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.