title: Convective-to-absolute instability transition in a viscoelastic capillary jet subject to unrelaxed axial elastic tension.
abstract: The convective-to-absolute instability transition in an Oldroyd-B capillary jet subject to unrelaxed axial stress is examined theoretically. There is a critical Weber number below which the jet is absolutely unstable under axisymmetric perturbations. We analyze the dependence of this critical parameter with respect to the Reynolds and Deborah numbers, as well as the unrelaxed axial stress. For small Deborah numbers, the unrelaxed stress destabilizes the viscoelastic jet, increasing the critical Weber number for which the convective-to-absolute instability transition takes place. If the Deborah number takes higher values, then the transitional Weber number decreases as the unrelaxed stress increases until two solution branches cross each other. The dominant branch for large axial stress leads to a threshold of this quantity above which the viscoelastic jet becomes absolutely unstable independently of the Weber number. The threshold depends on neither the Reynolds nor the Deborah number for sufficiently large values of these parameters.
authors.affiliation: Escuela Superior de Ingenieros, Universidad de Sevilla, Camino de los Descubrimientos s/n, E-41092 Sevilla, Spain.
authors.forename: A Said
authors.initials: AS
authors.lastname: Mohamed
authors.affiliation: Escuela Superior de Ingenieros, Universidad de Sevilla, Camino de los Descubrimientos s/n, E-41092 Sevilla, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Herrada
authors.affiliation: Escuela Superior de Ingenieros, Universidad de Sevilla, Camino de los Descubrimientos s/n, E-41092 Sevilla, Spain.
authors.forename: A M
authors.initials: AM
authors.lastname: Gañán-Calvo
authors.affiliation: Departamento de Ingeniería Mecánica, Energética y de los Materiales and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, E-06006 Badajoz, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Montanero
mesh_terms: D018481:Convection; D004548:Elasticity; D008962:Models, Theoretical; D055682:Viscoelastic Substances
chemical_list: D055682:Viscoelastic Substances