D. Diiorio et Dm. Farmer, PATH-AVERAGED TURBULENT DISSIPATION MEASUREMENTS USING HIGH-FREQUENCYACOUSTICAL SCINTILLATION ANALYSIS, The Journal of the Acoustical Society of America, 96(2), 1994, pp. 1056-1069
The path-averaged turbulent kinetic energy dissipation (per unit mass)
is estimated in a shallow tidal channel using acoustical scintillatio
n analysis. The tidal current ensures that fully developed turbulence
prevails. In order to make measurements of the turbulence parameters,
a high-frequency (67-kHz) acoustic propagation experiment was conducte
d. Our acoustic data is compared to the weak scattering theory of Tata
rski assuming a Kolmogorov turbulence model and compared with availabl
e oceanographic data. Analysis of log-amplitude, phase, and phase-diff
erence spectra shows close agreement with the theory. Comparison of th
e acoustic data with direct measurement of temperature and salinity fl
uctuations using in situ sensors allows evaluation of the contribution
of turbulent velocity fluctuations to the scintillation signal. The r
esults show that turbulent velocity fluctuations are the dominant (sim
ilar to 95%) component of the observed acoustic scintillation, leading
to estimates of the path-averaged turbulent energy dissipation, which
rises and falls with the tidal current (epsilon similar to 10(-7)-10(
-5) m(2)s(-3)). A confirmation of the validity of the weak scattering
theory together with the Kolmogorov turbulence model in this environme
nt is given within the context of the scattering strength-refractive i
ndex variance parameters (Gamma,X).