Eddy viscosity for turbulent flows
FP4 — Training and Mobility of Researchers
- Duration
- 1996-10-01 → 1999-09-30
- EU contribution
- —
- Participants
- 2
- Scheme
- RGI
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Project objective
Direct numerical simulation of two and three dimensional fully developed turbulent flows is one of the basic research activities in computational physics. In most cases, for practical applications, one would like to introduce an effective viscosity aimed at simulating the small scale dynamics on large scale flows. The main challenge stems on the idea of reducing the computational problem in a way suitable for present supercomputers. Actual modelizations of small scale statistics are mainly based on pure phenomenological ideas. Eddy viscosities used in Large-Eddy-Simulations for three dimensional flows derive from simple closure ansatz on the statistics of energy transfer. The existence of an intermittent energy transfer leads to the necessity of revising classical modelizations based on the Kolmogorov 1941 Theory. The aim of this project is to combine ideas coming from multiple scale definition of eddy viscosity and recent results by using Extended-Self-Similarity for determining scaling laws in turbulence, in order to analyze in deep details for the first time, the effect of suitable eddy viscosities in numerical simulations. The equip of Prof. Uriel Frisch at the OCA is one of the most active European group in these fields. In particular, we intend to use two and three dimensional numerical codes to test quantitatively the degree of intermittency introduced by using more rigorous mathematical definition of eddy viscosity (by multiple scale analysis) and a rather accurate estimate of anomalous scaling using the concept of Extended-Self-Similarity. This research area is under active investigation in the scientific community for the potential revenue of engineering applications and in particular for the automotive and aeronautics industrial applications. Among the possible outcomes of this project we expect to define: the effects of eddy viscosity on the anomalous scaling laws in homogeneous isotropic turbulence: the enhancement, or reduction, of intermittent fluctuations due to small scale parametrization in homogeneous shear flows; the eddy diffusivity for turbulent transport of passive scalars in homogeneous isotropic turbulence and the effect of eddy viscosity in boundaly layer turbulence.
Original text from CORDIS.
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