1. HYDROGRID J. Erhel – October 2004 Components and grids  Deployment of components  CORBA model  Parallel components with GridCCM Homogeneous cluster Mechanics Flow Transport Chemistry Thermodynamics Homogeneous cluster

2. HYDROGRID J. Erhel – October 2004 Applications in hydrogeology  Coupled physical models  One model = one software = one component  Parallel programs = parallel components  Saltwater intrusion : flow / transport  Reactive transport : transport / chemistry  Coupled computational domains  Network of fractures : 2D fracture / 3D network  Fractured media : porous media / fractures

3. HYDROGRID J. Erhel – October 2004 Components and applications Chemistry component Flow component Transport component Reactive transport Saltwater intrusion

4. HYDROGRID J. Erhel – October 2004 Flow Transport time t = 0 t = Δt control iterative scheme at each timestep Numerical coupling in saltwater intrusion

5. HYDROGRID J. Erhel – October 2004 Components for saltwater Intrusion Flow component Transport component Controller component velocity scalars concentration

6. HYDROGRID J. Erhel – October 2004 Chemistry Transport 1 time t = 0 t = Δt control Transport N Iterative scheme at each timestep N species Numerical coupling in reactive transport …..

7. HYDROGRID J. Erhel – October 2004 Transport component Components for reactive transport Chemistry component concentrations Controller component Transport component Transport component Transport component Transport component

8. HYDROGRID J. Erhel – October 2004 Transport and flow components  Density computation  Flow matrix and right-hand side computation  Sparse linear solver  Velocity computation Flow component Transport component  Explicit convection operator  Diffusion matrix and right- hand side computation  Sparse linear solver  Flux limiter

9. HYDROGRID J. Erhel – October 2004 Direct versus iterative linear solver Mesh size 64x40

10. HYDROGRID J. Erhel – October 2004 System size order(A) = nonzeros(A) = O(n) nonzeros(LU) = O(n 1.1 )

11. HYDROGRID J. Erhel – October 2004 Sequential CPU times Mesh size n = 40 000 One time-step about 100 seconds 900 time steps about 25 hours Linear solver = O(n 1.1 ) Each step must be parallel Pentium III, 512 MB

12. HYDROGRID J. Erhel – October 2004 Parallel sparse linear solver MUMPS solver Different renumberings Bi-processor Itanium cluster Myrinet network Mesh size = 254x126 – matrix order about 64 000

13. HYDROGRID J. Erhel – October 2004 Parallel components : subdomain approach  Same partition in flow and transport  METIS with MUMPS

14. HYDROGRID J. Erhel – October 2004 Fracture network Equations Q = - K.  h Div ( Q ) = 0 Boundary conditions Head fixed Dirichlet (Q.n = 0) Neumann

15. HYDROGRID J. Erhel – October 2004 Software  Network generation  Network discretisation  Mesh of each fracture (Emc2)  Global numbering  Matrix and right-hand-side computation (modified procedures of Traces)  Sparse linear solver (UMFPACK)  Subdomain approach