Reynolds' Other Measurements
| Reynolds' stress is a basic property of turbulence that can be measured throughout the depth of the water column with an ADCP. When an ADCP measures velocity data there are a variety of sampling modes that can be used and similarly there are four different coordinate systems that can be used (beam, instrument, ship, and earth). If data is recorded in beam coordinates (each of the four transducers just store their velocity data in a seperate variable), a mean velocity and variance for each beam can be computed, with which two components of the Reynolds' stress tensor can be computed (namely u'w' and v'w'). There are issues with using this type of measurement scheme in low energy environments with little turbulence. However, in energetic systems this technique can provide a quantitative measure of turbulence over time throughout the water column in the system. |
Harvey Seim <harvey_seim@unc.edu>