Remote-sensing of hydrodynamics in Tokyo Bay and Bakan Strait

Abstract

In the inertia range, turbulent energy is concentrated in eddies. The eddies interact, dissipate the kinetic energy and reduces the eddy size. The turbulent velocity fields are measured by inverting the acoustic wave attenuation by volume scattering. The eddy viscosity ε is the rate of kinetic energy dissipation of the turbulence. Acoustic wave dissipation is roughly proportional to (velocity intensity fluctuations) ε, 2/3. The Reynolds stresses are also induced by the velocity intensity fluctuations ε, 2/3. The Reynolds stresses take various forms, such as Rip currents, wave set-ups, etc. The acoustic wave volume scattering, transmission loss by volume scattering, turbulent fields, Reynolds stresses, and eddy viscosity fields are inverted from eight point transmission lines in two completely different turbulent flow fields. They are Tokyo Bay (ε ∼ 0.02) and Bakan Strait (ε ∼ 1.2). The Reynolds stresses are in Tokyo Bay (∼33 kPa) and in Bakan Strait (∼1200 kPa). The side by side comparisons of the two data sets reviles the quite complicated differences in their responses to turbulent current field which will be presented in this paper.