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04:35
Preparation of Free-Surface Hyperbolic Water Vortices
Published on: July 28, 2023
Vorticity dynamics and sound generation in two-dimensional fluid flow.
Raymond J Nagem1, Guido Sandri, David Uminsky
1Department of Aerospace and Mechanical Engineering, Boston University, Boston, Massachusetts 02215, USA. nagem@bu.edu
The Journal of the Acoustical Society of America
|July 7, 2007
Summary
This study introduces a new method using vorticity expansion to analyze fluid motion and predict sound generation. The approach accurately models vortex pairs and their acoustic pressure, outperforming prior theoretical predictions.
Area of Science:
- Fluid Dynamics
- Acoustics
- Computational Physics
Background:
- Incompressible fluid equations govern fluid motion.
- Vorticity describes fluid rotation and is key to understanding complex flows.
- Predicting sound generated by fluid dynamics is crucial in many engineering applications.
Purpose of the Study:
- To develop an approximate analytical solution for two-dimensional incompressible fluid equations.
- To analyze the motion and acoustic properties of corotating Gaussian vortex pairs.
- To establish a novel method for predicting sound from distributed vorticity fields.
Main Methods:
- Expanding the vorticity field using derivatives of a Gaussian vortex.
- Deriving spatial rotation frequency directly from the fluid vorticity equation.
- Applying the expansion to the low Mach number Lighthill equation for acoustic pressure prediction.
Main Results:
- The derived rotation frequency accounts for finite vortex core size and viscosity.
- The method accurately predicts far-field acoustic pressure for Gaussian vortex pairs.
- The analytical results show superior accuracy compared to previous numerical simulations and theoretical predictions.
Conclusions:
- Vorticity expansion is an effective tool for analyzing fluid dynamics and acoustics.
- This method offers a more accurate approach to predicting sound generated by distributed vorticity.
- The findings advance the understanding of vortex dynamics and aeroacoustics.
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