Current understanding of the ice accretion process is based largely on icin
g wind-tunnel tests. Wind-tunnel turbulence has been identified as having p
otentially important effects on the results of tests performed in icing tun
nels. The turbulence intensity level in icing tunnels in the absence of the
spray cloud had been previously measured and found to be quite high becaus
e of the lack of turbulence-reducing screens and because of the presence of
the spray system in the settling chamber. However, the turbulence intensit
y level in the presence of the spray cloud had not been measured. A method
for making such measurements was developed and a limited set of turbulence
measurements was taken in the NASA Lewis Research Center's Icing Research T
unnel (IRT). Turbulent velocity fluctuations were measured using hot-wire s
ensors. Droplets striking the wire resulted in distinct spikes in the hot-w
ire voltage that were removed using a digital acceleration threshold filter
. The remaining data were used to calculate the turbulence intensity. Using
this method, the turbulence intensity level in the IRT was found to be hig
hly dependent on nozzle air pressure, whereas other factors such as nozzle
water pressure, droplet size, and cloud liquid water content had little eff
ect.