Large-scale turbulence modelling via α-regularisation for atmospheric simulations

Abstract

We study the possibility of obtaining a computational turbulence model by means of non-dissipative regularisation of the compressible atmospheric equations for climate-type applications. We use an α-regularisation (Lagrangian averaging) of the atmospheric equations. For the hydrostatic and compressible atmospheric equations discretised using a finite volume method on unstructured grids, deterministic and non-deterministic numerical experiments are conducted to compare the individual solutions and the statistics of the regularised equations to those of the original model. The impact of the regularisation parameter is investigated. Our results confirm the principal compatibility of α-regularisation with atmospheric dynamics and encourage further investigations within atmospheric model including complex physical parametrisations.

Keywords:

• hydrostatic atmosphere
• non-dissipative regularisations
• Lagrangian-averaged equations

Acknowledgements

We would also like to acknowledge generous help of Dr. H. Wan with the ICON hydrostatic atmosphere model.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. The Navier–Stokes-α equations also appear in the literature under the name ‘Lagrangian-averaged Navier–Stokes-α’ or ‘viscous Camassa–Holm equations’.

Additional information

Funding

This project is supported in part by DFG SPP 1276 Metstroem program.