Empirical estimation: turbulent flow
The characterization of the turbulent flows can be achieved using multifractal formalism, it had been showed in literature that the UM model reproduces well the statistics of the measured field in geophysics. The UM parameters have been estimated for different measured fields in geophysics, such as : velocity, temperature. We will give in this slide the estimation of
for the wind velocity field and temperature field. The dimensional analysis performed on the Navier-Stokes equations and the advection-diffusion equation provides the expressions of fluxes which are defined as below:

Where
represents the flux for the velocity field,
the flux for the temperature field and
the temperature variance. The data sets were measured in wind-tunnel, for the velocity: field the sampling frequency is
and the time duration is about
, for the temperature field: the sampling frequency is
and the time duration is
.

The estimation of the UM parameters passes through the statistical moment function
:

The obtained UM parameters are: for the wind velocity
and for temperature field
.