|
|
|
|
|
| Resseguier, Valentin; Memin, Etienne; Heitz, Dominique; Chapron, Bertrand. |
| We present here a new stochastic modelling approach in the constitution of fluid flow reduced-order models. This framework introduces a spatially inhomogeneous random field to represent the unresolved small-scale velocity component. Such a decomposition of the velocity in terms of a smooth large-scale velocity component and a rough, highly oscillating component gives rise, without any supplementary assumption, to a large-scale flow dynamics that includes a modified advection term together with an inhomogeneous diffusion term. Both of those terms, related respectively to turbophoresis and mixing effects, depend on the variance of the unresolved small-scale velocity component. They bring an explicit subgrid term to the reduced system which enables us to take... |
| Tipo: Text |
Palavras-chave: Low-dimensional models; Turbulence modelling; Turbulent mixing. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00396/50698/53726.pdf |
| |
|
|
| Resseguier, Valentin; Memin, Etienne; Chapron, Bertrand. |
| In large-scale Fluids Dynamics systems, the velocity lives in a broad range of scales. To be able to simulate its large-scale component, the flow can be de- composed into a finite variation process, which represents a smooth large-scale velocity component, and a martingale part, associated to the highly oscillating small-scale velocities. Within this general framework, a stochastic representation of the Navier-Stokes equations can be derived, based on physical conservation laws. In this equation, a diffusive sub-grid tensor appears naturally and gener- alizes classical sub-grid tensors. Here, a dimensionally reduced large-scale simulation is performed. A Galerkin projection of our Navier-Stokes equation is done on a Proper Orthogonal De- composition basis.... |
| Tipo: Text |
Palavras-chave: Stochastic calculus; Uid dynamics; Large eddy simulation; Proper Orthogonal Decomposition; Reduced order model; Uncertainty quantification. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00320/43080/42607.pdf |
| |
|
|
|
