Constant pump capacity (m3/s)
Free flow weir function:
Q = Cd . b . 2/3 . sqrt( 2/3 . g) (H1)^(3/2)
Drowned flow weir function:
Q = Cd . b . (H1) . sqrt(2g (h1 - h2))
Weir goes from free flowing to drowned under following conditions:
Free weir flow applied when:
H2 > freeFlowLimitCoefficient. H1
Drowned weir flow applied when:
H2 <= freeFlowLimitCoefficient. H1
Height of weir (m).
Measured from upstream bed level to crest of weir.
If crest level is omitted application assumes that weir is movable and a crest level value is expected as calculation input.
width of weir (m)
Limit coefficient defines when weir goes from free flowing to drowned flowing.
Discharge coefficient (-) for free flowing weir.
Discharge coefficient (-) for drowned flowing weir.
Free flow weir function:
Q = freeFlowExpression
Drowned flow weir function:
Q = drownedFlowExpression
Weir goes from free flowing to drowned under following conditions:
Free weir flow applied when:
H2 > freeFlowLimitCoefficient. H1
Drowned weir flow applied when:
H2 <= freeFlowLimitCoefficient. H1
For the user defined weir functions the following INPUT variables are supported by the UserDefinedWeir.class:
upstream water level = "h1"
downstream water level = "h2"
weir height = "hc"
for triangular weirs
height of vertex above the bottom = "hc"
height of triangle = "htr"
Limit coefficient defines when weir goes from free flowing to drowned flowing.
Height of weir (m).
Measured from upstream bed level to crest of weir.
If crest level is omitted application assumes that weir is movable and a crest level value is expected as calculation input.
Width of the weir opening (m)
Length (m) between front of weir and back of weir.
Height of weir (m).
Measured from upstream bed level to crest of weir.
If crest level is omitted application assumes that weir is movable and a crest level value is expected as calculation input.
Width of the weir opening (m)
Height of triangle (m)
Difference in level between vertex height and top of crest.
Only required for triangular weirs.
Height of triangle (m)
Difference in level between vertex height and top of crest.
Only required for triangular weirs.
Free orifice flow function:
flow = contraction coef. * discharge coef. * width * opening height * sqrt(2*g*(upstream level - (crest level + contraction coef. * opening height)))
Drowned orifice flow function:
flow = contraction coef. * discharge coef. * width * opening height * sqrt(2*g*(upstream level - downstream level))
Orifice goes from free flowing to drowned under following conditions:
Free orifice flow applied when:
upstream level - crest level > flowLimitCoefficient * openings height and
downstream level < crest level + openings height
Drowned orifice flow applied when:
upstream level - crest level > flowLimitCoefficient * openings height and
downstream level > crest level + openings height
Opening level of gate bottom (m).
If gate level is omitted application assumes that gate is movable and a gate level value is expected as calculation input.
Discharge coefficient (-) for free flowing orifice.
Contraction coefficient (-) for free flowing orifice
Discharge coefficient (-) for drowned flowing orifice.
Discharge coefficient (-) for drowned flowing orifice
TODO: RENAME
Percent of the maximum defined pump capacity (-)
Pumping capacity (m3/s) for given head an factor (optional).
Level difference (m) between upstream level and downstream level.
Head is positive in case of pumping from lower level to higher level.
Pumping capacity (m3/s) for given head an factor (optional).
TODO: RENAME
Percent of the maximum defined pump capacity (-)
Level difference (m) between upstream level and downstream level.
Head is positive in case of pumping from lower level to higher level.
Pumping capacity (m3/s) for given head an factor (optional).
Parameters:
• hr = reference level
• P = height of weir or height of vertex above bottom
• L = length of weir
• b = width of weir opening of width of triangle
• h1 = upstream water level
• H1 = upstream energy level
• H2 = downstream energy level
• htr = height of triangle
• B = width of channel
• ha = height of opening
Free flow weir function:
Q = Cg . Cd . b . H1^3/2
Cg = (2/3)^(3/2) sqrt(g)
Cd = freeDischargeCoefficient
Drowned flow weir function:
Q = Cg . Cd . b . H1 . sqrt(h1 - h2)
Cg = sqrt(2g)
Cd = drownedDischargeCoefficient
Weir goes from free flowing to drowned under following conditions:
Free weir flow applied when:
H2 < flowLimitCoefficient . H1
Drowned weir flow applied when:
H2 > flowLimitCoefficient . H1
Free flow weir function:
Q = freeFlowExpression
Drowned flow weir function:
Q = drownedFlowExpression
Weir goes from free flowing to drowned under following conditions:
Free weir flow applied when:
H2 > freeFlowLimitCoefficient. H1
Drowned weir flow applied when:
H2 <= freeFlowLimitCoefficient. H1
Q = Cg . Cd . b . H1^(3/2)
Cg = (2/3)^(3/2) sqrt(g)
Cd = 0.86
for h1/P <= 0.5 and h1/L <= 0.3
Cd = 0.888 - 0.093(h1/P) + 0.133(h1/P)^2 - 0.021(h1/P)^3 - 0.151(h1/L) + 0.102(h1/L)(h1/P) - 0.065(h1/L)(h1/P)^2 + 0.310(h1/L)^2
+ 0.028(h1/L)^2(h1/P) - 0.102(h1/L)^3
The modular limit is obtained from:
H2/H1 = 0.66 for H1/L <= 0.33
H2/H1 = 0.66 - 0.24 (H1/L - 0.33) for 0.33 < H1/L <= 1.5
H2/H1 = 0.38 for H1/L <= 1.5
In case the modular limit is exceeded a missing value is entered for the discharge.
Q = Cg . Cd . b . H1^(3/2)
Cg = (2/3)^(3/2) sqrt(g)
Cd = (1 - 0.0006L/b) (1- 0.003L/h1)^(3/2)
The modular limit is obtained from:
H2/H1 = 0.855 + 0.070 ln (H1/P) for H1/P < 2
H2/H1 = 0.869 + 0.049 ln (H1/P) for H1/P >= 2
In case the modular limit is exceeded a missing value is entered for the discharge.
Q = Cg . Cd . b . H1^(3/2)
Cg = (2/3)^(3/2) sqrt(g)
Cd = 0.9564 + 1.018 (H1/L) - 3.530(H1/L)^2 + 4.936(H1/L)^3 - 2.302(H1/L)^4
The validity range for calculating the Cd values is : 0.08 < H1/L < 0.78
The modular limit is obtained from:
H2/H1 = 0.30
In case the modular limit is exceeded a missing value is entered for the discharge.
Two cases are distinguished:
a. H1 <= 1.25 htr, then:
Q = Cg . Cd . H1^(5/2)
Cg = 16/25 sqrt(2/5 g) b/2 hrt
b. H1 > 1.25 htr, then:
Q = Cg . Cd . b . (H1 - hrt/2)^(3/2)
Cg = (2/3)^(3/2) sqrt(g)
Cd = 0.764 + 1.895 (H1/L) - 6.204 (H1/L)^2 + 6.944 (H1/L)^3
for H1/L <= 0.25
Cd = 0.937 + 0.089 (H1/L)
for H1/L > 0.25
The modular limit is obtained from:
for H1 <= 1.25 htr : H2/H1 = 0.80
for H1 > 1.25 htr : equations for the round nose horizontal crest weir with
P replaced by P + 1/2 htr
In case the modular limit is exceeded a missing value is entered for the discharge.
Q = Cg . Cd . b . H1^(3/2)
Cg = (2/3)^(3/2) sqrt(g)
Cd = 0.848
for h1/L < 0.43
Cd = 0.765 + 0.194(h1/L) - 0.0003(h1/L)^2
for h1/L >= 0.43
The modular limit is given by equations of the rectangular profile weir. In case the modular limit is exceeded a missing value is entered for the discharge.
Q = Cg . Cd . be . he^(3/2)
Cg = 2/3 sqrt( 2 g )
Cd = a + c h1/P
where:
a = 0.587 + 0.01 b/B
for b/B <= 0.7
a = 0.610 - 0.056 (b/B) + 0.048 (b/B)^2
for b/B > 0.7
c = -0.002
for b/B <= 0.2
c = 0.0016 - 0.0367 (b/B) + 0.1127 (b/B)^2
for b/B > 0.2
he = h1 + 0.001
be = b + 0.003
The following limitations apply on the use of the above formulae:
b >= 0.15 m
P >= 0.10 m
he >= 0.03 m
h1/P <= 2.0
h1 <= ha and h2 <= -0.05 m
Q = Cg . Cd . h1^(5/2)
Cg = 8/15 sqrt(2 g) tg(b / 2hrt) = 8/15 sqrt(2 g) tg( alfa / 2)
Cd = 0.640 - 0.873 h1 + 5.101 h1^2 - 13.040 h1^3 + 12.311 h1^4
for alfa = 90
Cd = 0.637 - 0.566 h1 + 2.758 h1^2 - 6.425 h1^3 + 5.753 h1^4
for alfa = ½ 90
Cd = 0.612 - 1.288 h1 + 6.804 h1^2 - 16.686 h1^3 + 15.345 h1^4
for alfa = ¼ 90
Cd = 0.614 - 0.074 alfa + 0.046 alfa^2 - 0.009 alfa^3 for 20 <= alfa <= 100
(alfa in radians)
The following limitations apply on the use of the above formulae:
h1 <= htr
h1 <= 0.60 m and h2 <= -0.05 m
Q = Cg . Cd . b . H1^(3/2)
Cg = (2/3)^(3/2) sqrt(g)
Cd = 0.63
The following limitations apply on the use of the above formulae:
h1/b <= 0.5
h1 <= 0.6m and h2 <=-0.05m
Q = Cg . Cd . b . H1^(3/2)
Cg = sqrt(g)
Cd = 0.633
The modular limit h2/h1 = 0.75. If this value is exceeded a missing value will be entered for the discharge. Further limiting conditions are:
P >= 0.06 m
b >= 0.30 m
h1/P <= 3
b/h1 >= 2
For h1 <= htr :
Q = Cg . Cd . m . H1^(5/2)
Cg = 4/5 sqrt(g)
Cd = 0.615 for m <= 15
Cd = 0.620 for 15 < m < 30
Cd = 0.625 for m >= 30
m = b/2htr
For h1 > htr :
Q = Cg . Cd . m . (H1^(5/2) - (h1 - htr)^(5/2))
Cd = 0.620 for m <= 15
Cd = 0.625 for 15 < m < 30
Cd = 0.630 for m >= 30
The modular limit is:
for h1 <= htr h2/h1 = 0.70
for h1 > htr h2/h1 = 0.75
If the modular limit is exceeded a missing value will be entered for the discharge.