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| Titel |
3D DSMC Modeling of the Inner Gas Coma of Comet 67P/Churyumov-Gerasimenko with an Unstructured Grid |
| VerfasserIn |
Ying Liao, Raphael Marschall, Cheng-Chin Su, Jong-Shinn Wu, Martin Rubin, Ian-Lin Lai, Wing-Huen Ip, Horst Uwe Keller, Joerg Knollenberg, Ekkehard Kuehrt, Yuri Skorov, Nicolas Thomas |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250105940
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| Publikation (Nr.) |
 EGU/EGU2015-5531.pdf |
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| Zusammenfassung |
| As the development of ESA’s Rosetta mission started, it became clear that the physics of the
outflow immediately above the surface needed to be understood. Ice sublimating from
nucleus surface into vacuum forms the Knudsen layer, which is a non-equilibrium boundary
layer with a scale height of about 20 mean free paths. In Rosetta’s orbit around Comet
67P/Churyumov-Gerasimenko (C-G), the mean free path will range from meters to
kilometers. Direct Simulation Monte Carlo (DSMC) is a very powerful numerical method to
study gas flows inside non-equilibrium regions and has been applied to study cometary
outflow by many authors over the past decade. The drawback with 3D DSMC is that it is
computationally highly intensive and thus time consuming. Our aim here is to determine the
gas flow-field in the innermost coma and to place constraints on the surface outgassing
properties from analysis of the flow-field. For a preliminary shape model of C-G, we have
identified to what extent modification of parameters influences the gas flow and temperature
fields and established the reliability of inferences about the initial conditions from in
situ and remote sensing measurements. The boundary conditions are implemented
with a publicly available nucleus shape model and thermal models based on the
surface heat balance equation. Several assumptions and different parameter sets have
been investigated by DSMC runs using the PDSC++ (Parallel Direct Simulation
Monte Carlo) code on an unstructured tetrahedral grid. In this work, we will present
simulations of the flow field and changes resulting from modification of specific variables. |
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