Summary of Contents for Armfield C4-MKII
- Page 1 An ISO 9001 Company INSTRUCTION MANUAL C4-MKII ISSUE 7 SEPTEMBER 2006 MULTI-PURPOSE TEACHING FLUME...
- Page 3 If requested then Armfield can supply a typical set of standard laboratory safety rules, but these are guidelines only and should be modified as required. Supervision of users should be provided whenever appropriate.
- Page 4 Moving or Rotating Components The C4-MKII Multi Purpose Teaching Flume has moving components. • Before operating the jacking system ensure that no person or object can become trapped by the movement of the flume or the jacking mechanism. The C4-67 Wave Generator has moving and rotating components.
- Page 5 Water Borne Hazards The equipment described in this instruction manual involves the use of water, which under certain conditions can create a health hazard due to infection by harmful micro-organisms. For example, the microscopic bacterium called Legionella pneumophila will feed on any scale, rust, algae or sludge in water and will breed rapidly if the temperature of water is between 20 and 45°C.
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Page 6: Table Of Contents
MULTI-PURPOSE TEACHING FLUME C4-MKII Contents Introduction to the Equipment ......................... 7 Diagram 1: Inlet End of Flume ........................8 Diagram 2: Discharge End of Flume......................9 Description................................ 10 Overview ..............................10 Working Section ............................10 Inlet Tank ..............................10 Overshot Weir ............................10 Optional Flowmeter .......................... - Page 7 Flow Rate ..............................22 Electrical Supply ............................23 Water Supply and Drain...........................23 Hook and Point Gauges (2 supplied) .......................23 Models Available for Use in the C4-MkII Flume ..................23 Routine Maintenance............................25 General..............................25 RCD test for F1-10 Hydraulics Bench .....................25 Test condition of water in F1-10 Hydraulics Bench.................25 Check C4-MkII for leaks ..........................25...
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Page 9: Introduction To The Equipment
The C4-MkII flume is supplied with either a 2.5 metre long working section or a 5.0 metre long working section. Both versions of the flume can be fitted with an optional direct reading flowmeter for convenience in operation. -
Page 10: Diagram 1: Inlet End Of Flume
Diagram 1: Inlet End of Flume... -
Page 11: Diagram 2: Discharge End Of Flume
Diagram 2: Discharge End of Flume... -
Page 12: Description
The frame is supported on pedestals, and a jack allows the flume to be tilted. The flume is designed to be used with an Armfield F1-10 Hydraulics Bench, which provides a re-circulating water supply and a volumetric measuring facility. -
Page 13: Hook And Point Gauges
0% (bed of channel level). The F1-10 Hydraulics Bench The C4-MkII is designed for use with the F1-10 Hydraulics Bench. The F1-10 is not supplied as part of C4-MkII. Water is drawn from a sump tank in the base of the F1-10 by a centrifugal pump. The water is delivered to the inlet tank of the flume via a flexible tube that is connected to the outlet in the moulded channel on the top of the F1-10. - Page 14 At higher flowrate (above 1.2 litres/sec) it will be necessary to use the circular orifice plate supplied with the C4-MkII to measure the flowrate as the volumetric tank will remain flooded. To install the orifice plate lift the ball and weight from the aperture in the base of the volumetric tank then press the orifice plate into the aperture.
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Page 15: Operation
Screw the adaptor, supplied with C4-MkII, onto the threaded outlet in the bed of the channel then connect the flexible tube from the C4-MkII to the union on top of the adaptor. The union incorporates a ‘O’ ring seal and only needs to be hand tight (do not use a tool to tighten the fitting). -
Page 16: Filling The F1-10 Hydraulics Bench With Water
Filling the F1-10 Hydraulics Bench with water Place a filling hose in the volumetric tank of the F1-10. Fill the sump tank with clean cold water by lifting the dump valve in the base of the volumetric measuring tank and allowing the water to drain from the volumetric tank into the sump tank. -
Page 17: Assembling And Installing The Venturi Flume
When not in use the model clamping rods can be inverted to minimise disturbance to the flow along the bed of the channel. To invert the rod unscrew the gland on the underside of the bed then pull the rod out from the gland from above. Re-insert the rod into the gland from below (taking care not to damage the ‘O’... -
Page 18: Installing The Optional Roughened Bed Sections
Installing the Optional Roughened Bed Sections The artificially roughened (gravel) bed relies on its own weight to hold it onto the channel bed. It is aided by a bed end stop which is similar to the stretcher screw used on the Venturi flume except that it clamps between the channel side walls. -
Page 19: Installing The Optional Pitot Tube And Manometer Board (C4-61)
3.10 Installing the Optional Pitot Tube and Manometer Board (C4-61) The Pitot tube and manometer board is an optional accessory (Armfield order code C4-61) and is used in conjunction with the C4-MkII Multi Purpose Teaching Flume to measure the local velocity of water flowing through the working section. -
Page 20: Operating The Optional Pitot Tube And Manometer (C4-61)
Allow water to drain from the reservoir leaving a small amount in the base, then close the isolating valves at the base of the manometer. Fill the reservoir with paraffin (Kerosene, Specific Gravity = 0.784) then open each isolating valve in turn to half fill each manometer tube with paraffin. - Page 21 For defining the position of the Pitot tube relative to the flume the following convention is used: = distance along the flume (scale on side of flume) = location across flume = height above bed of flume (vertical level gauge) These dimensions can be tabulated with the other results obtained.
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Page 22: Installing The Optional Wave Generator (C4-67)
3.12 Installing the Optional Wave Generator (C4-67) When required for use, the C4-67 Wave Generator should be mounted on top of the flow channel inlet tank with the vertical paddle at the entrance to the working section. The Wave Generator must be secured to the flange of the tank using the fixings supplied. - Page 23 The connecting rod can be attached to the crank wheel at different radii to give different stroke lengths. To change the stroke length simply unscrew the pin that attaches the connecting rod to the crank wheel using a suitable wrench then screw the pin into the appropriate tapped hole. Ensure that the pin securing the connecting rod is tight using a wrench.
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Page 24: Specifications
Overall Dimensions C4-MKII-2.5M only Height 1.50m Length 3.4m Width 0.62m C4-MKII-5.0M only Height 1.50m Length 5.41m Width 0.62m C4-MKII-2.5M with F1-10 Height 1.50m Length 3.66m Width 0.90m C4-MKII-5.0M with F1-10 Height 1.50m Length 6.11 m Width 0.90 m Working Section Dimensions Length of working section 2.5m or 5.0m (as ordered) -
Page 25: Electrical Supply
(supplied with the hydraulics bench) for details. Water Supply and Drain Water for the C4-MkII is provided by an F1-10 Hydraulics Bench. An initial fill of approximately 250 litres is required. Once the equipment has been installed and commissioned no permanent water supply or drain is required. - Page 26 C4-68 False floor sections for gradually varied profiles, comprising: variable height laminated ramp, 2 parallel face sections with 2 end ramps and support piece to create raised false floor using 1 parallel face section C4-69 Artificially roughened bed 2.5m long section (2 required for 5.0m flume).
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Page 27: Routine Maintenance
Switch on the pump with the flow control valve closed, then gradually open the valve to circulate the water through the C4-MkII channel and F1-10 to ensure that the inhibitor has dispersed thoroughly and coated all wetted surfaces with a protective film. -
Page 28: Check Condition Of Channel Bed
Check condition of channel bed The surface of the aluminium bed inside the channel section is treated with chlorinated rubber paint (Oxford Blue BS105) to provide corrosion resistance. It is important that this finish is maintained in perfect condition to prevent corrosion of the bed. Inspect the bed thoroughly for any sign of damage to, or deterioration of, the paint finish, such as scratches, discoloration, peeling, blistering etc. - Page 29 5.6.3 Repainting the Channel Bed If repainting is necessary the following steps should be carried out: All existing paint on the bed should be completely removed and the surface degreased prior to painting. The surface of the bed and the joints between the clear acrylic side walls and the bed must be fully dry prior to painting.
- Page 30 by the walls and the bed. Although leakage may not be evident, check the seal between the clear acrylic panels and the bed of the channel. Apply silicone sealant to the corner of the joint if any doubt exists. All PVC and rubber hoses/sleeves must be checked and replaced if perished. Despite appearing leak-tight, all joints should be checked for integrity and re-seated if necessary.
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Page 31: Laboratory Teaching Exercises
6 Laboratory Teaching Exercises Index to Exercises General Nomenclature ..............................30 Nomenclature for Free Surface Flow........................31 Exercise A: Characteristics of Flow over a Sharp Crested Overshot Weir............32 Exercise B: Characteristics of Flow over a Broad Crested Weir ................36 Exercise C: Characteristics of Flow over a Crump Weir..................40 Exercise D: Discharge Beneath a Sluice Gate ......................44 Exercise E: Force on a Sluice Gate ..........................48 Exercise F: Derivation of the Specific Energy Equation..................52... -
Page 32: General Nomenclature
General Nomenclature Name Symbol Units Definition Breadth of channel/weir etc Measured Gravitational constant 9.81m s Difference in manometer readings Calculated from manometer readings Volumetric flowrate Measured or calculated Hydraulic mean radius Temperature of water Measured °C Local fluid velocity Mean fluid velocity Depth of fluid at any location Measured Density of fluid... -
Page 33: Nomenclature For Free Surface Flow
Nomenclature for Free Surface Flow Name Symbol Units Definition Velocity of gravity wave in still (sometimes called shallow water celerity) Coefficient of contraction Coefficient of discharge Coefficient of velocity 0.95<C <1.0 Specific energy head (total energy E = y + V /2g Note : If head measured relative to channel the datum is the channel... -
Page 34: Exercise A: Sharp Crested Overshot Weir
To calculate the discharge coefficient and to observe the flow patterns obtained. Method By using the Sharp Crested weir installed in the C4-MkII flume and comparing the flow characteristics under a range of flow conditions with the aeration pipe open and with the aeration pipe closed. - Page 35 Theory For a rectangular sharp crested weir: therefore: where: = Volume flowrate = Volume/time (using volumetric tank) = Coefficient of discharge (Dimensionless) = Breadth of weir = Height above crest of weir (upstream) = Gravitational constant (9.81ms = Height of weir crest above bed = Upstream flow depth When the rectangular weir extends across the whole width of the channel it is called a suppressed weir and the Rehbock formula can be applied to determine C...
- Page 36 Equipment Set Up Ensure the flume is level, with no stop logs installed at the discharge end of the channel. Measure and record the actual breadth b (m) of the sharp crested overshot weir (rectangular weir). Install the weir in the flume with the sharp edge upstream. Ensure that the weir is secured using a mounting hook through the bed of the flume.
- Page 37 Results Tabulate your measurements and calculations as follows: Breadth of Weir b =…………(m) Height of weir h =…………(m) log y log Q Plot Q against y , log Q against log y and C against y From the straight-line graph of log Q against log h find the intercept log k on the log Q axis and the gradient m.
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Page 38: Exercise B: Broad Crested Weir
Broad Crested weir (long base weir). To calculate the discharge coefficient and to observe the flow patterns obtained. Method By using the Broad Crested weir installed in the C4-MkII flume and operating the flume under a range of flow conditions. Equipment Required... - Page 39 Theory From conservation of energy and ignoring losses: Therefore − The flow rate Q is given by: − Provided that the weir is not submerged (downstream water level is low), the flow over a Broad Crested Weir may be assumed to be critical as it passes over the weir. Hence –...
- Page 40 where C is the coefficient of discharge. actual i.e. actual theoretical The Coefficient of Discharge may therefore be determined as Actual Flow Rate Theoretica Flow Rate Equipment Set Up Ensure the flume is level, with no stop logs installed at the discharge end of the channel. Measure and record the actual breadth b (m) of the broad crested weir.
- Page 41 Results Tabulate your readings and calculations as follows: Breadth of Weir =…………(m) Height of weir =…………(m) actual theoretical Plot graphs of Q against H and C against H actual Conclusion Does the magnitude of the flowrate affect the discharge coefficient C ? Does C increase or decrease with increasing flowrate?
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Page 42: Exercise C: Crump Weir
Crump weir. To determine the modular limit and to observe the flow patterns obtained. Method By using the Crump weir installed in the C4-MkII flume and operating the flume under a range of flow conditions. Equipment Required Armfield C4-MkII Flume... - Page 43 Theory For Modular Flow (weir operates undrowned, downstream water level low) therefore: where: = Modular volume flowrate = Volume/time (using volumetric tank) = Breadth of weir = Gravitational constant (9.81ms = Total head upstream of weir crest = Upstream depth of flow above weir = Upstream flow rate = Q for modular flow (m³/s)
- Page 44 For Non-Modular Flow (weir crest drowned, downstream water level high) The weir ceases to act in modular fashion when: ≥ where: = Total head downstream of weir crest = downstream flow rate = Total head upstream of weir crest = upstream flow rate When the flow is not modular the upstream head is affected by changes in the downstream head.
- Page 45 Procedure Open the flow control valve and allow the water to flow into the flume then adjust the valve to obtain a depth y of 0.070m upstream of the weir. Maintain this level whilst measuring the downstream depth of flow y and the flowrate Q.
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Page 46: Exercise D: Discharge Beneath A Sluice Gate
(undershot weir). To calculate the discharge coefficient and to observe the flow patterns obtained. Method By using the adjustable undershot weir installed in the C4-MkII flume and operating the flume under a range of flow conditions. Equipment Required... - Page 47 Theory For flow beneath a sharp edged undershot weir it can be shown that; therefore: where: = Volume flowrate = Volume/time (using volumetric tank) = Discharge coefficient (Dimensionless) = Breadth of weir = Height of weir opening above bed = Upstream depth of flow = Gravitational constant (9.81m s where:...
- Page 48 Equipment Set Up Ensure the flume is level, with no stop logs installed at the discharge end of the channel. Measure and record the actual breadth b (m) of the undershot weir. Clamp the undershot weir assembly securely to the sides of the channel at a position approximately mid way along the flume with the sharp edge on the bottom of the weir facing upstream.
- Page 49 Results Tabulate your readings and calculations as follows: Breadth of weir, b = ……………..(m). Plot graphs of Q against y for constant y and y against y for constant Q to show the characteristics of flow beneath the weir. Plot graphs of C against Q for constant y and C against y...
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Page 50: Exercise E: Force On A Sluice Gate
To determine the relationship between upstream head and thrust on a sluice gate (undershot weir) for water flowing under the sluice gate. Method By using the adjustable undershot weir installed in the C4-MkII flume. Equipment Required Armfield C4-MkII Flume Adjustable Undershot Weir model... - Page 51 Theory It can be shown that the resultant force on the gate is given by the equation: ρ ρ − − − The gate thrust for a hydrostatic pressure distribution is given by the equation: ρ...
- Page 52 Equipment Set Up Note : To save time, the measurements obtained in experiment D can be used to perform the calculations in this experiment. If results are not available proceed as follows: Ensure the flume is level, with no stop logs installed at the discharge end of the channel. Measure and record the actual breadth b (m) of the undershot weir.
- Page 53 Results Tabulate your readings and calculations as follows: Breadth of Weir, b = ……………..(m). Plot a graph of the ratio against the ratio Conclusion Compare your calculated values for F and F and comment on any differences. What is the effect of flow rate on the results obtained? Comment on the graph obtained.
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Page 54: Exercise F: The Specific Energy Equation
Objective To determine the relationship between the specific energy and upstream head for water flowing under an undershot weir. Method By using the adjustable undershot weir installed in the C4-MkII flume. Equipment Required Armfield C4-MkII Flume Adjustable Undershot Weir model... - Page 55 Theory The depth and velocity of a given flow at any section of an open channel adapt themselves to the energy available at that section. For a constant discharge this energy reaches a minimum value at the ‘critical’ depth. This parameter is fundamental to a complete understanding of free flow behaviour because the response of a stream to energy (and force) depends on whether the actual depth is greater than or less than the critical depth.
- Page 56 Considering unit width of channel the equation becomes: where: = Specific energy = Depth of flow = Volume flowrate = Volume/time (using volumetric tank) = Gravitational constant Note: When the datum coincides with the bed E = H A plot of specific energy against depth of flow gives a curve called the specific energy curve shown below.
- Page 57 Equipment Set Up Ensure the flume is level, with no stop logs installed at the discharge end of the channel. Clamp the undershot weir assembly securely to the sides of the channel at a position approximately mid way along the flume with the sharp edge on the bottom of the gate facing upstream.
- Page 58 Results Tabulate your readings and calculations as follows: Calculate E and E for each value of Q. Plot E against y and E against y to establish the shape of the curve on either side of the minimum energy point. Plot your calculated values for E on the same axes.
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Page 59: Exercise G: The Hydraulic Jump
To investigate the characteristics of a standing wave (the hydraulic jump) produced when water flows beneath an undershot weir and to observe the flow patterns obtained. Method By using the adjustable undershot weir installed in the C4-MkII flume. Equipment Required Armfield C4-MkII Flume... - Page 60 Theory When water flowing rapidly changes to slower tranquil flow a hydraulic jump or standing wave is produced. This phenomenon can be seen where water shooting under a sluice gate mixes with deeper water downstream. It occurs when a depth less than critical changes to a depth which is greater than critical and must be accompanied by a loss of energy.
- Page 61 Equipment Set Up Ensure the flume is level, with no stop logs installed at the discharge end of the channel. Measure and record the actual breadth b (m) of the undershot weir. Clamp the undershot weir assembly securely to the sides of the channel close to the upstream end of the flume with the sharp edge on the bottom of the gate facing upstream.
- Page 62 Conclusion Verify the force of the stream on either side of the jump is the same and that the specific ∆ energy curve predicts a loss equal to Suggest an application where the loss of energy in hydraulic jump would be desirable. How is the energy dissipated?
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Page 63: Exercise H: Flow Through A Venturi Flume
To determine the relationship between upstream head and flowrate for water flowing through a Venturi flume. To calculate the discharge coefficient and to observe the flow patterns obtained. Method By using the Venturi flume installed in the C4-MkII flume. Equipment Required Armfield C4-MkII Flume Venturi flume assembly with spreader bar... - Page 64 Theory Widening or narrowing the width of a channel has the same effect as raising or lowering the bed of the channel. Therefore the throat created by a Venturi flume has the same characteristics as the Broad Crested Weir (Exercise B) and the discharge is given by: Equipment Set Up Ensure the flume is level, with no stop logs installed at the end of the flume.
- Page 65 Procedure Open the flow control valve and admit water into the working section. Maintaining a constant flow, measure and note y and Q. Increasing the flow in stages, measure and note the above for each stage. Add stop logs as required to observe the drowned and standing wave flow conditions.
- Page 66 Conclusion Comment on the effects of narrowing the channel. Is it the same as raising the bed? What factors influence the efficiency of the Venturi Flume?
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Page 67: Exercise J: Flow Through A Culvert
To determine the characteristics and observe the flow patterns obtained for water flowing through a Culvert. Method By using the culvert block assembly installed in the C4-MkII flume, and operating the flume at different heads upstream and downstream. Equipment Required... - Page 68 exist. A culvert will run full, like a pipe, when the outlet is submerged or when the upstream level is sufficiently high. The objective is to view the range of patterns which can exist, to determine the head/discharge characteristics and to determine the conditions necessary for the culvert to run full.
- Page 69 Remove the stop logs, drain the culvert then incline the channel bed slightly (flow downhill). Gradually increase the flowrate until the channel runs full as before then record y , Q and S (slope of the bed). Repeat the procedure for increasing slope of the channel bed. If time permits repeat the above experiment for a different height of culvert by adjusting the vertical position of the culvert block.
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Page 70: Exercise K: Flow Around Flow Splitters
To observe the flow patterns obtained for water flowing around splitters with different profiles. Method By operating the C4-MkII with different profiles of flow splitter installed in the flume. Equipment Required Armfield C4-MkII Flume Two Hook and Point Gauges, 300mm scale... - Page 71 The flow splitter represents an obstruction in an open channel, typically the pier of a bridge, the support structure on the top of a dam spillway etc. The effect of the obstruction is similar to a constriction but the flow is split into two streams instead of one.
- Page 72 Procedure Gradually open the flow control valve and allow water to flow along the channel. Add stop logs at the discharge end of the channel to provide a head of water which does not totally submerge the model. Increase the flow in stages, ensuring that the model is not submerged and at each stage observe and sketch the flow pattern around the model then measure and record y and Q.
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Page 73: Exercise L: Flow Over A Dam Spillway
6.14 Exercise L: Flow Over a Dam Spillway Objective To observe the flow patterns associated with the flow of water over a dam spillway Method By operating the C4-MkII flume with the dam spillway fitted, using with different shapes of spillway toe. Equipment Required Armfield C4-MkII Flume... - Page 74 Theory The dam spillway model may be fitted with three different shapes of toe. The flow pattern over each type may be studied through observation as the flume is operated. Equipment Set Up Ensure the flume is level, with no stop logs installed at the discharge end of the channel. Place the dam spillway in the flume towards the inlet end of the working section with the crest facing upstream and the blended reverse curvature toe located beneath the lip.
- Page 75 Procedure The flow over each version of the dam spillway should be varied in stages, by adjusting the flow control valve, and at each stage the flow pattern should be observed and sketched and the flowrate, upstream and downstream water levels recorded. Note: When using the ski jump it should be retained using the stretcher screw provided.
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Page 76: Exercise M: Flow Through A Siphon Spillway
To calculate the discharge coefficient and to observe the operation of the siphon as it primes and de-primes. Method By operating the C4-MkII flume with the siphon spillway fitted. Equipment Required Armfield C4-MkII Flume Two Hook and Point Gauges, 300mm scale... - Page 77 The traditional siphon spillway is shown in the above diagram and consists of a weir with a crest which is covered by a hood to create a barrel. In normal operation the inlet and outlet are both submerged so that air cannot enter the barrel from the outside atmosphere. No flow of water can occur until the upstream level rises above the crest.
- Page 78 Equipment Set Up Ensure the flume is level, with no stop logs installed at the discharge end of the channel. Measure and record the dimensions - breadth b (m) and height z (m) of the throat above the crest inside the siphon. Place the siphon in the flume with the upper leg facing upstream.
- Page 79 Results Tabulate your readings and calculations as follows: Breadth of throat, b……………(m) Height of throat, z……………..(m) Area of throat, A ……...…..….(m Calculate the coefficient of discharge C Conclusion What are the advantages and disadvantages of siphon spillways (“blackwater” siphons)? What is the function of the deflecting nappe?
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Page 80: Exercise N: Flow Through An Air Regulated Siphon
To calculate the discharge coefficient and to observe the operation of the siphon as it primes and de-primes. Method By operating the C4-MkII flume with the air regulated siphon fitted. Equipment Required Armfield C4-MkII Flume Two Hook and Point Gauges, 300mm scale... - Page 81 Theory The air-regulated siphon is a more recent development than the traditional siphon demonstrated in experiment M. It will automatically adjust its discharge over a wide range while maintaining a relatively constant water level upstream. This is achieved by the siphon passing a mixture of air and water continuously. The upstream level is more stable and not prone to hunting.
- Page 82 Phase 2: Deflected nappe Phase 3: Depressed nappe Phase 4: Air Partialised...
- Page 83 Phase 5: “Blackwater” flow The transition from one phase to another is quite gradual and there is no distinct or abrupt change over point. When running full (Phase 5 – blackwater flow) the theoretical discharge through the air- regulated siphon is the same as the blackwater siphon and can be calculated using the equation: Therefore: where:...
- Page 84 measurements will be the bed of the flume. Carefully adjust the level gauges to coincide with the bed of the flume and record the datum readings. Procedure Gradually open the flow control valve and allow the channel upstream of the siphon to fill with water.
- Page 85 Results Tabulate your readings and calculations as follows: Breadth of throat, b =…………(m) Height of throat, z =…………(m) Area of throat A =………..(m Calculate the coefficient of discharge C for the “blackwater” flow condition. Plot the stage discharge characteristics. Conclusion What is the function of the deflecting nappe in the conduit?
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Page 86: Exercise P: Flow Under A Radial Gate
To determine the relationship between upstream head and flowrate beneath a radial gate (Tainter Gate) under different operating conditions. To calculate the discharge coefficient in each condition. Method By using the radial gate assembly installed in the C4-MkII flume. Equipment Required Armfield C4-MkII Flume Two Hook and Point Gauges, 300mm scale... - Page 87 Theory For an underflow gate with free discharge: where: = Volume flowrate = Volume/time (using volumetric tank) = Overall coefficient of discharge (Dimensionless) = Area of the opening = b breadth x height of gate opening y = Upstream depth of flow = Gravitational constant Note: If the downstream side is submerged then y is replaced with (y...
- Page 88 Results Tabulate your readings and calculations as follows: Breadth of gate b, =…………(m) Plot C against for constant Q. Plot C against for constant y Conclusion Comment on the effects of y and Q on the discharge underneath the gate. Which factor has the greatest effect? Comment on discrepancies between actual and expected results.
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Page 89: Exercise Q: Flow Over False Floor Sections
6.18 Exercise Q: Flow Over False Floor Sections Objective To observe the flow patterns associated with the flow of water over different bed profiles. Method By using false floor sections installed in the C4-MkII flume. Equipment Required Armfield C4-MkII Flume Two Hook and Point Gauges, 300mm scale... - Page 90 Equipment Set Up and Procedure The above diagrams show the correct assembly of the three different arrangements of the floor sections. Set up the laminated ramp in the flume ensuring that the flume is level. Open the flow control valve and allow the water to enter the flume. By adjusting the valve, the depth of water can be varied in stages.
- Page 91 Results and Conclusions Compare the flow patterns obtained with each of the different floor sections. Is there any similarity with the flow patterns obtained when using the Broad Crested Weir?
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Page 92: Exercise R: Flow Over A Gravel Bed
To determine the effect of a roughened bed on the depth of water at different flowrates and to obtain appropriate coefficients to satisfy the Manning Formula. Method By using the artificially roughened bed installed in the C4-MkII flume. Equipment Required Armfield C4-MkII Flume... - Page 93 Theory For uniform flow over a gravel bed, the Manning formula states that: where: = Coefficient of roughness (Dimensionless) = mean fluid velocity (m/s) = Hydraulic mean radius = Flow area A / Wetted perimeter P = Slope of energy line = sin θ...
- Page 94 Equipment Set Up Ensure that the flume is horizontal with no stop logs installed at the discharge end. Line the bottom of the flume with the gravel bed section(s). Procedure Using the surface of the bed as a datum, measure and record the datum height. Measure the distance x between the two depth measurement points.
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Page 95: Installation Guide
Installation Guide. Safe use of the equipment depends on following the correct installation procedure. Refer to diagrams on pages 8 and 9 of the C4-MkII Instruction Manual. Note: Two versions of the Multi Purpose Teaching Flume are available as follows: C4-2.5m with a 2.5 metre long working section... - Page 96 When the position of the C4-MkII and F1-10 have been confirmed the two pedestals of the C4-MkII should be bolted to the floor using the 8 masonry bolts supplied (4 bolts on each pedestal). When bolted to the floor it is unlikely that the flume will fall over even if...
- Page 97 F1-10 is switched off and the flow control valve is closed then unscrew the quick release connector from the bed of the channel. Screw the adaptor, supplied with C4-MkII, onto the threaded outlet in the bed of the channel then connect the flexible tube from the C4- MkII to the union on top of the adaptor.
- Page 98 A few drops of wetting agent should be added to the water in the sump tank to minimise the effects of surface tension. Note: If too much wetting agent is added foaming will occur and it will be necessary to replace the water.
- Page 99 The flow control valve can be opened to allow water to drain from the pipework to the sump via the pump. The basic operation of the C4 - MkII has been confirmed. Refer to the Operational Procedures section in the C4-MkII product manual for further information.
- Page 100 Main Office: Armfield Limited Tel: +44 (0)1425 478781 Bridge House Fax: +44 (0)1425 470916 West Street Email sales@armfield.co.uk Ringwood Hampshire http://www.armfield.co.uk England BH24 1DY Web: US Office: Armfield Inc. Tel: (732) 928 3332 436 West Commodore Blvd (#2) Jackson, NJ 08527...
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