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Abstract: The purpose of this study is to contribute to the knowledge of viscoelastic fluids flows in a contraction which are often studied numerically. A device has been conceived for an experimental study of the flow by Laser Doppler velocimetry. An isothermal flow through a rectangular duct including an abrupt contraction has been considered. We have characterized the isothermal flow for different values of Reynolds number and correlations of the axial velocity are presented. To cite this article: M. Mahfoud et al., C. R. Mecanique 336 (2008). [Copyright &y& Elsevier]

This paper is concerned with incompressible viscoelastic fluids which obey a differential constitutive law of White–Metzner type. We establish the existence and uniqueness of local solutions in 3-D as well as the global existence of small solutions. We then deduce the existence and asymptotic stability of small periodic and stationary solutions. Finally, we prove that the 2-D results obtained in Hakim (J. Math. Anal. Appl. 185 (1994) 675–705) remain true without any restriction on the smallness of the retardation parameter which is the linking coefficient between the equation of velocity (Navier–Stokes equation) and the transport equation verified by the extra-stress tensor. To cite this article: L. Molinet, R. Talhouk, C. R. Acad. Sci. Paris, Ser. I 338 (2004). [Copyright &y& Elsevier]