Applying Laser Doppler Anemometry inside a Taylor-Couette geometry - Using a ray-tracer to correct for curvature effects

TL;DR

This paper introduces a ray-tracer based method to correct curvature effects in Laser Doppler Anemometry measurements within a Taylor-Couette setup, enabling accurate velocity profiling in complex geometries.

Contribution

It presents a novel application of ray-tracing for curvature correction in LDV measurements, addressing limitations of conventional methods in curved geometries.

Findings

Ray-tracer accurately predicts focal positions and corrects velocity measurements.

Corrected measurements show good agreement with theoretical velocity profiles.

Method enables precise flow measurement in high Reynolds number Taylor-Couette flow.

Abstract

In the present work it will be shown how the curvature of the outer cylinder affects Laser Doppler anemometry measurements inside a Taylor-Couette apparatus. The measurement position and the measured velocity are altered by curved surfaces. Conventional methods for curvature correction are not applicable to our setup, and it will be shown how a ray-tracer can be used to solve this complication. By using a ray-tracer the focal position can be calculated, and the velocity can be corrected. The results of the ray-tracer are verified by measuring an a priori known velocity field, and after applying refractive corrections good agreement with theoretical predictions are found. The methods described in this paper are applied to measure the azimuthal velocity profiles in high Reynolds number Taylor-Couette flow for the case of outer cylinder rotation.