CFD matrices from Francois Pacull, FLUOREM, in Lyon, France We are dealing with CFD and more precisely steady flow parametrization. The equations involved are the compressible Navier-Stokes ones (RANS). These matrices are real, square and indefinite, they correspond to the Jacobian with respect the conservative fluid variables of the discretized governing equations (finite-volume discretization). Thus they have a block structure (corresponding to the mesh nodes: the block size is the number of variables per mesh node), they are not symmetric (however, their blockwise structure has a high level of symmetry) and they often show some kind of hyperbolic behavior. They have not been scaled or reordered. They are generated through automatic differentiation of the flow solver around a steady state. A right hand-side is also given for each matrix: this represents the derivative of the equations with respect to a parameter (of operation or shape). Since they are generated automatically, they may have "silent" variables: these are variables corresponding to an identity submatrix associated with a null right hand-side, for example one of the three velocity components in a 2D case, or the turbulent variables in a "frozen" turbulence case. We believe that these matrices are good test cases when studying preconditioning methods for iterative methods, such as block incomplete factorization, or when studying domain decomposition methods or deflation. They are actually being studied by a few researchers in France regarding numerical methods, through the LIBRAERO research project of the ANR (national research agency): ANR-07-TLOG-011. Francois Pacull, Lyon, France. fpacull at fluorem.com Reference: "A Study of ILU Factorization for Schwartz Preconditioners with Application to Computational Fluid Dynamics", F. Pacull, S. Aubert, M. Buisson, Proceedings of the 2nd Intl Conf on Parallel, Distributed, Grid, and Cloud Computing for Engineering, B.H.V Topping and P. Iva'nyi, Editors. Civil-Comp Press, Stirlingshire, Scotland, 2011. Specific problem descriptions: DK01R: 1D turbulent case number of mesh nodes: 129 block size: 7 variables: [rho,rho*u,rho*v,rho*w,rho*E,rho*k,rho*omega] (rho v and rho w are "silent", the third and fourth rows and columns in each block can be removed) matrix order: 903 nnz: 11766 comments: The DK01R matrix corresponds to a small 1D turbulent case. The grid has 129 nodes, non-uniformly spaced (geometrical distribution). The number of unknowns per node is 7, leading to a linear system of 903 real algebraic equations. The 1D discretization of the partial differential equations uses a 5 points stencil, leading to a block penta-diagonal matrix, each block having size 7 by 7. Each diagonal block is related to two up- and two down-stream neighboring nodes, corresponding respectively to the 14 upper and 14 lower matrix rows, the node ordering being coherent with the 1D spatial node distribution. The stationary flow on which the matrix is based on is dominated by advection, characterized by a Mach number around 0.3. GT01R: 2D inviscid case number of mesh nodes: 1596 block size: 5 variables: [rho,rho*u,rho*v,rho*w,rho*E] (rho w is "silent", the fourth row and column in each block can be removed) matrix order: 7980 nnz: 430909 comments: This is a 2D linear cascade turbine case. The grid corresponds to one inter-blade channel. The stencil involved by the convective scheme uses 9 nodes. Thus, there are 9 non-zero blocks for each node in the matrix. The specificity is that the computational domain is periodic, which introduces some non-zeros elements far away from the diagonal. PR02R: 2D turbulent case number of mesh nodes: 23010 block size: 7 variables: [rho,rho*u,rho*v,rho*w,rho*E,rho*k,rho*omega] (rho v is "silent", the third row and column in each block can be removed) matrix order: 161070 nnz: 8185136 comments: This is a 2D turbulent case, dominated by convection. The geometry is a RAE wing profile and the mesh is C-shaped. RM07R: 3D viscous case with "frozen" turbulence number of mesh nodes: 54527 block size: 7 variables: [rho,rho*u,rho*v,rho*w,rho*E,rho*k,rho*omega] (rho k and rho omega are "silent", the sixth and seventh rows and columns in each block can be removed) matrix order: 381689 nnz: 37464962 comments: The geometry is a jet engine compressor. HV15R: 3D engine fan. The flow has a low Mach number. This is a 3D Reynolds-Averaged-Navier-Stokes case. Number of mesh nodes: 288,167 block size: 7 variables: [rho, rho*u, rho*v, rho*w, rho*E, rho*k, rho*omega] matrix order: 2,017,169 nnz: 283,073,458