| Flow cavitation is altered substantially, both at inception and during subsequent dynamics, by the addition of small amounts of water soluble polymer. Theoretical and experimental single-bubble systems developed here trace the shape of a bubble as it is influenced by a volume change of the cavity, the rheology of the surrounding fluid, the presence of a solid wall, and/or an imposed external flow.; The theoretical formulation pertains to a bubble in a fluid which is infinite in extent and contains no barriers or interfaces apart from the bubble surface. An external flow can be imposed, imparting a stress history. In addition, a spherical bubble profile, obtained from present experiments or theories, dictates a volume change and drives the nonsphericities.; Surface tension and inertial forces are very important in these bubbles and are incorporated in the model. Because the effects of fluid rheology are of primary interest, the changes in bubble behavior which occur between a Newtonian and non-Newtonian environment are discussed extensively. An integral constitutive expression generates the stress field in the fluid.; Theoretical results show that viscosity and elasticity can be important to cavitation dynamics. Spherical bubble growth and collapse display almost no sensitivity to changes in fluid rheology. The behavior of nonspherical bubbles in an otherwise quiescent fluid is altered significantly by the addition of an elastic component to the constitutive relation, and such changes are even larger when an external flow is imposed.; Optical cavitation techniques generated reproducible cavities in water and dilute polymer solutions. The bubbles were produced spherically or nonspherically, with or without the presence of a solid wall.; Experimental results show good agreement with the theory for nonspherical bubbles in an infinite quiescent fluid. Other trials, near a solid wall suggest the existence of a competition between nonspherical modes. The jet which is induced by a solid wall near an initially spherical bubble does not appear when the bubble is initiated asymmetrically.; Finally, a combination of the external flow theory and experimental observations near a solid wall predicts that changes in rheological properties can macroscopically alter cavitation behavior by changing the influence of the flow on the bubble. This is the first work to put forth a plausible explanation for such an interaction. |
