Sluices
    • 31 Oct 2022
    • 25 Minutes to read
    • Dark
      Light

    Sluices

    • Dark
      Light

    Article summary

    This section describes vertical and radial sluice gates.

    Radial Sluice: This unit models a bank of radial sluice gates each of which can be in 11 operating modes depending on upstream and downstream water levels and the gate settings.

    Vertical Sluice: The Vertical Sluice Gate models a bank of vertical sluice gates each of which can be in 11 operating modes depending on upstream and downstream water levels and the gate settings

    Data

    Field in Data Entry Form

    Description

    Name in Datafile

    Upstream

    Upstream node label

    Label1

    Downstream

    Downstream node label

    Label2

    Remote Node Label

    Optional label for gates controlled by water level at a remote node ('water3' mode)

    Label3

    Weir Flow Coefficient

    Coefficient of approach velocity for weir flow (includes multiplicative calibration factor if required)

    Cvw

    Under-Gate Flow Coefficient

    Coefficient of approach velocity for under-gate flow (includes multiplicative calibration factor if required). Dependent on ratio of difference between step and gate seat and height p1 (see Bos M.G. (1989), fig 8.11)

    Cvg

    Breadth of Weir

    Breadth of sluice at control section (normal to the flow) (m)

    b

    Elevation of Crest

    Elevation of weir crest (mAD)

    zc

    Height of Gate /Gate chord

    Height of gate (dimension from bottom to top of gate: i.e. across the chord, if RADIAL) (m)

    hg

    Length of Weir

    Length of weir crest in the direction of flow (m)

    L

    Gate movement specified in Degrees

    Tick this box (deqflq = 'DEGREES') if radial sluice movements are measured, specifically user-entered positions and rules operations, in degrees. Otherwise, vertical opening measurements will be used

    degflg

    Allow free under gate flow

    If checked, free orifice-type flow is permitted

     

    Upstream Weir Height

    Height of crest above bed of upstream channel (m)

    p1

    Downstream Weir Height

    Height of crest above bed of downstream channel (m)

    p2

    Bias Factor

    Biasing factor (1, 2, 3, 4 or 5) applied to water levels used for gate operation in water mode. Water levels over the current and previous four timesteps are weighted as table shows, and then used to determine the gate opening:

    BIAS

    Over-Gate Flow Coefficient

    Coefficient of approach velocity for over-gate flow (includes multiplicative calibration factor if required)

    Cvs

    Height of Gate

    Height of pivot of gate above gate sill (m). Radial Sluice Gate only.

    hp

    Radius of Gate

    Radius of gate (m). Radial Sluice Gate only.

    R

    Number of Gates

    Number of gates (each gate has identical dimensions)

    ngates

    Calculation Method

    If VARIABLE, modular limits will be calculated automatically; if FIXED, user-specified values will be used as below

     

    Modular Limit - Weir

    Modular limit for weir flow. If calculation method is set to FIXED, then Flood Modeller will:

    • use this and the subsequent Sdrown and Tdrown values as fixed modular limits
    • use modified flow equations
    • where water levels indicate that the flow could be in more than one mode it will use the mode giving the lowest flow

    If no value is entered in this field in teh data file (or calculation method is set to VARIABLE) then modular limits will be calculated by the software.

    Wdrown

    Modular Limit – Under Gate Flow

    Modular limit for sluice gate flow. See Wdrown for notes on its significance. Only used if Wdrown is used

    Sdrown

    Modular Limit – Over Gate Flow

    Modular limit for flow over the top of the gate. See Wdrown for notes on its significance. Only used if Wdrown is used

    Tdrown

    Control Method

    Operating mode for gates:

    • time for gate openings controlled according to time
    • water1 for control by water level at upstream node
    • water2 for water level at downstream node
    • water3 for water level at remote node specified by label3
    • control for gates under automatic control from control module
    • logical for gates under control from included logical rules sub-block

    Omode

    Max Movement Rate

    Maximum movement rate of gate (m s-1). This variable is required (and used) only when the sluice is in controller or logical operating modes

    oprate

    Maximum Setting

    Maximum opening of gate (m); this variable is required (and used) only when the sluice is in `controller' mode or `logical' operating modes

    opemax

    Minimum Setting

    Minimum opening of gate (m). This variable is required (and used) only when the sluice is in controller mode or logical operating modes. The default value for this variable is zero

    opemin

    Controller Label

    Label of SETSLUICE unit. This variable is required (and used) only when the sluice is in controller mode

    CLabel

    n/a

    Number of ensuing water level (or time) and gate opening data pairs for jth gate

    nj

    Time

    The time at which the specified operations will apply

     

    Opening

    The i'th specified gate opening for gate number j corresponding to time, ti,j (time mode or MANUAL operation in controller or logical modes) or to weighted (see BIAS) water level, yi,j ('water' modes), where yi,j is at the upstream, downstream or a remote node depending on Omode

    yOi,j

    Mode

    Operating mode (Keyword AUTOMATIC/AUTO or MANUAL/MAN); only for controller or logical modes

    opmode

    Theory and Guidance on Radial Sluice Gate

    This unit models a bank of radial sluice gates each of which can be in 11 operating modes depending on upstream and downstream water levels and the gate settings.

    Up to 10 identically sized radial sluice gates can be modelled in one unit. The dimensions and coefficients are exactly the same for each gate. However, the gate movements can be independently controlled.

    Gate openings can be controlled according to model time, by water levels, by logical rules, or by an associated Rules unit. The gate opening is usually measured in metres above the sill, but an angular opening (in degrees) may also be chosen. An angle of 0° indicates that the gate chord (the gate is represented by a circle segment) is horizontal and below the pivot.

    Time mode operation simply requires the user to define the desired gate opening for a set of model times. In time control, the gate will move at a constant rate between the specified settings during the time between them. In water level control the gate opening is defined according to the water level at the node immediately upstream or downstream of the gate or according to the water level at a remote node. In water level control mode, the gate opening is related to a weighted average of the water level at the previous 5 timesteps to prevent hunting of the gates. Water level control mode has now largely been replaced by logical control rules.

    When in logical mode the sluice will use logical rules that are contained within a specific Rules data block to control the movements of all of its gates; this data block must appear immediately after the main part of the sluice datafile entry. For full details of how to use this option, please refer to the Rules topic.

    In addition to the standard operating modes described above, there is an additional mode of operation: controller' mode. When the sluice is in controller mode all of the sluice gates will be controlled by commands from the control system model.

    Please note that in controller and logical operation modes it is not possible to control individual gates within a sluice unit independently of each other. If this facility is required, the user must have one single-gated sluice unit in the datafile for each sluice gate.

    When operating in either controller or logical mode there are two sub-modes of operation; automatic and manual control. Sluice gates can switch freely between these two modes of operation depending on the instructions the user has put into the datafile entry.
    When in automatic mode the sluice gates will be driven from instructions from connected control units (in controller mode) or by currently valid rules within the RULES data (in logical mode). These instructions will be updated when the polling time interval has elapsed. Instructions are interpreted as a command to move to a target gate position - between fully closed and the maximum opening value - and the sluice gates will be moved to this target position at the maximum movement rate over the subsequent polling time interval.

    When operating in manual control mode the target gate positions are obtained from the appropriate line of the time switch data in the datafile entry for the controlled sluice unit. When the model time reaches or exceeds the time value in the switch data, the sluice unit will move all of its gates to the corresponding gate opening value, moving at the maximum rate possible.

    Note that when in manual mode the sluice gates will attempt to move instantaneously from one setting to another (i.e. intermediate positions are not obtained via linear interpolation, as they are in Time control mode).

    Flow beneath the sluice gate where the gate does not interfere with the flow is described by the round nosed horizontal broad crested weir equations. Drowned or free orifice equations are used when the gate does interfere with the flow.

    Flow over the gate top is represented by equations for a sharp crested weir. Simultaneous overshoot and undershoot flow are allowed. 11 different modes of flow are covered.

    Each gate may have a different opening and hence a different mode of flow at a particular time. Unit mode and unit state (gate opening) are the average mode and state for all gates and are output against the upstream node label (ie the first label).

    Reverse flow through the gates is allowed and assumes that the same coefficients prevail.

    The radius of curvature at the leading edge of the weir crest is set to be 0.1
    metres.

    The modular limit for weir flow is taken from Figure 4.2 in Bos M.G. (1989) using the mean line between the relationship for a radial back face and a sloping (1 to 4) back face as follows:

    log10 (h1/p2)

    m ( = h2/h1)

    (or m = (h2-hg) / (h1-hg) for overgate flow)

    -10

    0.71

    -1

    0.72

    0

    0.89

    0.3

    0.93

    0.48

    0.95

    1

    0.98

    1020

    0.98

    where the variables are defined in the following figure:

    RiverNodesimagesRadialSluiceMeasurements.gifFigure 1: Radial Sluice Gate parameters

     Equations

    see Bos M.G. (1989) Section 8.4

    Define

    h1 = y1 - zc

    h2 = y2 - zc

    Mode 0 - Dry Crest

    Condition

    h1 £ 0.005 (L-r)

    Equation

    Q = 0

    Mode 1 - Gate closed, upstream and downstream level below gate top

    Condition

    ho < 0.001

    h1 - hg £ 0.005 (L-r)

    Equation

    Q = 0

    RiverNodesimagesRadialSluiceMode1.gifFigure 2: Radial Sluice Gate (Mode 1)

     Mode 2 - Gate closed, free flow over gate

    Condition

    ho < 0.001

    (h1-hg) > 0

    (h2-hg) / (h1-hg) £ m

    where:

    m is the modular limit

    Equation

    Q = Cvs Ce 2/3 (2g)0.5 b(h1 - hg - ho)1.5

    (1)

    where:

    Ce = 0.602 + 0.075 (h1 - hg - ho) / (p1 + hg + ho)

    g = gravitational acceleration (m/s2)

    Fixed Modular Limit Equation

    Q = Cvs 1.705 b(h1 - hg - ho)1.5

    (1a)

    RiverNodesimagesRadialSluiceMode2.gifFigure 3: Radial Sluice Gate (Mode 2)

     Mode 3 - Gate closed, drowned flow over gate

    Condition

    ho < 0.001

    (h1 - hg) > 0

    (h2 - hg) / (h1 - hg) > m

    Equation

    Q = Crf Ce Cvs 2/3 Ö (2g) b (h1 - hg - ho)1.5

    (2)

    where:

    Ce = 0.602 + 0.075 (h1 - hg - ho) / (p1 + hg + ho)

    Crf = [ 1 - (h2 - hg - ho)1.5 / (h1 - hg - ho)1.5 ]0.385

    g = gravitational acceleration (m/s2)

    Fixed Modular Limit Equation

    Q = Cvs 1.705 b(h1 - hg - ho)1.5 f(h1 - hg - ho, h2 - hg - ho)

    (2a)

    where:

    f is a function defined in Mode 5 below

    RiverNodesimagesRadialSluiceMode3.gifFigure 4: Radial Sluice Gate (Mode 3)

     Mode 4 - Free weir flow under gate

    Condition

    ho ³  0.001

    h2/h1 £  m

    0.005(L - r) < h1 < 1.5 ho

    h2 < ho

    Equation

    Q = Cd Cvw (2/3)1.5 Ög b h11.5

    (3)

    where:

    Cd = [ 1 - d  (L - r ) / b ] [ 1 - (d  / 2h1) (L - r) ]1.5

    r = 0.1

    d  = 0.01

    g = gravitational acceleration (m/s2)

    Fixed Modular Limit Equation

    Q = Cvw (2/3)1.5 Ö g b h11.5

    (3a)

    RiverNodesimagesRadialSluiceMode4.gifFigure 5: Radial Sluice Gate (Mode 4)

     Mode 5 - Drowned weir flow under gate

    Condition

    ho ³  0.001

    h2/h1 > m

    0.005(L - r) < h1 < ho

    Equation

    Q = Cd Cvw (2/3)1.5 Ö g b h1 [ (h1 - h2) / (1 - m) ]0.5

    (4)

    where:

    Cd = [ 1 - d  (L - r ) / b ] [ 1 - (d  / 2h1) (L - r) ]1.5

    r = 0.1

    d  = 0.01

    g = gravitational acceleration (m/s2)

    Fixed Modular Limit Equation

    Q = Cvw (2/3)1.5 Ö g b h11.5 f(h1, h2)

    (4a)

    where:

    when m £ (h2 / h1) £ 0.91 + 0.09m

    or:

     when the above condition is untrue

    RiverNodesimagesRadialSluiceMode5.gifFigure 6: Radial Sluice Gate (Mode 5)

     Mode 6 - Free gate flow

    Condition

    ho ³  0.001

    h1 ³  1.5 ho  

    h2/ho < ( a / 2) { Ö (1 + 16 [ h1 / (ah0) - 1 ] ) - 1 }

    Equation

    Q = Cd Cvg Ö (2g) b ho h1 0.5

    (5)

    where:

    Cd = a  / (1 + a  h/ h1 )0.5

    a  = 1 - 1.5(q  / p ) + 1.44(q  / p )2

    cosq   = (hp  - hq ) / r

    g = gravitational acceleration (m/s2)

    Fixed Modular Limit Equation

    (5a)

    where:

    f = 1.0 when j ³ 0.520 (free flow Mode 6)

    or:

     when j < 0.520 (drowned flow Mode 7)

    where:

    RiverNodesimagesRadialSluiceMode6.gifFigure 7: Radial Sluice Gate (Mode 6)

     Mode 7 - Drowned gate flow

    Condition

    h0 ³  0.001

    h1 ³  1.5 h0

    h2/h0 ³  a /2 { Ö ( 1 + 16[ h1 / (ah0) - 1 ] ) -1 }

    Equation

    Q = Cd Cvg b ho Ö(2g) (h1 - h2)0.5

    (2)

    where:

    Cd = a  / [ 1 - ( a h0 / h1)2 ]0.5

    a  = 1 - 1.5(q  / p ) + 1.44(q / p )2

    cosq  = (hp - hq ) / R

    g = gravitational acceleration (m/s2)

    Fixed Modular Limit Equation

    see Mode 6

    RiverNodesimagesRadialSluiceMode7.gifFigure 8: Radial Sluice Gate (Mode 7)

     Mode 8 - Free over gate and free under gate flow

    Condition

    As Mode 6 and:

    (h1 - hg) > 0

    Equation

    Sum of Mode 6 and Mode 2 equations.

    RiverNodesimagesRadialSluiceMode8.gifFigure 9: Radial Sluice Gate (Mode 8)

     Mode 9 - Free over gate and drowned under gate flow

    Condition

    As Mode 7 and:

    (h1 - hg) > 0

    (h2 - hg) £ 0

    Equation

    Sum of Mode 7 and Mode 2 equations.

    RiverNodesimagesRadialSluiceMode9.gifFigure 10: Radial Sluice Gate (Mode 9)

     Mode 10 - Drowned over gate and drowned under gate flow

    Condition

    As Mode 7 and:

    (h1 - hg) > 0

    (h2 - hg) > 0

    Equation

    Sum of Mode 7 and Mode 3 equations.

    RiverNodesimagesRadialSluiceMode10.gifFigure11: Radial Sluice Gate (Mode 10)

     General

    The equation for drowned weir flow is based on the Bernoulli equation constrained to a smooth transition between free and drowned flow at the modular limit. There is no experimental or theoretical equation in the literature for this mode of flow.

    The equations are couched in terms of water levels with a coefficient of velocity rather than using total head.

    There are discontinuities between the equations for certain modes of flow, for example the transition from free gate to free weir flow can lead to a sudden change in flow for the same head or vice versa. This can lead to hunting between some of the different modes. There is no information in the literature on transitions between modes for sluices.

    If poor convergence problems are found to be caused by this unit then you may wish to try the alternative solution technique available by setting the fixed modular limit values Wdrown, Sdrown and Tdrown. The alternative technique is likely to reduce hunting between different modes of operation.

    Care must be taken with the specification of sensible control rules. In `water' control modes, for example, it is possible to specify the control rules such that there are regions where no equations apply.

    It is recommended that logical control rules are used in preference to water control modes.

    The test for change from weir flow to under gate flow (and vice versa) assumes that the gate is located at a point on the sill where critical flow occurs. Hence the upstream water depth above the sill must be 50% greater than the gate opening before under-gate flow equations come into action.

    The equations used are a strict application of those found in Bos M.G. (1989). Losses due to side effects, unusual piers, angled approach direction, etc need to be taken into account in the coefficients Cvs, Cvg and Cvw.

    When using `controller' or `logical' modes, if the datafile is set up so that for a particular run a sluice gate starts up in `AUTO' mode, the sluice gate opening will initially be set to the value given in the unit state (ustate) field in the initial conditions. If this is outside the possible range, the corresponding datafile entry in the switch data set must have a gate opening value, which will be used. Other `AUTO' entries in the switch data set need not have a corresponding speed value as the sluice will receive its target gate positions from the control system or from the logical rules sub-block. If gate openings are given in this instance they will be ignored by the controlled sluice unit.

    When starting in `AUTO' mode for `controller' operation, it may be necessary to ensure that the initial gate openings in the switch data set are compatible with the initial output value from the corresponding SETSLUICE unit. Otherwise the signal from the control system may result in a large initial change in gate opening.

    For reasons of stability it is often desirable to run the controlled sluice unit in MANUAL mode for a short time even if an automatic run is required in `controller' mode. This is to ensure that control unit variables (such as outputs, errors, etc.) can stabilise without any interfering feedback effects.

    Combinations of different dimension sluice gates in a hydraulic complex may be modelled by grouping gates of the same dimension into one of several units, and connecting each unit by a JUNCTION.

    The direct steady solver may not be used on models containing this unit type if any gates are operating in `remote water' mode.

    In default mode, the unit state for this unit is the average gate opening (in metres). If the Gate movements measured in degrees option is chosen, the unit state is the deviation from vertical in degrees of the line of symmetry of the gate.

    Theory and Guidance on Vertical Sluice Gate

    The Vertical Sluice Gate models a bank of vertical sluice gates each of which can be in 11 operating modes depending on upstream and downstream water levels and the gate settings.

    Up to 10 identically sized vertical sluice gates can be modelled in one unit. The dimensions and coefficients are exactly the same for each gate. However the gate movements can be independently controlled.

    Gate openings can be controlled according to model time, by water levels, by logical rules, or by an associated Rules unit.

    Time mode operation simply requires the user to define the desired gate opening for a set of model times. In time control, the gate will move at a constant rate between the specified settings during the time between them. In water level control the gate opening is defined according to the water level at the node immediately upstream or downstream of the gate or according to the water level at a remote node. In water level control mode the gate opening is related to a weighted average of the water level at the previous 5 time steps to prevent hunting of the gates. Water level control mode has now largely been replaced by logical control rules.

    When in logical mode the sluice will use logical rules that are contained within a specific Rules unit to control the movements of all of its gates; this data block must appear immediately after the main part of the sluice datafile entry. For full details of how to use this option, please refer to the Rules topic.

    In addition to the standard operating modes described above, there is an additional mode: 'controller' mode. When the sluice is in controller mode all of the sluice gates will be controlled by commands from the control system model.

    Please note that in controller and logical operation modes it is not possible to control individual gates within a sluice unit independently of each other. If this facility is required the user must have one single-gated sluice unit in the datafile for each sluice gate.

    When operating in either controller or logical mode there are two sub-modes of operation; automatic and manual control. Sluice gates can switch freely between these two modes of operation depending on the instructions the user has put into the unit data.

    When in automatic mode the sluice gates will be driven from instructions from connected control units (in controller mode) or by currently valid rules within the RULES data block (in logical mode). These instructions will be updated when the polling time interval has elapsed. Instructions are interpreted as a command to move to a target gate position - between fully closed and the maximum opening value - and the sluice gates will be moved to this target position at the maximum movement rate over the subsequent polling time interval.

    When operating in manual control mode the target gate positions are obtained from the appropriate line of the time switch data in the datafile entry for the controlled sluice unit. When the model time reaches or exceeds the time value in the switch data, the sluice unit will move all of its gates to the corresponding gate opening value, moving at the maximum rate possible.

    Note that when in manual mode the sluice gates will attempt to move instantaneously from one setting to another (i.e. intermediate positions are not obtained via linear interpolation, as they are in Time control mode).

    Flow beneath the sluice gate where the gate does not interfere with the flow is described by the round nosed horizontal broad crested weir equations. Drowned or free orifice equations are used when the gate does interfere with the flow.

    Flow over the gate top is represented by equations for a sharp crested weir. Simultaneous overshoot and undershoot flow are allowed. 11 different modes of flow are covered.

    Each gate may have a different opening and hence a different mode of flow at a particular time. Unit mode and unit state (gate opening) are the average mode and state for all gates and are output against the upstream node label (ie the first label).

    Reverse flow through the gates is allowed and assumes that the same coefficients prevail.

    The radius of curvature at the leading edge of the weir crest is set to be 0.1 metres.

    The modular limit for weir flow is taken from Harrison (1967) (also Figure 4.2 in Bos M.G. (1989)) using the mean line between the relationship for a vertical back face and a sloping (1 to 4) back face as follows:

    log10 (h1/p2)m ( = h2/h1 )
    ( or m = (h2-hg) / (h1-hg) for overgate flow )

    -10

    0.71

    -1

    0.72

    0

    0.89

    0.3

    0.93

    0.48

    0.95

    1

    0.98

    1020

    0.98

    where the variables are defined in the following figure:

    RiverNodesimagesVertSluiceMeasurements.gifFigure 1: Vertical Sluice Gate parameters

     Equations

    See Bos M.G. (1989) Chapters 8 and 9.

    Define

    h1 = y1 - zc

    h2 = y2 - zc

    Mode 0 - Dry Crest

    Condition

    h1 £  0.005 (L-r)

    Equation

    Q = 0

    Mode 1 - Gate closed, upstream and downstream level below gate top

    Condition

    ho < 0.001

    h1 - hg £ 0.005 (L-r)

    Equation

    Q = 0

    RiverNodesimagesVertSluiceMode1.gifFigure 2: Vertical Sluice Gate (Mode 1)

     Mode 2 - Gate closed, free flow over gate

    Condition

    ho < 0.001

    (h1-hg) > 0

    (h2-hg) / (h1-hg) £  m

    where:

    m is the modular limit

    Equation

    Q = Cvs Ce 2/3 (2g)0.5 b(h1 - hg - ho)1.5

    (1)

    where:

    Ce = 0.602 + 0.075 (h1 - hg - ho) / (p1 + hg + ho)

    g = gravitational acceleration (m/s2)

    Fixed Modular Limit Equation

    Q = Cvs 1.705 b(h1 - hg - ho)1.5

    (1a)

    RiverNodesimagesVertSluiceMode2.GIFFigure 3: Vertical Sluice Gate (Mode 2)

     Mode 3 - Gate closed, drowned flow over gate

    Condition

    ho < 0.001

    (h1 - hg) > 0

    (h2 - hg) / (h1 - hg) > m

    Equation

    Q = Crf Ce Cvs 2/3 Ö (2g) b (h1 - hg - ho)1.5

    (2)

    where:

    Ce = 0.602 + 0.075 (h1 - hg - ho) / (p1 + hg + ho)

    Crf = [ 1 - (h2 - hg - ho)1.5 / (h1 - hg - ho)1.5 ]0.385

    g = gravitational acceleration (m/s2)

    Fixed Modular Limit Equation

    Q = Cvs 1.705 b(h1 - hg - ho)1.5 f(h1 - hg - ho, h2 - hg - ho)

    (2a)

    where:

    f is a function defined in Mode 5 below

    RiverNodesimagesVertSluiceMode3.GIFFigure 4: Vertical Sluice Gate (Mode 3)

     Mode 4 - Free weir flow under gate

    Condition

    ho ³  0.001

    h2/h1 £  m

    0.005(L - r) < h1 < 1.5 ho

    h2 < ho

    Equation

    Q = Cd Cvw (2/3)1.5 Ö g b h11.5

    (3)

    where:

    Cd = [ 1 - d  (L - r ) / b ] [ 1 - (d  / 2h1) (L - r) ]1.5

    r = 0.1

    d  = 0.01

    g = gravitational acceleration (m/s2)

    Fixed Modular Limit Equation

    Q = Cvw (2/3)1.5 Ö g b h11.5

    (3a)

    RiverNodesimagesVertSluiceMode4.GIFFigure 5: Vertical Sluice Gate (Mode 4)

     Mode 5 - Drowned weir flow under gate

    Condition

    ho ³ 0.001

    h2/h1 > m

    0.005(L - r) < h1 < ho

    Equation

    Q = Cd Cvw (2/3)1.5 Ö g b h1 [ (h1 - h2) / (1 - m) ]0.5

    (4)

    where:

    Cd = [ 1 - d  (L - r ) / b ] [ 1 - (d  / 2h1) (L - r) ]1.5

    r = 0.1

    d  = 0.01

    g = gravitational acceleration (m/s2)

    Fixed Modular Limit Equation

    Q = Cvw (2/3)1.5 Ö g b h11.5 f(h1, h2)

    (4a)

    where:

    when m £ (h2 / h1) £ 0.91 + 0.09m

    or:

     when the above condition is untrue

    RiverNodesimagesVertSluiceMode5.GIFFigure 6: Vertical Sluice Gate (Mode 5)

     Mode 6 - Free gate flow

    Condition

    ho ³  0.001

    h1 ³  1.5 ho

    h2/ho < ( a  / 2) { Ö (1 + 16 [ h1 / (aho) - 1 ] ) - 1 }

    Equation


    (5)

    where:

    a = Contraction Coefficient (see Bos M.G. (1989) Table 8.3)

    Fixed Modular Limit Equation

    (5a)

    where:

    f = 1.0 when j ³ 0.520 (free flow Mode 6)

    or:

     when j < 0.520 (drowned flow Mode 7)

    where:

    RiverNodesimagesVertSluiceMode6.GIFFigure 7: Vertical Sluice Gate (Mode 6)

     Mode 7 - Drowned gate flow

    Condition

    ho ³  0.001

    h1 ³  1.5 ho

    h2/ho ³  a  /2 { Ö ( 1 + 16[ h1 / (aho) - 1 ] ) -1 }

    Equation

    Q = Ce Cvg b ho Ö (2g) (h1 - h2)0.5

    (2)

    where:

    Ce = 0.61 [ 1 + 0.15(b + 2ho) / (2b + 2ho) ]

    a  = Contraction Coefficient (see Bos M.G. (1989) Table 8.3)

    Fixed Modular Limit Equation

    see Mode 6

    RiverNodesimagesVertSluiceMode7.GIFFigure 8: Vertical Sluice Gate (Mode 7)

     Mode 8 - Free over gate and free under gate flow

    Condition

    As Mode 6 and:

    (h1 - hg) > 0

    Equation

    Sum of Mode 6 and Mode 2 equations.

    RiverNodesimagesVertSluiceMode8.GIFFigure 9: Vertical Sluice Gate (Mode 8)

     Mode 9 - Free over gate and drowned under gate flow

    Condition

    As Mode 7 and:

    (h1 - hg) > 0

    (h2 - hg) £ 0

    Equation

    Sum of Mode 7 and Mode 2 equations.

    RiverNodesimagesVertSluiceMode9.GIFFigure 10: Vertical Sluice Gate (Mode 9)

     Mode 10 - Drowned over gate and drowned under gate flow

    Condition

    As Mode 7 and:

    (h1 - hg) > 0

    (h2 - hg) > 0

    Equation

    Sum of Mode 7 and Mode 3 equations.


    RiverNodesimagesVertSluiceMode10.GIFFigure 11: Vertical Sluice Gate (Mode 10)

     General

    The equation for drowned weir flow is based on the Bernoulli equation constrained to a smooth transition between free and drowned flow at the modular limit. There is no experimental or theoretical equation in the literature for this mode of flow.

    The equations are couched in terms of water levels with a coefficient of velocity rather than using total head.

    There are discontinuities between the equations for certain modes of flow, for example the transition from free gate to free weir flow can lead to a sudden change in flow for the same head or vice versa. This can lead to hunting between different modes. There is no information in the literature on transitions between some of the modes for sluices.

    If poor convergence problems are found to be caused by this unit then you may wish to try the alternative solution technique available by setting the fixed modular limit values Wdrown, Sdrown and Tdrown. The alternative technique is likely to reduce hunting between different modes of operation.

    Care must be taken with the specification of sensible control rules. In `water' control modes, for example, it is possible to specify the control rules such that there are regions where no equations apply.

    It is recommended that logical control rules are used in preference to water control modes.

    The test for change from weir flow to under gate flow (and vice versa) assumes that the gate is located at a point on the sill where critical flow occurs. Hence the upstream water depth above the sill must be 50% greater than the gate opening before under-gate flow equations come into action.

    The equations used are a strict application of those found in Bos M.G. (1989). Losses due to side effects, unusual piers, angled approach direction, etc need to be taken into account in the coefficients Cvs, Cvg and Cvw.

    When using `controller' or `logical' modes, if the datafile is set up so that for a particular run a sluice gate starts up in `AUTO' mode, the sluice gate opening will initially be set to the value given in the unit state (ustate) field in the initial conditions. If this is outside the possible range, the corresponding datafile entry in the switch data set must have a gate opening value, which will be used. Other `AUTO' entries in the switch data set need not have a corresponding gate opening value as the sluice will receive its target gate positions from the control system or from the logical rules sub-block. If gate openings are given in this instance they will be ignored by the controlled sluice unit.

    When starting in `AUTO' mode for `controller' operation, it may be necessary to ensure that the initial gate openings in the switch data set are compatible with the initial output value from the corresponding SETSLUICE unit. Otherwise the signal from the control system may result in a large initial change in gate opening.

    For reasons of stability it is often desirable to run the controlled sluice unit in MANUAL mode for a short time even if an automatic run is required in `controller' mode. This is to ensure that control unit variables (such as outputs, errors, etc.) can stabilise without any interfering feedback effects.

    Combinations of different dimension sluice gates in a hydraulic complex may be modelled by grouping gates of the same dimension into one of several units, and connecting each unit by a JUNCTION.

    The direct steady solver can not be used on models containing units of this type if any of the gates are operating in `remote water', `controller' or `logical' modes.

    The unit state for this unit is the average gate opening (in metres).

    Radial Sluice Gate Datafile Format

    Line 1 - keyword `SLUICE' [comment]

    Line 2 - keyword `RADIAL'

    Line 3 - Label1, Label2, [Label3]

    Line 4 - Cvw, Cvg, b, zc, hg, L, degflg

    Line 5 - p1, p2, BIAS, Cvs, hp, R

    Line 6 - ngates, [Wdrown, Sdrown, Tdrown], tm, rptflg

    Line 7 - Omode, [oprate, opemax, opemin, CLabel]

    Line 8 - keyword `GATE',[description]

    Line 9 - n1

    If Omode = `water1' or `water2' or `water3':

    Line 10 to Line 9+n1 - y1,j, yO1,j

    If Omode = `time':

    Line 10 to Line 9+n1 - t1,j, yO1,j

    If Omode = `controller' or `logical'

    Line 10 to Line 9+n1 - t1,j, opmode, yO1,j

    Line 10+n1 - keyword `GATE', [description]

    Line 11+n1 - n2

    If Omode = `water1' or `water2' or `water3':

    Line 12+n1 to Line 11+n1+n2 - y1,j, yO1,j

    If Omode = `time':

    Line 12+n1 to Line 11+n1+n2 - t1,j, yO1,j

    If Omode = `controller' or `logical'

    Line 12+n1 to Line 11+n1+n2 - t1,j, opmode, yO1,j

    Note:

    1. The last 3 lines are repeated for each gate in turn.
    2. The RULES sub-block should appear immediately after this unit if `logical' operating mode is to be used - see the Rules section.

    RiverNodesimagesRadialSluiceData.gif

    Vertical Sluice Gate Datafile Format

    Line 1 - keyword `SLUICE' [comment]

    Line 2 - keyword `VERTICAL'

    Line 3 - Label1, Label2, [Label3]

    Line 4 - Cvw, Cvg, b, zc, hg, L

    Line 5 - p1, p2, BIAS, Cvs, [Wdrown, Sdrown, Tdrown]

    Line 6 - ngates, tm, rptflg

    Line 7 - Omode, [oprate, opemax, opemin, CLabel]

    Line 8 - keyword `GATE',[description]

    Line 9 - n1

    If Omode = `water1' or `water2' or `water3':

    Line 10 to Line 9+n1 - y1,j, yO1,j

    If Omode = `time':

    Line 10 to Line 9+n1 - t1,j, yO1,j

    If Omode = `controller' or `logical'

    Line 10 to Line 9+n1 - t1,j, opmode, yO1,j

    Line 10+n1 - keyword `GATE', [description]

    Line 11+n1 - n2

    If Omode = `water1' or `water2' or `water3':

    Line 12+n1 to Line 11+n1+n2 - y1,j, yO1,j

    If Omode = `time':

    Line 12+n1 to Line 11+n1+n2 - t1,j, yO1,j

    If Omode = `controller' or `logical'

    Line 12+n1 to Line 11+n1+n2 - t1,j, opmode, yO1,j

    Note:

    1. The last 3 lines are repeated for each gate in turn.
    2. The RULES sub-block should appear immediately after this unit if `logical' operating mode is to be used - see the Rules section.

    RiverNodesimagesVerticalSluiceData.gif


    Was this article helpful?

    What's Next
    Changing your password will log you out immediately. Use the new password to log back in.
    First name must have atleast 2 characters. Numbers and special characters are not allowed.
    Last name must have atleast 1 characters. Numbers and special characters are not allowed.
    Enter a valid email
    Enter a valid password
    Your profile has been successfully updated.