical values which are given. Students are expected to be able to come to a conclusion regarding the relationship between the reaction force produced at the target vanes and the angle where the shape of the vanes curve.
1.1 INTRODUCTION
There are many ways to produce mechanical work from fluid under pressure. One of the famous ways is to use the pressure to accelerate the fluid to a high velocity in a jet. Over the years, engineers have found many ways to utilize the force that can be produced by a jet of fluid on a surface diverting the flow. For example, the pelton wheel has been used to make flour. Firemen make use of the kinetic energy stored in a jet to deliver water above the level in the nozzle to extinguish fires in tall buildings. Fluid jets are also used in industry for cutting metals and debarring. This goes to show the importance of applications of the fluid jet in the technological aspects of various fields in our society.
This experiment aims at...

...IMPACT OF A JET
OBJECTIVES:
To measure the force generated by impact of the jet on vanes of various shapes.
To compare the results from the experiment with the theoretical calculations.
APPARATUS:
The JetImpact Apparatus
Volumetric Hydraulic Bench/Water
3 different shapes of vanes; Flat Plate, Conical Cup, and Hemispherical Cup
Stop Watch
1. INTRODUCTION
One way of producing mechanical work from fluid under pressure is to use the pressure
to accelerate the fluid to a high velocity in a jet. The jet is directed on to the vanes of a
turbine wheel, which is rotated by the force generated on the vanes due to the momentum
change or impulse which takes place as the jet strikes the vanes. Water turbines working
on this impulse principle have been constructed with outputs of the order of 100,000 kW
and with efficiencies greater than 90%.
In this experiment, the force generated by a jet of water as it strikes a flat plate, conical
plate, and hemispherical cup may be measured and compared with the momentum flow
rate in the jet.
2. DESCRIPTION OF APPARATUS
The JetImpact Apparatus, H8, has been designed for use with the Hydraulic Bench, H1.
This provides the necessary water supply and flow measurement facility. Figure 1 shows
the arrangement in which the bench supply is led to...

...
IMPACT OF a jet
ABSTRACT
The objective of this experiment is to determine the force exerted by a jet of water on vanes of various shape.Three different shape of vanes;flat plate,conical cup,and hemispherical cup are used for this experiment.The results obtain from the experiment are then used to compare with the theoretical results.Force generated on the surface of vane depends on the rate of change of momentum and it can be calculated by recording the time taken for water to reach a certain height and also the displacement of a jockey weight above apparatus.As a conclusion,the angle of the jet on the vane is directly proportional to the force produced.
1.0 INTRODUCTION
The aim of this experiment is to determine the force generated by the impact of the water jets on different shapes of vanes, which would be flat surface , conical cup and hemisphere cup and also how does the force related to the momentum flow rate in the jet. We will measure the velocity changed during hitting the vanes of various shapes and the force generated will be compared with the momentum changed.
Water turbine is a water-based power generating system operate by converting the impact of water jet into torque power of turbine to generate electrical power. One or more water jets, normally under pressure , are directed tangentially to the buckets...

...
IMPACT OF A JET
Introduction
Water turbines are widely used throughout the world to generate power. In the type of
water turbine referred to as a Pelton† wheel, one or more water jets are directed
tangentially on to vanes or buckets that are fastened to the rim of the turbine disc. The
impact of the water on the vanes generates a torque on the wheel, causing it to rotate
and to develop power. Although the concept is essentially simple, such turbines can
generate considerable output at high efficiency. Powers in excess of 100 MW, and
hydraulic efficiencies greater than 95%, are not uncommon. It may be noted that the
Pelton wheel is best suited to conditions where the available head of water is great,
and the flow rate is comparatively small. For example, with a head of 100 m and a
flow rate of 1 m3/s, a Pelton wheel running at some 250 rev/min could be used to
develop about 900 kW. The same water power would be available if the head were
only 10 m and the flow were 10m3/s, but a different type of turbine would then be
needed.
To predict the output of a Pelton wheel, and to determine its optimum rotational
speed, we need to understand how the deflection of the jet generates a force on the
buckets, and how the force is related to the rate of momentum flow in the jet. In this
experiment, we measure the force generated by a jet of water striking a flat plate...

...EG-125 Civil Labs II
ALEXANDRA T. STANLEY 647341
Main Report: Impact of a Jet
Team: B Evans 640786
T Denham 636120
J Cheetham 650261
J Davies 622673
Impact of a Jet
Introduction:
* The force produced and measured by this experiment can be used to produce energy in hydroelectric turbines.
* The aims in this experiment were to:
* Determine the force applied by the jet to the plate
* Compare the experimental result to the theoretical values, showing that the force exerted on the plate by the jet is equal to the rate of change of momentum in the jet.
Theory:
-theoretical: Normal force on the plate (Fx)=ρQV1 where ρ=density, Q=flow, V1=the x component of velocity of the fluid.
-experimental: force due to the jet= xw/L where L=0.151m and w=0.5kg
Procedure: -adjust the weight to set distance(see results table)
-open the valve so that the force provided by the jet causes equilibrium in the system.
-record the time taken for 0.006m3 of water to collect in the tank.
-from this determine the flow rate (volume/time)
-use the formulae mentioned in the theory section to determine the experimental and theoretical values for the force.
-repeat these stages for at least 4 more values of x (spacing 2cm between readings recommended).
Results:
Conclusion: the experimental results are not far...