Sluices

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

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 Water level control mode has now largely been replaced by logical control rules.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:

where the variables are defined in the following figure:

Figure 1: Radial Sluice Gate parameters

 Equations

see Bos M.G. (1989) Section 8.4

Define

h₁ = y₁ - z_c

h₂ = y₂ - z_c

Mode 0 - Dry Crest

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

Figure 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)

Figure 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

Figure 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)

Figure 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

Figure 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  h0 / 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:

Figure 7: Radial Sluice Gate (Mode 6)

 Mode 7 - Drowned gate flow

Figure 8: Radial Sluice Gate (Mode 7)

 Mode 8 - Free over gate and free under gate flow

Figure 9: Radial Sluice Gate (Mode 8)

 Mode 9 - Free over gate and drowned under gate flow

Figure 10: Radial Sluice Gate (Mode 9)

 Mode 10 - Drowned over gate and drowned under gate flow

Figure11: 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 W_drown, S_drown and T_drown. 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 C_vs, C_vg and C_vw.

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:

where the variables are defined in the following figure:

Figure 1: Vertical Sluice Gate parameters

 Equations

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

Define

h₁ = y₁ - z_c

h₂ = y₂ - z_c

Mode 0 - Dry Crest

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

Figure 2: Vertical Sluice Gate (Mode 1)

 Mode 2 - Gate closed, free flow over gate

Figure 3: Vertical Sluice Gate (Mode 2)

 Mode 3 - Gate closed, drowned flow over gate

Figure 4: Vertical Sluice Gate (Mode 3)

 Mode 4 - Free weir flow under gate

Figure 5: Vertical Sluice Gate (Mode 4)

 Mode 5 - Drowned weir flow under gate

Figure 6: Vertical Sluice Gate (Mode 5)

 Mode 6 - Free gate flow

Figure 7: Vertical Sluice Gate (Mode 6)

 Mode 7 - Drowned gate flow

Figure 8: Vertical Sluice Gate (Mode 7)

 Mode 8 - Free over gate and free under gate flow

Figure 9: Vertical Sluice Gate (Mode 8)

 Mode 9 - Free over gate and drowned under gate flow

Figure 10: Vertical Sluice Gate (Mode 9)

 Mode 10 - Drowned over gate and drowned under gate flow

Figure 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 W_drown, S_drown and T_drown. 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 C_vs, C_vg and C_vw.

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 - C_vw, C_vg, b, z_c, h_g, L, degflg

Line 5 - p₁, p₂, BIAS, C_vs, h_p, R

Line 6 - n_gates, [W_drown, S_drown, T_drown], tm, rptflg

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

Line 8 - keyword `GATE',[description]

Line 9 - n₁

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

Line 10 to Line 9+n₁ - y_1,j, yO_1,j

If O_mode = `time':

Line 10 to Line 9+n₁ - t_1,j, yO_1,j

If O_mode = `controller' or `logical'

Line 10 to Line 9+n₁ - t_1,j, opmode, yO_1,j

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

Line 11+n₁ - n₂

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

Line 12+n₁ to Line 11+n₁+n₂ - y_1,j, yO_1,j

If O_mode = `time':

Line 12+n₁ to Line 11+n₁+n₂ - t_1,j, yO_1,j

If O_mode = `controller' or `logical'

Line 12+n₁ to Line 11+n₁+n₂ - t_1,j, opmode, yO_1,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.

Vertical Sluice Gate Datafile Format

Line 1 - keyword `SLUICE' [comment]

Line 2 - keyword `VERTICAL'

Line 3 - Label1, Label2, [Label3]

Line 4 - C_vw, C_vg, b, z_c, h_g, L

Line 5 - p₁, p₂, BIAS, C_vs, [W_drown, S_drown, T_drown]

Line 6 - n_gates, tm, rptflg

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

Line 8 - keyword `GATE',[description]

Line 9 - n₁

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

Line 10 to Line 9+n₁ - y_1,j, yO_1,j

If O_mode = `time':

Line 10 to Line 9+n₁ - t_1,j, yO_1,j

If O_mode = `controller' or `logical'

Line 10 to Line 9+n₁ - t_1,j, opmode, yO_1,j

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

Line 11+n₁ - n₂

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

Line 12+n₁ to Line 11+n₁+n₂ - y_1,j, yO_1,j

If O_mode = `time':

Line 12+n₁ to Line 11+n₁+n₂ - t_1,j, yO_1,j

If O_mode = `controller' or `logical'

Line 12+n₁ to Line 11+n₁+n₂ - t_1,j, opmode, yO_1,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.