A Versatile Laboratory Approach to Reproduce and Analyze Internal Ocean Wave Dynamics

TL;DR

This paper presents an accessible laboratory setup for studying internal ocean wave dynamics, demonstrating how varying the buoyancy Reynolds number influences wave breaking and turbulence, with implications for ocean science education and modeling.

Contribution

It introduces a versatile experimental method for visualizing and analyzing internal wave regimes using simple stratification and energy analysis techniques.

Findings

Three distinct wave regimes observed: no turbulence, slight turbulence, extreme turbulence.

Method enables visualization of wave breaking and turbulence transition.

Accessible approach suitable for undergraduate education and future research.

Abstract

Internal waves, or waves that propagate within a stratified fluid, may break and cause mixing. While each individual mixing event may be small, collectively, internal wave breaking drive processes in the ocean that are critical to understanding the maritime climate and biosphere. In this paper we show how to set up an experiment, suitable for an undergraduate-level lab, that illustrates a common generation and breaking mechanism in the ocean. In particular, we show how the process changes in response to a non dimensional parameter, the buoyancy Reynolds number, that can be easily varied. This parameter highlights the role of viscous vs. inertial/buoyancy forces. We outline our methods of creating a linear stratification, injecting energy with a forced topography, and analyzing the resulting dynamics with Background Oriented Schlieren and energy spectra from a conductivity probe. By altering our forcing to accommodate three values of the buoyancy Reynolds, three distinct internal wave regimes can be observed: no turbulence, slight turbulence, and extreme turbulence. Our methods aim to increase the accessibility to studying these internal waves in future experimental work, ocean modeling, and math and physics undergraduate learning.