DFLOW

User subroutine to define nonuniform pore fluid velocity in a consolidation analysis.

User subroutine DFLOW:

can be used to define the variation of the seepage magnitude as a function of position, time, pore pressure, etc. in a soils consolidation analysis;
will be called at each flow integration point for each element-based or surface-based nonuniform flow definition in the analysis; and
ignores any amplitude references that may appear with the associated nonuniform flow definition.

The following topics are discussed:

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

User subroutine interface

      SUBROUTINE DFLOW(FLOW,U,KSTEP,KINC,TIME,NOEL,NPT,COORDS,
     1 JLTYP,SNAME)
C
      INCLUDE 'ABA_PARAM.INC'
C
      DIMENSION TIME(2),COORDS(3)
      CHARACTER*80 SNAME


      user coding to define FLOW


      RETURN
      END

Variables to be defined

FLOW

Effective velocity of pore fluid crossing the surface at this point from the inside of the region modeled to the outside of the region modeled. Units are LT⁻¹. Effective velocity is the volumetric flow rate per unit area (refer to Permeability).

FLOW will be passed into the routine as the magnitude of the seepage specified as part of the element-based or surface-based flow definition. If the magnitude is not defined, FLOW will be passed in as zero.

The effective velocity is not available for output purposes.

Variables passed in for information

U

Estimated pore pressure at this time at this point.

KSTEP

Step number.

KINC

Increment number.

TIME(1)

Current value of step time (defined only in transient analysis).

TIME(2)

Current value of total time (defined only in transient analysis).

NOEL

Element number.

NPT

Integration point number on the element's surface.

COORDS

An array containing the coordinates of this point. These are the current coordinates if geometric nonlinearity is accounted for during the step (see Defining an analysis); otherwise, the array contains the original coordinates of the point.

JLTYP

Identifies the element face for which this call to DFLOW is being made through the element-based flow definition. This information is useful when several different nonuniform distributed flows are being imposed on an element at the same time. See About the element library for identification of element faces. The key is as follows:

JLTYP	Flow type
0	Surface-based load
11	S1NU
12	S2NU
13	S3NU
14	S4NU
15	S5NU
16	S6NU

SNAME

Surface name for which this call to DFLOW is being made through the surface-based flow definition (JLTYP=0). For an element-based flow definition the surface name is passed in as a blank.