[CIG-SHORT] Fault strike not parallel with any axis gives small Jacobian error

[Brad Aagaard]

Birendra-

You have a bunch of nearly zero volume cells in your mesh. Note the 
number of cells with nearly zero aspect ratios listed as a result of the 
quality command when running LaGriT. This type of issue won't show up 
when you align the faults with the edges of the domain have have nice 
clean boxes with perpendicular sides. When you deviate from box type 
geometry, some cleanup of the mesh is usually necessary using LaGrit's 
mesh quality improvement routines (such as massage and reconnect). See 
the LaGriT documentation for details.

For nice simple geometry like you have, you should be able to get a mesh 
with a minimum aspect ratio of close to 0.4. Anything less than about 
0.2 or 0.3 will result in slow convergence in quasi-static problems.

Brad


On 10/9/10 9:02 PM, Birendra jha wrote:
> Dear Brad,
>
> I am trying to run the attached case and get RuntimeError:
> Determinant of Jacobian (3.73755e-07) for cell 11540 is smaller than
> minimum permissible value (1e-06)!
>
> When the faults strike parallel to y axis it runs fine.
>
> Another question: I am trying to find the source code that computes
> Jacobian matrix, for examples, for quasi-static problem (Sec 2.3 in
> Pylith manual). In particular I want to modify the linear elasticity
> Eq. (2.70) to include fluid pressure. Can you please help me in
> locating the file(s) that implements this?
>
> Thanks&  regards Birendra
>
>
>