Pulsating flow of viscoelastic fluids in straight tubes of arbitrary cross-section—Part I: longitudinal field

The pulsating flow of a Green-Rivlin fluid in straight tubes of arbitrary cross-section is investigated. We work with the linearly viscoelastic fluid at the first order of the perturbation of the non-linear constitutive structure defined by a series of nested integrals over semi-infinite time domains. The boundary for the base flow, linearly viscoelastic flow in a circular tube in this case, is perturbed through the application of a novel approach to the concept of domain perturbation to yield a continuous spectrum of closed cross-sectional shapes. The longitudinal component of the flow field is investigated in detail for representative cross-sectional shapes in the spectrum including the square, the triangle and the hexagone, and the velocity profiles are presented for a specific fluid.