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Synthesis

Fluid flow numerical models have been used in at least two previous occasions with the aim of predicting seeing. It appears that, while the method is applicable in principle, there are also practical difficulties linked to the size of the model, the definition of the initial and boundary conditions, and the possibility to validate the computation by means of representative tests.

We have attempted here an application to the problem of mirror seeing in which we have parameterized the local profile by means of a similarity relationship. The case of a mirror within a closed tube and ventilated by fans was simulated with interesting results.

The conclusions that can be drawn from this study are that a simulation with a similarity parameterization of the profile is feasible and appears to give realistic results.

The limitations of this approach are however intrinsic to the utilization of a CFD model. Indeed the main advantage of CFD models is in the possibility to simulate particular cases and conditions which cannot be represented by simple relationships or for which there are no experimental data. On the other hand the parameterization refers to a well characterized steady state condition and may not be as accurate in the actual model conditions.



next up previous contents
Next: Surface layer seeing Up: Numerical models Previous: Application to a



Lorenzo Zago, lorenzo.zago@heig-vd.ch, Mon Nov 6 23:33:14 GMT+0100 1995