# A Method for Real-Time Measurement of the Vertical Vortex at Flood Discharge Outlets Using Ultrasonic Sensors

## TL;DR

This paper introduces a real-time method using ultrasonic sensors to measure vertical vortices at flood discharge outlets, validated through simulations and experiments.

## Contribution

A novel ultrasonic-based method for real-time vertical vortex measurement is proposed and validated.

## Key findings

- The acoustic measurement method effectively determines vertical vortex parameters with a core radius of 0.03–0.05 m.
- The maximum tangential velocity measurement error is within 10% using ultrasonic sensors.
- The method was validated through CFD simulations and laboratory experiments.

## Abstract

In this study, ultrasonic sensors were used to measure the vertical vortex at flood discharge outlets in real time, and numerical simulations and model experiments were conducted. When a sound signal passes through a vortex, its propagation characteristics will change, which helps to determine the existence of the vortex. Moreover, its characteristic parameters can be obtained through inversion. In this paper, first, the theories of acoustic measurement methods were introduced and their feasibility was verified through a comparison between Particle Image Velocimetry (PIV) measurement and numerical simulation results. Then, the Computational Fluid Dynamics (CFD) method was used to simulate the vertical vortex at the flood discharge outlets of hydraulic structures and the simulation data were restored to the actual size at scale. Finally, acoustic numerical simulations of actual vortex data were conducted, and ultrasonic sensors were used to measure the velocity of a simplified vertical vortex model under laboratory conditions. The research results indicate that the acoustic measurement method proposed in this article is effective in the measurement of the characteristic parameters of vertical vortex with a core radius of 0.03~0.05 m and a maximum tangential velocity of 0.5 m/s, the measurement error of the maximum tangential velocity is within 10%.