Advanced optical measurement techniques for simultaneous fibre orientation and flow analysis complemented by machine...

Area of Science:

• Fluid Dynamics
• Materials Science
• Optical Measurement Techniques

Background:

• Understanding fiber orientation in fluid suspensions is crucial for material properties.
• Existing methods often lack the resolution or simultaneity to capture dynamic orientation processes.
• Transparent fluids like concrete substitutes and polymer melts present unique challenges for visualization.

Purpose of the Study:

• To develop and present a novel time-resolved, quasi-simultaneous measurement method for fiber orientation and flow velocity.
• To visualize and better understand the flow-related fiber orientation process.
• To analyze the interplay between velocity fields and fiber motion.

Main Methods:

• A PIV-based (Particle Image Velocimetry) measurement stand was engineered for simultaneous flow and fiber analysis.
• Phosphorescence imaging under black light was employed to visualize individual fibers within the transparent fluid.
• A random forest algorithm was utilized for accurate fiber detection with minimal training data and processing time.

Main Results:

• The study successfully visualized the dynamic process of fiber orientation in relation to fluid flow.
• A strong fiber orientation effect was observed near the interfering body's vicinity.
• The method allowed for detailed analysis of rapid orientation changes and combined velocity vector fields with fiber motion.

Conclusions:

• The developed measurement method provides unprecedented insight into flow-induced fiber orientation.
• The random forest algorithm offers an efficient and accurate approach for fiber detection in complex fluids.
• This technique is valuable for optimizing material processing and predicting the performance of fiber-reinforced composites.