UFLUIDPIPEFRICTION

User subroutine to define the frictional coefficient for fluid flow in fluid pipe elements.

can be used to define the frictional coefficient for fluid flow to determine the pipe loss;
corresponds to the Darcy-Weisbach equation for pressure loss; and
can be used with the fluid pipe elements.

The following topics are discussed:

User subroutine interface
Variables to be defined
Variables passed in for information

User subroutine interface

      subroutine ufluidpipefriction (
C Write only - 
     *   friction
C Read only - 
     *   flow, rho, visc, rough, 
     *   dia, area, 
     *   ndim, jelno, kstep, kinc, 
     *   time, coords,
     *   niarray,
     *   i_array,
     *   nrarray,
     *   r_array,
     *   ncarray,
     *   c_array)
      include 'aba_param.inc'
C
      dimension time(2), 
     *   coords(2*ndim),
     *   i_array(niarray),
     *   r_array(nrarray)
C
      character*80 c_array(ncarray)
C
      user coding to define friction
      return
      end

Variables to be defined

friction: This value must be updated to the current value of the friction coefficient.

Variables passed in for information

flow: Current flow rate through the element.
rho: Current density of fluid flowing through the pipe.
visc: Current viscosity of fluid flowing through the pipe.
rough: User-specified pipe roughness.
dia: User-specified hydraulic diameter.
area: User-specified hydraulic area.
ndim: Dimension of the element.
jelno: User element number for which friction coefficient is required.
kstep: Step number.
kinc: Increment number.
time(1): Current step time.
time(2): Total time.
coords(2*ndim): Array containing original coordinates of the element. coords(1:ndim) is the coordinate of the first node, and coords(ndim+1:2*ndim) is the coordinate of the second node.
niarray: Size of array i_array.
i_array: Integer array for future expansion.
nrarray: Size of array r_array.
r_array: Real array for future expansion.
ncarray: Size of array c_array.
c_array: Character array for future expansion.