Inside the polygon defined by the closed boundary contour the nodes are generated by the following principle:
0th step:
Step 0 generates one node at each of the contour points, the start and end points of contour lines and the division points between them.
The following steps generate nodes along contour lines:
At segmentation points of contour lines the algorithm produces a node normal to the line.
At start and end points of contour lines without adjacent lines the nodes are generated at 90, 150, 210 and 270 degrees to the contour line.
At start and end points of contour lines which are continued by another contour line the algorithm generates nodes depending on the angle between the two lines. For an angle between 90 and 180 degrees, the nodes are generated along the centre of the angle. If the angle is larger than 270 degrees, the algorithm produces nodes normal to each of the contour lines.
The distance between the contour line and the new node is calculated from the average distance "dist" between the corresponding node and its two adjacent nodes on the contour line:
For the case of standard contour lines (l-contour) step n of the boundary node generator generates nodes with at a distance of n*dist from the contour line.
Boundary node generator for l-contours (step 1)
For the case of contour lines which represent fractures (k-contour lines) step n generates one node at a distance of n*fakt*dist from the contour line. The scaling factor fakt (length factor) is an individual parameter and can be defined by the user. Finally, the algorithm automatically generates nodes between the node on the contour line and the new one. The distances between them increase exponentially.
Boundary node generator for k-contours (step 2, fakt = 0,8)
Further steps generate nodes at 45, 90, 135, 180, 225, 270 and 315 degree around contour points which represent wells with the corresponding parameters (Ri, Ra and C>0). The distance is calculated from R_n = Ri * Cn.
Starting with an initial, final or division node, the node-generation algorithm continues to generate nodes until one of the following criteria is fulfilled:
The distance reaches the defined limit
n*dist in the case of contour lines (l-contour lines),
n*fakt*dist in the case of contour fracture lines (k-contour lines) and
maximum outer radius Ra in the case of contour nodes with parameters for wells, or
there is already a mesh node near the node to be generated, or
the distance between another contour line and the node to be generated is too short, or
the node to be generated would be out of the model area. Into this direction the algorithm will not generate any further nodes.
Algorithm of the grid node generator