Rectangular channel · sluice-gate control, GVF and hydraulic jump
Flow and roughness
m³/s
m
In SI units, , the inverse of Strickler’s coefficient.
Upstream reach
A contracted jet forms when and . An upstream M1 profile is required only when ; otherwise the upstream flow remains at normal depth and loses the excess energy at the contraction.
Sluice gate
m
The gate controls the upstream reach only when . The contracted-jet depth is .
Downstream reach
The downstream boundary is . For , the jump regime follows the comparison between and . A supercritical normal depth produces an S2 or S3 profile without a jump.
Show
Read the flume from left to right: the M1 profile reaches the gate, the jet contracts, and the downstream force comparison produces a drowned jump, a jump at the vena contracta, or a schematically displaced jump. If , an S2/S3 profile reaches normal flow without a jump.
Upstream gate checks
Channel width
Gate opening
Upstream normal depth
Vena-contracta condition
M1 energy residual
CHECKING GATE CONTROL
Control depths
Depth at the gate
Vena-contracta depth
Critical depth
Downstream normal depth
Gate and specific energy
Discharge per width
Jet velocity
Jet Froude number
Gate specific energy
Downstream adjustment
Normal-flow Froude
Vena specific force
Tailwater specific force
Downstream profile
Jet depth at jump
Conjugate depth
Jump energy loss
DOWNSTREAM NORMAL FLOW
For a pushed jump, its displayed location is deliberately schematic. The pre-jump depth is calculated from ; the connecting M3 profile is obtained from the gradually varied flow equation. The interface treats forces within 1.5% as the immediate-jump equality case.
Upstream normal Gate Vena Critical Downstream normal Pre-jump Conjugate