WIND User's Guide - Keyword Reference, FIXER

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FIXER - Instability smoothing

FIXER [PRINT] [zone_selector]

WIND's FIXER capability searches for computational points at which there are negative values of density or internal energy (due to numerical instabilities) and replaces the faulty values with averages from nearby j and k points in the same i-plane. (I.e. the smoothing is two-dimensional; values from adjacent i-planes are not used.) The process is iterative, with multiple smoothing passes. Only "active" points are examined, not wall, coupled boundary, hole, or fringe points.

In a given i-plane, if more than 50% of the points are "bad", or if the smoothing process fails to remove all the negative values, the run is aborted.

Using FIXER may help the solution through difficult transients, but it may also simply smear out instabilities over a larger portion of the flowfield. You should maintain a careful watch over the solution.

For each i-plane containing negative values of density or internal energy, the zone, iteration number, i index, and number of "bad" points will be written to the list output (.lis) file. If the PRINT option is specified, the listing will also include the j and k indices of each "bad" point.