MAST solution of advection problems in irrotational flow fields

A new numerical-analytical Eulerian procedure is proposed for the solution of convection dominated problems in the case of existing scalar potential of the flow field. The methodology is based on the conservation inside each computational elements of the 0th and 1st order effective spatial moments of the advected variable. This leads to a set of small ODE systems solved sequentially, one element after the other over all the computational domain, according to a MArching in Space and Time technique. The proposed procedure shows the following advantages: 1) it guarantees the local and global mass balance; 2) it is unconditionally stable with respect to the Courant number, 3) the solution in each cell needs information only from the upstream cells and does not require wider and wider stencils as in most of the recently proposed higher order methods; 4) it provides a monotone solution. Several 1D and 2D numerical test have been performed and results have been compared with analytical solutions, as well as with results provided by other recent numerical methods