On the Estimation of the Surface Elevation of Regular and Irregular Waves Using the Velocity Field of Bubbles

Abstract

This paper describes a new set of experiments focused on estimating time series of the free surface elevation of water (FSEW) from velocities recorded by submerged air bubbles under regular and irregular waves using a low-cost non-intrusive technique. The main purpose is to compute wave heights and periods using time series of velocities recorded at any depth. The velocities were taken from the tracking of a bubble curtain with only one high-speed digital video camera and a bubble generator. These experiments eliminate the need of intrusive instruments while the methodology can also be applied if the free surface is not visible or even if only part of the depth can be recorded. The estimation of the FSEW was successful for regular waves and reasonably accurate for irregular waves. Moreover, the algorithm to reconstruct the FSEW showed better results for larger wave amplitudes.

Bringing optical fluid motion analysis to the field: a methodology using an open source ROV as a camera system and rising bubbles as tracers

“…It is very challenging to maintain an acceptable concentration of particles and at the same time avoid intrusive mixing motion. The adaptation of PIV using bubbles as tracers has become popular throughout different applications [9][10][11][12][13], and tested against more common seeding methods [14]. The mentioned studies have brought to light different aspects that need to be calibrated and considered to apply these techniques outside a controlled environment.…”

Bringing optical fluid motion analysis to the field: a methodology using an open source ROV as camera system and rising bubbles as tracers

“…Therefore, the introduction of environmentalfriendly tracers is required. The adaptation of PIV using bubbles as tracers has become popular throughout different applications (Delnoij et al 1999, de la Torre et al 2015, Ryu et al 2005, Rivillas-Ospina et al 2012, Cheng et al 2005, and tested against more commonly seeding methods (Vargas et al 2020). The mentioned studies have brought to light different aspects that need to be calibrated and considered to apply these techniques outside a controlled environment.…”

Signals and Images in Sea Technologies

“…In this context, imaging can be used to determine the velocity field of bubbles, providing a non-intrusive technique for the kinematic study of the Free Surface Elevation of Water (FSEW). In the paper by Vargas et al [5] entitled "On the Estimation of the Surface Elevation of Regular and Irregular Waves Using the Velocity Field of Bubbles", imaging is used to infer the wave velocities and forces acting on maritime infrastructure, one of the most challenging topics in the field of Coastal Engineering and Fluid Dynamics. In the study, a curtain of artificial bubbles was generated by a compressed air device placed at the bottom of the flume.…”