A new method for determining the slow and rapid pressure-strain
rate terms directly
from wind-tunnel experiments has been developed with the aid of a newly
developed
theoretical description of the kinematics of homogeneous axisymmetric turbulence.
Both the straining and the return-to-isotropy process of homogeneous axisymmetric
turbulence are studied with the aim of improving Reynolds stress closures.
Direct
experimental determination of the different terms in the transport equation
for the
Reynolds stress tensor plays a major role in the validation and development
of turbulence
models. For the first time it is shown that the pressure{strain correlation
can
be determined with good accuracy without balancing it out from the Reynolds
stress
transport equation (and without measuring the pressure). Instead it is
determined
through evaluation of integrals containing second- and third-order two-point
velocity
correlations. All the terms in the Reynolds stress equations are measured
directly and
balance is achieved.