Thesis etd-03272015-131318 |
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Thesis type
Tesi di laurea magistrale
Author
NOVI, LYUBA
URN
etd-03272015-131318
Thesis title
Sensitivity of the mesoscale quasi-geostrophic turbulence to the numerical advection scheme: application to an Antarctic Ocean channel dynamics
Department
INGEGNERIA CIVILE E INDUSTRIALE
Course of study
INGEGNERIA AEROSPAZIALE
Supervisors
relatore Prof. Salvetti, Maria Vittoria
Keywords
- applied mathematics.
- cfd
- fluid dynamics
- turbulence
Graduation session start date
28/04/2015
Availability
Full
Summary
The interactions of mesoscale eddies cause the potential enstrophy (the variance
of potential vorticity) to be transferred toward small scales. To prevent
a pileup of potential enstrophy at the grid size scale, models should dissipate
the enstrophy. This can be done explicitly or implicitly via the the advection
scheme. We explore the second choice and compare a set of schemes
(2nd order MUSCL type, the ROMS one and two 5th order ones including a
WENO). The comparison is done with a 3D QG model in a forced-dissipated
turbulent regime. We assess the behavior with resolution. We nd a significant
impact of the advection scheme on the turbulence, likely due to the
inverse cascade of kinetic energy. We are able to diagnose the spectral signature
of the implicit dissipation for each scheme. This reveals and explains
why the eddy kinetic energy can so dramatically dier from one scheme to
the other. Statistically convergence is also assessed, as well as robustness
with c
. In conclusion this work is aimed at exploring the eects of implicit
dissipation in the eddy resolving regime.
of potential vorticity) to be transferred toward small scales. To prevent
a pileup of potential enstrophy at the grid size scale, models should dissipate
the enstrophy. This can be done explicitly or implicitly via the the advection
scheme. We explore the second choice and compare a set of schemes
(2nd order MUSCL type, the ROMS one and two 5th order ones including a
WENO). The comparison is done with a 3D QG model in a forced-dissipated
turbulent regime. We assess the behavior with resolution. We nd a significant
impact of the advection scheme on the turbulence, likely due to the
inverse cascade of kinetic energy. We are able to diagnose the spectral signature
of the implicit dissipation for each scheme. This reveals and explains
why the eddy kinetic energy can so dramatically dier from one scheme to
the other. Statistically convergence is also assessed, as well as robustness
with c
. In conclusion this work is aimed at exploring the eects of implicit
dissipation in the eddy resolving regime.
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