Surface wind flow modelling on Mars using Computational Fluid Dynamics

Wind flows on Mars are the dominant contemporary force driving sediment transport and associated morphological change on the planet’s dune fields. To fully understand the atmospheric – surface interactions occurring on the dunes, investigations need to be conducted at appropriate length scales (at or below that of any landform features being examined).

The spatial resolution of Martian Global Circulation Models (GCMs) is too low to adequately understand atmospheric-surface processes. Nevertheless, they can be utilised to establish initial state and boundary conditions for finer-scale simulations. Mesoscale atmospheric models have been used before to understand forcing and modification of entire dune fields. However, their resolution is still too coarse to fully understand interactions between the boundary layer and the surface. This study aims to examine and improve our understanding of local-scale processes using microscale (e.g., 1.5m cell spacing) airflow modelling to better investigate localised topographic effects on wind velocity and associated aeolian geomorphology.

Toward these aims, this study will simulate microscale wind flow using computational fluid dynamics software (OpenFOAM) at a series of sites containing a variety of topographies and wind regimes. A Mars GCM will provide input for baseline mesoscale modelling runs, the output of which will then be used as input for microscale airflow modelling. The sites used for the study will have excellent orbital, or preferentially, in situ data coverage. Detailed HiRISE imagery will provide high-resolution Digital Terrain Models (DTMs) which will be used by the OpenFOAM simulations. Results from model simulations will be evaluated/validated using both in situ data and geomorphic analysis of imagery.