Abstract
Stochastic subgrid turbulence parameterisations are developed for a baroclinic quasi-geostropic (QG) atmosphere with a January background state and realistic topography. The parameterisation coefficients are calculated from the statistics of higher resolution reference direct numerical simulations (DNS). Separate parameterisations are developed for each of the fundamental subgrid interactions. The first are the transient eddy-eddy interactions, which are between subgrid and resolved eddies. The second are the eddy-meanfield interactions between the subgrid eddies and the resolved meanfield. The third are the meanfield-meanfield interactions between the resolved meanfield and topography and their unresolved counterparts. Finally the eddy-topographic interactions are between the subgrid eddies and the resolved topography. This parameterisation framework is validated by producing large eddy simulations (LES) of the atmosphere that agree with the reference DNS. As compared to the DNS of truncation wavenumber 63, successful LES are produced with a truncation wavenumber of 15, using only 1.3% of the computational effort. This is particularly impressive as it captures both the drain of energy out of the system due to the forward enstrophy cascade, and the injection of energy associated with the unresolved baroclinic instability.
Original language | English |
---|---|
Title of host publication | Proceedings of the 21st Australasian Fluid Mechanics Conference |
Editors | T C W Lau, R M Kelso |
Place of Publication | Perth WA Australia |
Publisher | Australasian Fluid Mechanics Society |
Number of pages | 4 |
ISBN (Print) | 9780646597843 |
Publication status | Published - Dec 2018 |
Externally published | Yes |
Event | Australasian Fluid Mechanics Conference 2018 - Adelaide Convention Centre, Adelaide, Australia Duration: 10 Dec 2018 → 13 Dec 2018 Conference number: 21st https://aomevents.eventsair.com/QuickEventWebsitePortal/21st-australasian-fluid-mechanics-conference/afmc2018 |
Conference
Conference | Australasian Fluid Mechanics Conference 2018 |
---|---|
Abbreviated title | AFMC 2018 |
Country | Australia |
City | Adelaide |
Period | 10/12/18 → 13/12/18 |
Internet address |