Observations of turbulent flow fields in the Chesapeake Bay estuary for tidal energy conversion

This paper presents preliminary results from a two-week long set of field experiments performed to characterize flow structure and turbulence in the mid-water column during tidal flows in the Chesapeake Bay estuary. At the deployment location, in the vicinity of Kent Island peak flood/ebb tidal flows range from +/-40 cm/s in the along-channel direction and secondary flow in the cross-channel direction reaches peak of +/-10 cm/s during the slack parts of a tidal cycle. Conditionally sampled mean velocity profiles indicate asymmetry in the flood/ebb tidal flows, which is attributed to the tidal straining. Temporal velocity spectra are presented and show modifications of the turbulence spectra due to presence of surface gravity wave field. Time history of turbulent kinetic energy dissipation rate shows variations on a tidal time scale with magnitudes ranging from 10^-6 to 10^-3 m²/s³. Results are discussed in the context of tidal turbine design and performance.