Poiseuille flow of Carreau‐Yasuda fluid at variable pressure gradient

The unsteady Poiseuille flow of Carreau‐Yasuda fluid in a pipe, caused by a variable pressure gradient, is studied theoretically. As a special case, the steady flow is considered separately. It is proved that at some values of the viscosity model parameters, the problem has a generalized solution, while at others ‐ a classical solution. For the latter, a necessary and sufficient condition is found, which depends on the maximum pressure gradient and the Carreau‐Yasuda model parameters.