# Experiments on barotropic-baroclinic conversion and the applicability of linear n-layer internal wave theories

## TL;DR

This study experimentally investigates internal waves in a stratified fluid, examining energy conversion and comparing observed wave speeds with linear multi-layer theories, finding good agreement despite large wave amplitudes.

## Contribution

It provides experimental validation of linear 2- and 3-layer internal wave theories in a stratified fluid with energy conversion from barotropic to baroclinic modes.

## Key findings

- Linear 3-layer theory agrees well with experimental wave speeds.
- Internal waves can have large amplitudes yet still be modeled linearly.
- Barotropic energy conversion is facilitated by bottom obstacles.

## Abstract

Interfacial internal waves in a stratified fluid excited by periodic free-surface perturbations in a closed tank are studied experimentally. Barotropic-baroclinic energy conversion is induced by the presence of a bottom obstacle. The connection between horizontal surface velocities and internal wave amplitudes is investigated, the developing flow patterns are described qualitatively, and the wave speeds of internal waves are systematically analyzed and compared to linear 2- and 3-layer theories. We find that, despite of the fact that the observed internal waves can have considerable amplitudes, a linear 3-layer approximation still gives fairly good agreement with the experimental results.