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Pipe, Manning

This is a straight pipe with constant section and head losses $ \Delta_1^2 F$ defined by the Manning formula:

$\displaystyle \Delta_1^2 F = \frac{n^2 \dot{m}^2 L}{\rho^2 A^2 \mathcal{R}^{4/3}},$ (14)

where n is the Manning coefficient (unit: time$ /$   length$ ^{1/3}$), $ \dot{m}$ is the mass flux, L is the length of the pipe, $ \rho$ is the liquid density, A is the cross section of the pipe and $ \mathcal{R}$ is the hydraulic radius defined by the area of the cross section divided by its circumference (for a circle the hydraulic radius is one fourth of the diameter). The following constants have to be specified on the line beneath the *FLUID SECTION, TYPE=PIPE MANNING card):

The length of the pipe is determined from the coordinates of its end nodes. Typical values for $ n$ are $ n=0.013$   s$ /$m$ ^{1/3}$ for steel pipes and $ n=0.015$   s$ /$m$ ^{1/3}$ for smooth concrete pipes.



guido dhondt 2007-02-18