The formulas for the temporal variations of the maximum streamwise penetration distances of self-preserving unsteady round nonbuoyant turbulent starting jets and puffs in still fluids were stated incorrectly in the originally published paper. The correct versions can be found from conservation of the specific momentum flux, $Q˙ouo,$ for starting jets and from conservation of the specific momentum force, $Qouo,$ for puffs, as follows:
$xp−xo/d=Cxt−td/t*n,$
(1)
where
$t*=d2/Q˙ouo1/2,n=1/2,startingjet$
(2)
and
$t*=d4/Q˙ouo,n=1/4,puff.$
(3)
Within the self-preserving region a specific source property, such as the source diameter, is no longer relevant and can be factored out of Eqs. (123) to yield the following compact equations for the maximum streamwise penetration distances within the self-preserving region:
$xp−xo/Q˙ouo1/2t−td1/2=Cx,startingjet$
(4)
and
$xp−xo/Qouot−td1/4=Cx,puff.$
(5)
The corresponding variations of the maximum radial penetration distances of self-preserving starting jets and puffs, however, are identical:
$rp/xp−xo=Cr.$
(6)
Measurements of maximum streamwise and radial penetrationdistances of starting jets and puffs are plotted in Figs. 1 and 2 according to Eqs. (456). These results were obtained from new measurements over the test range considered in the original paper. The near-source properties of both flows vary as source properties are varied, however, self-preserving behavior satisfying Eqs. (456) is achieved for streamwise distances greater than 20–30 source diameters from the source. The various parameters of Eqs. (456), with uncertainties (95 percent confidence) shown in parentheses, are as follows:
$Cx=2.80.06,Cr=0.150.003,xo/d≈0,startingjet$
(7)
and
$Cx=2.60.06,Cr=0.170.005,xo/d=8.52.0,puff$
(8)
where $xo/d$ for starting jets could not be distinguished from the exit of the source whereas $xo/d$ for puffs was independent of the amount of source fluid injected for the present test range, e.g., $Qo/Aod=60-320.$ This includes flows that were identified as interrupted jets, with $Qo/Aod=159-191,$ in the originally published paper.
1
1
Close modal
2
2
Close modal