Variational approach for the flow of Ree-Eyring and Casson fluids in   pipes
  The flow of Ree-Eyring and Casson non-Newtonian fluids is investigated using a variational principle to optimize the total stress. The variationally-obtained solutions are compared to the analytical solutions derived from the Weissenberg-Rabinowitsch-Mooney equation and the results are found to be identical within acceptable numerical errors and modeling approximations. 
Taha Sochi
physics.flu-dyn