This is a straight pipe with constant section and head losses
defined by the formula:
![]() |
(15) |
where f is the White-Colebrook coefficient (dimensionless), is the
mass flux, L is the length of the pipe, g is the gravity
acceleration (
m
s
), A is the cross section of the pipe
and D is the diameter. The White-Colebrook coefficient satisfies the
following implicit equation:
![]() |
(16) |
Here, is the diameter of the material grains at the surface of the pipe
and Re is the Reynolds number defined by
Re![]() |
(17) |
where is the liquid velocity and
is the kinematic viscosity. It
satisfies
where
is the dynamic viscosity.
The following constants have to be specified on the line beneath the *FLUID SECTION, TYPE=PIPE WHITE-COLEBROOK card):
The length of the pipe is determined from the coordinates of its end nodes,
the gravity acceleration must be specified by a gravity type
*DLOAD card defined for the elements at stake. The material
characteristics and
can be defined by a
*DENSITY and *FLUID CONSTANTS
card. Typical values for
are 0.25 mm for cast iron, 0.1 mm for welded
steel, 1.2 mm for concrete, 0.006 mm for copper and 0.003 mm for glass.