Speed Of Shear Waves As a Function Of Frequency In Micellar Fluid

The purpose of this experiment was to investigate the frequency dependence of shear wave speed in a micellar fluid. Micellar fluids consist of an aqueous solution of a surfactant and a salt, and being viscoelastic, support shear waves. A CTAB-NaSal micellar fluid of high concentration seeded with microspheres was used in the experiment. Shear waves were generated using a wave driver and a function generator along with a high-speed camera to capture video recordings. Using the relation c=f𝝀, with the frequency, f, being the frequency of the wave driver and 𝝀 the wavelength, the speed of the wave, can be determined by measuring the wavelengths at different frequencies. The video captured is broken down into frames using Matlab. These frames are uploaded to ImageJ to track microsphere particles vibrating in response to the wave distance between particles in phase with one another. This procedure is done for frequencies of 50 Hz to 130 Hz in increments of 10 Hz and the speed of the wave at each frequency was compared to determine whether the wave speed was frequency-dependent.