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The momentum equation for open-channel flow may be found by starting from the incompressible Navier-Stokes equations : ⏟ + ⏟ ⏞ = ⏟ + ⏟ ⏟ + ⏟ where is the pressure, is the kinematic viscosity, is the Laplace operator, and = is the gravitational potential.
The extended Froude number is defined as the ratio between the kinetic and the potential energy: = + (), where u is the mean flow velocity, β = gK cos ζ, (K is the earth pressure coefficient, ζ is the slope), s g = g sin ζ, x is the channel downslope position and is the distance from the point of the mass release along the channel to the ...
The energy equation used for open channel flow computations is a ... subcritical” and have a Froude Number less than 1, while depths less than critical depth are ...
To help visualize the relationship of the upstream Froude number and the flow depth downstream of the hydraulic jump, it is helpful to plot y 2 /y 1 versus the upstream Froude Number, Fr 1. (Figure 8) The value of y 2 /y 1 is a ratio of depths that represent a dimensionless jump height; for example, if y 2 /y 1 = 2, then the jump doubles the ...
ASTM D1941 – 91(2013) Standard Test Method for Open Channel Flow Measurement of Water with the Parshall Flume; ISO 9826:1992 Measurement of Liquid Flow in Open Channels – Parshall and SANIIRI Flumes; JIS B7553-1993 Parshall Flume Type Flowmeters; Bos, Marinus (1989). Discharge Measurement Structures. Third edition revised. Publication 20 ...
Amount upstream flow is supercritical (i.e., prejump Froude Number) Ratio of height after to height before jump Descriptive characteristics of jump Fraction of energy dissipated by jump [11] ≤ 1.0: 1.0: No jump; flow must be supercritical for jump to occur: none 1.0–1.7: 1.0–2.0: Standing or undulating wave < 5% 1.7–2.5: 2.0–3.1
For flow in a pipe of diameter D, experimental observations show that for "fully developed" flow, [n 2] laminar flow occurs when Re D < 2300 and turbulent flow occurs when Re D > 2900. [ 15 ] [ 16 ] At the lower end of this range, a continuous turbulent-flow will form, but only at a very long distance from the inlet of the pipe.
Open channel flow describes cases where flowing liquid has a top surface open to the air; the cross-section of the flow is only determined by the shape of the channel on the lower side, and is variable depending on the depth of liquid in the channel. Techniques appropriate for a fixed cross-section of flow in a pipe are not useful in open channels.