Research

Dr. Powell’s research focuses on rheology, biorheology, ultrasonics and suspension mechanics. Suspension dynamics is being studied by using magnetic resonance (NMR) imaging. Macroscopic rheological properties of suspensions of spherical and rod-like particles are also under investigation. Suspensions of multisized spherical particles are under review theoretically and experimentally. He carries out biorheological studies to elucidate the mechanical interactions between spermatozoa and their environment. Experimental and theoretical investigations are showing that low concentrations of a polymer additive in water can dramatically alter nonlinear wave propagation in viscoelastic fluids. He extends this work to a wide range of non-Newtonian fluids.

Selected Publications

• D' Avila, M.A., N.C. Shipley, J.H. Walton, R.J. Phillips, S.R. Dungan and R.L. Powell. 2004. Magnetic resonance imaging (MRI): A technique to study flow and microstructure of concentrated emulsions. Brazilian Journal of Chemical Engineering 22:49-60.

• Uludag, Y., M.J. McCarthy and R.L. Powell. 2004. Effects of flow periodic fluctuations on magnetic resonance  flow images. American Institute of Chemical Engineers Journal 50:1662-1671.

• Dogan, N., M.J. McCarthy and RL Powell. 2005. Measurement of polymer melt rheology using ultrasonics-based in-line rheometry. Measurement Science and Technology 16:1684-1690.

• Dogan, N., M.J. McCarthy and R.L. Powell. 2005. Application of an in-line rheological characterizations method to chemically modified and native corn starch. Journal of Texture Studies 36:237-254.

• Stickel, J.J. and R.L. Powell. 2005. Fluid mechanics and rheology of dense suspensions.  Annual Reviews of Fluid Mechanics 37:129-149.