Aerothermodynamic modelling of meteor entry flows in the rarefied regime

Federico Bariselli, Stefano Boccelli, Thierry Magin, Aldo Frezzotti, Annick Hubin

Onderzoeksoutput: Conference paper

1 Citaat (Scopus)


Due to their small size and tremendous speeds, meteoroids often burn up at high altitudes, above 80 km, where the atmosphere is rarefied. Ground radio stations are able to detect the free electrons concentration in the meteoroid wake, which is produced by hyperthermal collisions of the ablated species with the free-stream. The interpretation of radio data, however, currently relies on phenomenological methods, derived under the assumption of free molecular flow, hence, poorly accounts for the dynamics of the vapour, chemistry, and diffusion in the meteor trail. In this work, we aim to provide a detailed description of the flowfield around a meteoroid by means of Direct Simulation Monte Carlo and to obtain the evolution of the free electrons in the meteor wake via an extended trail simulation. An evaporation boundary condition is developed in the framework of an open source DSMC software. The material is assumed to be composed by a mixture of metal oxides which are typically present in ordinary chondritic meteorites. The transport properties of the ablated vapour are computed following the Chapman-Enskog theory and the DSMC phenomenological parameters are retrieved by fitting the collision integrals over a wide range of temperatures. As a last step, chemical and diffusion processes in the trail are computed. Starting from the baseline DSMC solution, our approach marches in time along the precomputed streamlines, calculating chemistry and radial diffusion for metals and free electrons. As study case, the flow around a 1 mm evaporating meteoroid is analysed at different altitudes. A high level of thermal nonequilibrium is appreciated in the head of the meteor, whereas in the trail, after a few diameters, the flow equi-librates. At lower densities, the vapour can travel upstream without interacting much with the incoming jet. On the other hand, at lower altitudes, re-condensation plays a significant role in the stagnation region. Finally, a trail, several meters long and formed by metallic species, generates behind the body. Ionization of sodium turns out to be the dominant process in the production of free electrons, whereas radial diffusion seems to prevail over recombination as depletion mechanism.

Originele taal-2English
Titel2018 Joint Thermophysics and Heat Transfer Conference
UitgeverijAmerican Institute of Aeronautics and Astronautics Inc. (AIAA)
Aantal pagina's23
ISBN van geprinte versie9781624105524
StatusPublished - 1 jan 2018
Evenement12th AIAA/ASME Joint Thermophysics and Heat Transfer Conference, 2018 - [state] GA, United States
Duur: 25 jun 201829 jun 2018


Conference12th AIAA/ASME Joint Thermophysics and Heat Transfer Conference, 2018
LandUnited States
Stad[state] GA


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