The Mathematical Institute, University of Oxford, Eprints Archive

On dynamic computational subgrid modeling

Hoffman, Johan and Johnson, Claes (1999) On dynamic computational subgrid modeling. Technical Report. Unspecified. (Submitted)



In this paper we study a subgrid model based on extrapolation of a corrective force, in the case of a linear convection-diffusion problem $Lu=f$ in one dimension. The running average $u^{h}$ of the exact solution $u$ on the finest computational scale $h$ satisfies an equation $L_{h}u^{h}=[f]^{h}+F_{h}$, where $L_{h}$ is the operator used in the computation on the scale $h$, $[f]^{h}$ is the approximation of $f$ on the scale $h$, and $F_{h}$ acts as a corrective force, which needs to be modeled. The subgrid modeling problem is to compute approximations of $F_{h}$ without using finer scales than $h$. In this study we model $F_{h}$ by extrapolation from coarser scales than $h$ where the corrective force is directly computed with the finest scale $h$ as reference. We show in experiments that a corrected solution with subgrid model on scale $h$ corresponds to a non-corrected solution on less than $h/4$.

Item Type:Technical Report (Technical Report)
Subjects:H - N > Numerical analysis
Research Groups:Numerical Analysis Group
ID Code:1285
Deposited By: Lotti Ekert
Deposited On:01 Jun 2011 08:20
Last Modified:29 May 2015 18:58

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