  Infrasound monitoring has proved to be effective in detection of the meteor
generated shock waves. When combined with optical observations of meteors, this
technique is also reliable for detecting centimeter-sized meteoroids that
usually ablate at high altitudes, thus offering relevant clues that open the
exploration of the meteoroid flight regimes. Since a shock wave is formed as a
result of a passage of the meteoroid through the atmosphere, the knowledge of
the physical parameters of the surrounding gas around the meteoroid surface can
be used to determine the meteor flow regime. This study analyses the flow
regimes of a data set of twenty-four centimeter-sized meteoroids for which well
constrained infrasound and photometric information is available. This is the
first time that the flow regimes for meteoroids in this size range are
validated from observations. From our approach, the Knudsen and Reynolds
numbers are calculated, and two different flow regime evaluation approaches are
compared in order to validate the theoretical formulation. The results
demonstrate that a combination of fluid dynamic dimensionless parameters is
needed to allow a better inclusion of the local physical processes of the
phenomena.
