Abstract
The present study characterizes published acoustic Doppler current profiler measurements from twenty potential tidal energy sites, classifying the profiles based on their velocity shape, while analyzing their prevalence and mean characteristics by flow regime. Most of the observed profiles (87%) are monotonic. A 1/6.5th power law models 89% of the mean profiles within ±10%. A small fraction of the profiles (13%) exhibits non-monotonic behavior during different phases of the tidal cycle or in the presence of complex bathymetric features and other hydrodynamic forcing. Non-monotonic behavior is found to be correlated with the flow depth Reynolds number, indicating the influence of depth and local turbulence intensity in shaping the vertical flow structure. While its occurrence is low compared to monotonic behavior, it is characterized by sharp velocity gradients and velocity deficits that impact turbine design and energy production by increasing shear forces and altering load distributions. These findings demonstrate the efficacy of canonical power law models commonly used to approximate reference inflow conditions for current energy converters but underscore the need for detailed profile characterization for tidal energy resource assessment, tidal energy converter design, and power performance assessment.