System and Method for Determining Design Parameters for Marine Infrastructure

In the 60s-70s, a remarkable advancement was reached: instruments for directional wave measurements were developed. Data processing techniques based on potential wave theory enabled for the first time the evaluation of wave directional spectra. However, the irrotational potential theory lacks essential terms of waves and ambient shearing current interactions. By constructing suitable simulations, we proved that this disregard may lead to significant deviations in the evaluated wave directional spectra, and developed a novel suitable data processing method.

In fact, common data processing in accordance to potential theory is assuming that the ambient current is uniform or non-existent, and may result in great deviations of the evaluated wave directional spectrum from the true one. It means that the estimation of wave design parameters based on contemporary measurements using wave buoys, Acoustic Doppler Currents Profilers (ADCPs), pressure gauges, etc., in presence of the realistic ambient shearing currents, might suffer from significant inaccuracies.

Development of new numerical transfer functions based on rotational wave theory and employing these new transfer functions in cross-spectra products’ measurements. Then, the directional spectrum reconstruction can be obtained by solving its Fourier coefficients accounting for the shearing currents. 
The great advantage in accounting for the ambient current is the possibility to accurately determine the directional wave spread function and to distribute the energy between the wave frequencies due to the derivation of the actual intrinsic frequency. We are confident that the new processing method will become the leading method and there will be no escape, in the future, from adapting all the devices to include current measurement of the water column.

Hardware, and software routine installed on measurement systems.

1. Companies that manufacture point measurement devices and in particular ADCPs that measure both the waves and the current velocity profile in depth. The processing method can also be adjusted and applied to measurements of other sensors such as wave buoys, pressure gauges using a measured or estimated current profile, both in-situ and for laboratories.
2. Planning and consulting companies, governmental environment and coastal protection agencies, and laboratories in the marine engineering field that provide engineering assessments of marine infrastructure location, sediment transport (sand) along the coast, maritime structures’ design, climate change and more, based on wave measurements and numerical models. They will need to correct the processing of any future project as well as their entire historical wave measurement data and design models.

Novel simulation assuming wave propagation in presence of shearing currents proved that significant deviations of wave directions occur in the common potential data processing method for realistic sea conditions. 
The simulation proved that the new developed data processing methodology corrects these inherent flaws (Figure 1). 
Note that even a few degrees of an error in mean wave direction can lead to a completely wrong estimation of sediment transport direction and hence a construction of an inappropriate coastal protection structure.
Currently, the new methodology is implemented for in-situ ADCP measurements collected off-shore the Israeli Mediterranean coast.

Soffer, Kit, and Toledo (2022), “System and Method for Determining Design Parameters for Marine Infrastructure”, (US Patent and Trademark Office, Patent provisional application No. 63/375,388), 

Soffer et al. (submitted), “New Method of Directional Spectrum Estimation Accounting for the Ambient Shearing Currents”.

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