Towards Full Field Scaling of the Centerline Behavior for Initially Turbulent Axisymmetric Jets.
Towards Full Field Scaling of the Centerline Behavior
for Initially Turbulent Axisymmetric Jets.
(654 K)
Papadopoulos, G.; Pitts, W. M.
FEDSM98-4892;
Summer Meeting. American Society of Mechanical
Engineers (ASME)/Fluids Engineering Division. FEDSM'98.
Proceedings. June 21-25, 1998, Washington, DC, 1-7 pp,
1998.
Keywords:
turbulent jets; flow measurement; turbulence; turbulent
flow; velocity measurement
Abstract:
Recently the authors introduced a length scale for
effectively collapsing the near field centerline
velocity and mass fraction of constant and variable
density axisymmetric jets whose initial conditions
correspond to those of fully developed turbulent pipe
flow. The new length scale incorporated the initial
mass, momentum and turbulence intensity fluxes to
capture the Reynolds number dependence of near field
development for the velocity and scalar distributions
often observed in low Reynolds number turbulent jets.
The present paper makes the normalization technique more
robust by extending its applicability to the
intermediate and far fields using a dynamic length scale
based on the local centerline turbulence intensity. The
normalized velocity distributions of a constant density
jet at several Reynolds numbers collapse over the entire
length of jet development when the axial distance is
normalized by the proposed length scale, thus achieving
Reynolds number independence.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899