3D Numerical Modelling of a Rarefied Gas Flow in the Nearby Atmosphere around a Rotating Cometary Nucleus

Abstract

A combined 3D model of a nearby atmosphere around an arbitrary rotating spherical cometary nucleus is developed. The model includes a 3D unsteady model of solar radiation absorption and heating of the nucleus material (water ice), its evaporation and condensation and a 3D quasi-stationary kinetic model of flow inside the near nucleus coma. This model can be used to predict the coma flow in conditions typical for rendezvous projects such as ESA project Rossetta. Calculations are carried out with the help of this model to reveal the influence of nucleus rotation on its temperature field and the flow field in the nearby atmosphere. It was found that the nucleus rotation influences significantly the nucleus temperature field and the coma flow. Vapor flow around a rotating nucleus is essentially three dimensional and differs qualitatively from the coma flow around a non-rotating nucleus.