Near-wall transfer rate: logarithmic-law "wall-function"
Illustrations.
7. Conclusions
The results which have been presented appear to justify the
following conclusions:
- With a single value for the micro-mixing constant CONMIX, namely
5.0, it appears to be possible to fit, with fair accuracy,
experimental data for distributions of:
- mean velocity,
- velocity fluctuations,
- mean temperature,
- temperature fluctuations.
for all the near-wall flows which have been investigated so far.
- The pressure-gradient source in the velocity-PDF equations has
successfully enabled fully-developed flow conditions to be predicted.
- The computational expense of procuring population-grid-independent
solutions has proved to be easily affordable.
- The treatment of the whole near-wall layer as a generalised "Reynolds
Flux" enables the effects of a wall on the fluctuations in the interior
of a flow to be accurately simulated.
- It has been shown that MFM can be used simultaneously with Kolmogorov-style
turbulence models such as k-epsilon and LVEL. It does not however need
to rely on these.
Further applications and developments which immediately suggest
themselves include:
- re-working the developing-pipe-flow problem with the effective
viscosity proportional to the RMS velocity fluctuations and the
distance from the wall, and thus dispensing with both k-epsilon and
LVEL;
- applying the model to wall-jet flows, for which plentiful data are
available;
- allowing for reletive motion between the various fluids of the
population under the influence of pressure gradient and density
variations.
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the possibilities of future development
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