FLOW

User subroutine to define nonuniform seepage coefficient and associated sink pore pressure for consolidation analysis.

User subroutine FLOW:

  • can be used in a soils consolidation analysis to define the variation of the reference pore pressure and the seepage coefficient as functions of position, time, pore pressure, element number, integration point number, etc.;

  • will be called at each integration point of element surfaces for which element-based or surface-based nonuniform surface seepage flow is defined; and

  • ignores any amplitude references that may appear with the associated nonuniform flow definition.

The following topics are discussed:

Related Topics
In Other Guides
Pore fluid flow
*FLOW
*SFLOW

ProductsAbaqus/Standard

User subroutine interface

      SUBROUTINE FLOW(H,SINK,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 H and SINK


      RETURN
      END

Variables to be defined

H

Seepage coefficient at this point. Units are F−1L3T−1. H will be passed into the routine as the reference seepage coefficient value specified as part of the element-based or surface-based flow definition. If the reference value is not defined, H will be passed in as zero.

SINK

Sink pore pressure. SINK will be passed into the routine as the reference pore pressure value specified as part of the element-based or surface-based flow definition. If the reference value is not defined, SINK will be passed in as zero.

Variables passed in for information

U

Estimated surface total pore pressure at this time and 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

Surface integration point number.

COORDS

An array containing the coordinates of this integration 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 FLOW is being made for an element-based flow. This information is useful when several nonuniform flow conditions are being imposed on an element at the same time. See About the element library for identification of the element faces. The key is as follows:

JLTYP Flow type
0  Surface-based flow
61 Q1NU
62 Q2NU
63 Q3NU
64 Q4NU
65 Q5NU
66 Q6NU
SNAME

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