Meshing Tutorial 1>INTRODUCTION Meshing Tutorial 1>RJUMP MESHER 


ELEMENT-SIZE ASSIGNMENT METHODS

GiD automatically corrects element sizes according to the shape of the entity to be meshed and its surrounding entities. This default option may be deactivated and reactivated by going to the Mesh menu, selecting Preferences , and then Automatic correct sizes .

Footnote: The Preferences option can also be found in the Utilities menu.

Footnote: Automatic correct sizes automatically executes the options Assign sizesBy geometry and Assign sizesCorrect sizes .

Sometimes, however, this type of correction is not sufficient and it is necessary to indicate where on the mesh greater accuracy is needed. In these cases, GiD offers various options and methods allowing sizes to be assigned to elements.

Five examples are shown to illustrate the default method and the four other methods.

Assignment using default options

Figure 2. Meshing by default.

Note that in the zone highlighted in Figure 3, elements are smaller than in the rest of the model. This is because of the shape of the surface placed there. When all meshing preferences are set to their default levels, as for this example, the RFAST surface mesher is used. In this way, geometrical entities are meshed hierarchically: first of all lines are meshed, then the surfaces, and finally the volumes. The line elements size depends on the shape of surfaces (as can be seen in this example). Later on we will see an example using RJUMP mesher, where element sizes are distributed differently.

Figure 3. Meshing by default. Zone where elements are smaller because of the surface shape.

Assignment around points

Footnote: Instead of pressing the ESC key, the center mouse button or the mouse wheel can also be used.

Figure 4. Geometry of the model. The point around which the mesh will be concentrated.

Figure 5. The mesh with a concentration of elements around the point.

Figure 6. Mesh with the elements concentrated around a point, with a size gradient of 0.8.

Assignment around lines

Figure 7. Mesh with a concentration of elements around lines.

Assignment on surfaces

Figure 8. Mesh with a concentration of elements on a surface.

Assignment with Maximum Chordal Error

Figure 9. Mesh using sizes assignment by chordal error. Here, there is a greater concentration of elements in the curved zones.


 Meshing Tutorial 1>INTRODUCTION Meshing Tutorial 1>RJUMP MESHER