Bio-inspired all-optical artificial neuromast for 2D flow sensing.

Area of Science:

• Biomimetic sensors
• Optical fluid dynamics
• Photonics instrumentation

Background:

• The fish lateral line system provides a biological model for sensing fluid motion.
• Existing flow sensors often lack sensitivity or directional capabilities.

Purpose of the Study:

• To design and fabricate an all-optical 2D flow velocity sensor inspired by the biological neuromast.
• To demonstrate the sensor's capability for accurate fluid flow speed and direction measurement.

Main Methods:

• Fabrication of an artificial neuromast using optical fibers with Bragg gratings and a fluid force recipient sphere.
• Modeling the sensor's dynamic response using the Stokes solution for unsteady flow.
• Experimental validation of the sensor's performance and deconvolution scheme for data retrieval.

Main Results:

• The sensor's dynamic response agrees with theoretical models.
• Achieved a low-frequency threshold flow sensing of 5 mm s⁻¹ and 5 μm s⁻¹ at resonance.
• Demonstrated a linear dynamic range of 38 dB at 100 Hz sampling.
• Accurate determination of flow direction within a few degrees.

Conclusions:

• The developed optical artificial neuromast is a sensitive and accurate flow velocity sensor.
• The biomimetic design enables precise measurement of both speed and direction in 2D flow.
• This technology holds potential for various fluid dynamics applications.