TITAN'S CHANNELS: VELOCITY DISTRIBUTIONS, SEDIMENT TRANSPORT AND EROSIONAL IMPLICATIONS

The Cassini Huygens mission to Titan, Saturn’s largest moon, has documented an active alkanologic cycle for the circulation, precipitation, and runoff of alkanes (i.e. hydrocarbons, primarily methane) that parallels Earth’s hydrologic cycle with similar geomorphologic results. The Huygens Descent Imager/Spectral Radiometer showed drainage networks as well as rounded to subrounded surface clasts. Like on Earth, Titan’s precipitation apparently produces overland flow, subsurface flow, and channel flow, and multiple morphologic types of channels have been observed. This study considers computational fluid dynamics simulations of methane channel flow under Titan conditions for several channel geometries and flow conditions (laminar, transitional, turbulent), and evaluates potential sediment transport from the velocity distributions and particle tracing on both bedrock (water ice) and unconsolidated (sediment) beds. Preliminary results suggest that particle transport on less consolidated materials loses saltation load energy to the channel walls, but the suspension load is primarily dependent on the velocity distribution and material viscosity. Additional constraints on the material properties of methane/ethane under Titan conditions with and without sediment loads would better constrain the maximum clast size conditions.