This study focuses on the numerical analysis of large meteoroids during their entry into Earth atmosphere. For this purpose, two entries of meteoroids have been computed: the Chelyabinsk event that occurred in 2013, and a meteor, which felt in the Atlantic Ocean in February 2016, the Saint-Valentine day. For both meteoroids, several points along their re-entry trajectory have been calculation. Computations have been then performed using a non-equilibrium Navier-Stokes solver to determine the temperatures and the composition of the mixture around the meteoroids, as well as the convective heating.
Then, the SPARK line-by-line radiation code has been selected to post-process the CFD results for predicting the radiative heating. It has to be noted that SPARK capabilities have been recently extended via an updated database capable of reproducing VUV molecular radiation. The spectra obtained for the St Valentine meteoroid, highlight the strong contribution of molecular VUV radiation at high altitude. Then, comparisons have been carried out between the radiative heating calculated using engineering correlations and the CFD/radiation computations at the different altitudes. The comparison put in evidence the lack of reliability of usual stagnation point correlations particularly at low altitude and high level of stagnation pressure.
Finally, the last part of this work focuses on the meteoroid demise. Firstly, a qualitative analysis of the thermal response of the meteoroid accounting for the available elements convective and radiative blockage have been conducted. In a last step, an estimate of the material opacity for the incoming radiation wavelength range has been performed based on the available literature on silica materials. A scenario for the meteoroid demise is then proposed, supported by the outcome of this work.
