Research Question
Taylor-Couette flow arises from the relative rotation of coaxial cylinders and is a classic model for studying rotating shear flow, flow instability, and the evolution of vortex structures. In the Taylor-Couette configuration with a rotating inner cylinder and a stationary outer cylinder, this study uses LDV measurements to compare the radial and axial velocity distributions, local rheological behavior, and Taylor vortex structure of Newtonian and shear-thinning fluids. The flow apparatus, optical measurement, rheological characterization, and data processing are connected into a complete research pipeline, yielding reliable flow-field evidence.
Experimental Platform
To make repeatable radial and axial measurements across different fluids and operating conditions, the experimental platform integrates a transparent coaxial-cylinder flow apparatus, a drive with torque/speed monitoring, LDV, 3-axis positioning, optical compensation, and data acquisition into a single system. The flow apparatus defines the flow-field experimental boundary; the 3-axis stage moves the LDV probe according to the measurement plan; optical compensation improves the interpretability of measurement positions; and rheological testing and data processing turn discrete velocity data into comparable flow-field evidence.
LDV & Optical Compensation
LDV forms a local measurement volume where two laser beams intersect, enabling non-intrusive velocity measurement. The curved cylinder of the Taylor-Couette apparatus alters the refraction path of the laser beams, causing measurement-position offset and measurement-volume separation. To address this, a transparent viewing chamber was designed and applied, using flat outer surfaces and KSCN refractive-index matching to reduce the effect of curved-surface refraction.
Relative to the uncompensated case, the viewing chamber and refractive-index matching markedly reduce the measurement-position offset caused by curved-surface refraction.
Fabricated viewing chamber (SLA 3D print)
Experiment & Data Pipeline
One Newtonian fluid (70.0 wt.% glycerol–water solution) and two shear-thinning fluids (0.1 wt.% and 0.4 wt.% xanthan gum solution).
Material properties obtained from rheological testing and Power-law / Carreau model fitting.
Radial and axial measurements performed with LDV; Matlab used for repeated-measurement statistics, position correction, and profile fitting, yielding shear rate, local viscosity, local Reynolds number, and related quantities.
Flow-Field Results
- Local rheology distribution: radial measurements show that shear-thinning fluids form a "low viscosity near the wall — high viscosity in the middle — low viscosity near the wall" sandwich structure, which becomes clearer as the Reynolds number increases.
- Taylor vortex structure: axial measurements reveal the time-averaged Taylor vortex structure. The Newtonian fluid shows a consistent spatial period, while the non-Newtonian fluids exhibit different vortex modes and wavelengths.
Taylor-Couette flow visualization
What Carries Over
Top-level system design works backward from the research goal to the whole system
Decompose the research goal into a coordinated apparatus, measurement, and data pipeline.
Prioritize what matters; let secondary problems yield to the main one
Identify the dominant error sources, then form and validate an actionable solution.
A design must come down to an apparatus that actually runs
Integrate design, equipment, and method into a working experimental system.
Learn whatever the work requires
Rapidly master cross-disciplinary methods and apply them to real problems.