The second and third invariants of the Reynolds stress anisotropy tens
or and the Reynolds stress dissipation rate anisotropy tensor have bee
n evaluated from direct numerical simulation data for a boundary layer
. The departure from isotropy increases in both inner and outer region
s of the layer as the momentum thickness Reynolds number R(theta) decr
eases. The relationship between the two anisotropy tensors has been ex
amined in some detail. A linear relation, with a constant of proportio
nality depending on the local turbulence Reynolds number, is well supp
orted by the outer region data for three values of R(theta).