Measurement of Low Flow Velocity by Dynamic Light Scattering

Laser-Doppler velocimetry is a standard technique of measuring velocity in flowing dispersion. However, it might not be ideal for the study with low flow velocity, which is inevitable in many applications, such as pulpal blood flow measurement in both humans and experimental animals. In this paper, we are based our sinc model on dynamic light scattering technique analyzing data in correlation time domain instead of frequency domain, at which we take Brownian motion into account, contributing to minimum theoretical measured velocity, e.g., 0.001 mm/s for larger particles. The model agrees well with the experimental results and has higher measurement accuracy than the traditional Laser-Doppler velocimetry. We believe our model can complement established methods and pave the way for the complex fluid system measurements, such as the on-line measurement in the flowing dispersion.