EDDY DIFFUSIVITY IN A TURBULENT PIPE FLOW WITH UNIFORM FLUID INJECTION AND SUCTION THROUGH THE WALL

Abstract

A theoretical and experimental study was conducted on a fully developed turbulent pipe flow with uniform fluid injection or suction through the wall.
A simple model was used to analyze the effect of injection or suction on the eddy diffusivity of momentum, friction factor and pressure gradient. The model predicts that both the normalized eddy diffusivity and local friction factor are linear functions of m/(-dp^*/dx^*), that is),
ε_M/vRe(-dp^*/dx^*)=F₁(y/R)•m/(-dp^*/dx^*)+F₂(y/R)
f^•(-dp^*/dx^*)=1/2+4m/(-dp^*/dx^*)
and that dp^*/dx^*=fn (m). Functions F₁(y/R), F₂(y/R) and fn(m) were determined by experiment.
The experimental runs were executed at Re=15, 200-95, 300 with wall flux ratio m=vW/<u>=-0.0042-0.00847.