TR No, 22 
ABSTRACT 
Measurements were made of the component of turbulent velocity along 
the axis of a 3-knot tidal current 1.5 meters below the water surface 
using a ducted impeller current meter. Values of the one-dimensional 
energy spectra were computed on a digital computer at wave numbers from 
0 em-l to 0.157 cm=), The composite energy spectrum obtained from the 
individual spectra was of the -5/3 power law form predicted by the 
Kolmogoroff hypothesis for wave numbers from 0.01 cm=! to 0,026 cm-l. 
At higher wave numbers the energy spectrum decreased more rapidly than 
predicted because of attenuation of the turbulent velocity variations 
caused by the relatively large size of the current meter. The average 
variance for the field of turbulence was 55.6 cm2 - sec~* 425.0 (standard 
error), and the average rate of energy dissipation by viscosity was es- 
timated using the Kolmogoroff hypothesis as 0.84 em? - sec”, 
ii 
