Virtual seafloor concept enables accurate estimates of tidal energy conversion
Publication: Virtual seafloor reduces internal wave generation by tidal flow, Likun Zhang and Harry L. Swinney, Phys. Rev. Lett., 112, 104502 (2014) [Link]
APS Physics: “Synopsis: Motion in the Ocean: A new study suggests only the topmost part of the seafloor is relevant in determining the conversion of tidal energy to wave energy in the ocean”. [Link]
Tidal flow over mountains and valleys on the ocean floor produces waves that travel long distances inside the ocean. The energy in these oceanic internal waves contributes significantly to the ocean’s energy budget, which is a factor in determining the earth’s climate. However, the amount of tidal energy converted to internal wave energy is difficult to calculate because of the irregular shape of the ocean bottom. Our computer simulations and analyses reveal that the calculation could be simplified by using the concept of a “virtual seafloor” between neighboring peaks, as indicated by the horizontal dashed lines in the figure above (red indicates internal ocean waves carrying energy upward from the seafloor, and blue indicates waves carrying energy downward). Topography below the virtual floor between neighboring peaks produces no internal waves; thus it is sufficient to consider only topography that rises above the virtual floor. The virtual floor concept should enable possible more accurate estimates of the energy converted from the tides into internal waves in the oceans.