# Characteristic Numbers of Tidal Energy Transport

### From BAWiki

## Motivation

Computation as well as visualization of the tide independent characteristic numbers of tidal barotropic energy transport gives some insight into the (mean)

- local dissipation of tidal energy,
- transmitted energy (work due to perturbation pressure) by the tidal wave, as well as the
- flux of kinetic energy

within the period of data analysis.

From these, conclusions can be drawn with respect to the (residual) transport as well as dissipation of (barotropic) tidal energy. The mean energy flux is typically dominated by the perturbation pressure work of the tidal wave.

During computation within UNTRIM2007 and UNTRIM2 only the two most significant terms (processes) are taken into account so far (see above). For this reason dissipation can only be approximately determined. Its magnitude should be correct anyway for estuaries with significant tidal range.

Literature:

- Dujuan Kang and Oliver Fringer, 2012:
*Energetics of Barotropic and Baroclinic Tides in the Monterey Bay Area*. Journal of Physical Oceanography, 42, 272–290. doi: http://dx.doi.org/10.1175/JPO-D-11-039.1.

## Definitions for the tide-independent characteristic numbers of tidal energy transport

**An automatic analysis is carried through by the computer program NCANALYSE.**

### Divergence of horizontal barotropic tidal energy transport

(Mean) divergence (MW) of horizontal barotropic energy flux within the period of analysis for all computational cells (control volumes). Divergence is actually computed taking

- energy flux due to horizontal barotropic pressure work by the tidal wave, and
- flux of barotropic kinetic energy

into acount.

*No example graphics available yet*.

Data analysis: NCANALYSE.

### Horizontal energy flux due to perturbation pressure work

(Mean) horizontal energy flux (MW) for the period of analysis at edges (lateral faces of control volumes).

*No example graphics available yet*.

Data analysis: NCANALYSE.

### Horizontal energy flux due to transport of kinetic energy

(Mean) horizontal energy flux (MW) for the period of analysis at edges (lateral faces of control volumes).

*No example graphics available yet*.

Data analysis: NCANALYSE.

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