Oscillatory Motion of Rising Bubbles in Wormlike Micellar Fluids with Different Microstructures

Previous observations of the nontransient oscillations of rising bubbles and falling spheres in wormlike micellar fluids were limited to a single surfactant system. We present an extensive survey of rising bubbles in another system, an aqueous solution of cetylpyridinium chloride and sodium salicylate, with and without NaCl, across a range of concentrations and temperatures. Two different types of oscillation are seen in different concentration ranges, each with its own temperature dependence. Rheological data allows for the identification of these different hydrodynamic states with different fluid microstructures.