element_data, a FORTRAN77 code which preprocesses simple element-based data on a grid into a form that the DISPLAY4 code can handle.
A set of nodes are specified in a region, and groups of 4 nodes comprise elements. At each node, a set of physical quantities is given, in particular, the X and Y coordinates, the fluid pressure P, and the horizontal and vertical flow velocity components U and V. This information has been written into a file. That information must be reformatted to work with DISPLAY4.
Specifically, for each node, there is at least one line of the form:
X Y P PSI U V W
where PSI (presumably the stream function) and W (the magnitude of
(U,V)) are not of interest to us.
Each element is represented by listing the nodes that comprise it, with the initial node repeated at the end, followed by a blank line. All elements in the current data set comprise 4 nodes. Thus, the information defining one element would be the central lines of the following:
(previous element just finishing up)
X1 Y1 P1 PSI1 U1 V1 W1
X1 Y1 P1 PSI1 U1 V1 W1
X2 Y2 P2 PSI2 U2 V2 W2
X3 Y3 P3 PSI3 U3 V3 W3
X4 Y4 P4 PSI4 U4 V4 W4
X1 Y1 P1 PSI1 U1 V1 W1
X1 Y1 P1 PSI1 U1 V1 W1
(New element being defined)
DISPLAY4, on the other hand, expects two data files, a node data file, which lists each node once, and the properties U, V, and P:
X Y U V P
which implicitly assigns an index to each node,
and an element data file, which lists the number of elements,
the number of nodes per element, and then, for each element, the
node indices related to the element:
1024
4
N1 N2 N3 N4
N1 N2 N3 N4
...
...(1024 records like this)
...
N1 N2 N3 N4
The code reads the old data, counts items, discards duplicate node information, and writes out the two data files needed by DISPLAY4.
The name of the input file is usually specified on the command line:
element_data input_file
The output files are always named element.txt and node.txt.
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
element_data is available in a FORTRAN77 version.
contour, a FORTRAN90 program which reads a file of combined coordinate and attribute data for points on a rectangular grid, and extracts the node and element geometry information for input to DISPLAY3.
DISPLAY4, a FORTRAN90 program which displays graphics from the flow data computed by FLOW3, FLOW5 or FLOW7. This program used to work, but it is very out of date;
FLOW3 is a FORTRAN90 program which solves the 2D steady incompressible Navier Stokes equations using the finite element method.
FLOW4 is a FORTRAN90 program which solves the 2D steady incompressible Navier Stokes equations using the finite element method.
FLOW5 is a FORTRAN90 program which solves the 2D steady incompressible Navier Stokes equations using the finite element method.
FLOW6 is a FORTRAN90 program which solves the 2D steady incompressible Navier Stokes equations using the finite element method.
FLOW7 is a FORTRAN90 program which solves the 2D steady incompressible Navier Stokes equations using the finite element method.