The paper describes a combined experimental and computational study of
laminar and turbulent flow between contrarotating disks. Laminar comp
utations produce Batchelor-type flaw: Radial outflow occurs in boundar
y layers on the disks and inflow is confined to a thin shear layer in
the midplane; between the boundary layers and the shear layer, two con
trarotating cores of fluid are formed Turbulent computations (using a
low-Reynolds-number k-epsilon turbulence model) and LDA measurements p
rovide no evidence for Batchelor-type flow, even for rotational Reynol
ds numbers as low as 2.2 x 10(4). While separate boundary layers are f
ormed on the disks, radial inflow occurs in a single interior core tha
t extends between the two boundary layers; in the core, rotational eff
ects are weak. Although the flow in the core was always found to be tu
rbulent, the flow in the boundary layers could remain laminar for rota
tional Reynolds numbers up to 1.2 x 10(5). For the case of a superpose
d outflow there is a source region in which the radial component of ve
locity is everywhere positive; radially outward of this region the flo
w is similar to that described above. Although the turbulence model ex
hibited premature transition from laminar to turbulent flow in the bou
ndary layers, agreement between the computed and measured radial and t
angential components of velocity was mainly good over a wide range of
nondimensional flow rates and rotational Reynolds numbers.