Turbulence Models for Titan Exploration
- JHU Applied Physics Lab, Space Department, Laurel, United States of America (ralph.lorenz@jhuapl.edu)
Engineering development of future Titan missions demands a specification of winds and gusts. Despite the very austere Huygens data on which to base such a specification, fundamental scaling principles allow the adaptation of empirical terrestrial descriptions for both discrete gusts and continuous turbulence. The principal factors driving these are the mean wind, the depth of the planetary boundary layer, and convective forcing : in the absence of strong mean wind, the gusts are driven by thermal vortices ('dust devils') which have a thermodynamic limit.
A succinct formulation of turbulence, yielding a Dryden spectrum (-2 power law) is developed with a random-walk (AR(1)) model, that can be implemented with a few lines of code (Lorenz, R., Planetary and Space Science, 214, 105459. https://doi.org/10.1016/j.pss.2022.105459). This spectrum is nearly the same as the Von Karman/Kolmogorov (-5/3 power law).
The history of turbulence specifications, and the models being developed for Dragonfly and for an update to the Titan-GRAM statistical modeling package, and their validation with in-situ data, are described.
How to cite: Lorenz, R.: Turbulence Models for Titan Exploration, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-452, https://doi.org/10.5194/epsc2022-452, 2022.