PETSc interface for staggered and structured grid?

[Etienne Ahusborde]

Hello,

I am a new user of PETSc.

My goal is to solve linear systems coming from the Navier-Stokes 
equations. Components of the velocity field
are coupled each other, so that, in 2D, the matrix is composed of four 
blocks (two diagonal blocks, one for each component,
and two extra-diagonal blocks for the coupling between u and v). 
Discretization is made on a staggered and structured grid
(MAC grid, one grid for each component).

After having read the user manual, I an wondering if there is a way to 
take benefit of the structured grid as the Semi-Structured-Grid 
System interface of Hypre, or if I have to use the parallel AIJ Sparse 
matrices. We have understood that the distributed arrays are
rather  adapted to scalar equations (in comparison with coupled 
vectorial equations).

In your opinion, what is the best way to treat our problem?

Kind regards

Etienne Ahusborde