Smirnov et al.[16] further modified Kraichnan's [15] method to allow anisotropic turbulent velocity fluctuations to be specified. In this case, the local Reynolds stress tensor,
is specified together with the local length scale,
.
Before applying the spectrum of random numbers, the local Reynolds stress tensor is rotated into its principal coordinates, to obtain a diagonal tensor
. The wave number sequence,
, is modified as follows:
| (145) |
where
,
and
are the components of the
vector and
,
and
are the diagonal components of
.
The spectrum is then applied as follows to obtain an intermediate field of velocity fluctuations:
| (146) |
where
,
,
,
,
,
and
are defined as with the isotropic field.
This intermediate field, termed
is then scaled as follows:
| (147) |
where
,
and
are the components of
.
Finally, the field of velocity fluctuations,
, is obtained by rotating
from the principal coordinates of
back into flow field's coordinates.