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Stagnation-point flow of upper-convected maxwell fluids

Sadeghy, K ; Sharif University of Technology | 2006

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  1. Type of Document: Article
  2. DOI: 10.1016/j.ijnonlinmec.2006.08.005
  3. Publisher: 2006
  4. Abstract:
  5. Two-dimensional stagnation-point flow of viscoelastic fluids is studied theoretically assuming that the fluid obeys the upper-convected Maxwell (UCM) model. Boundary-layer theory is used to simplify the equations of motion which are further reduced to a single non-linear third-order ODE using the concept of stream function coupled with the technique of the similarity solution. The equation so obtained was solved using Chebyshev pseudo-spectral collocation-point method. Based on the results obtained in the present work, it is concluded that the well-established but controversial prediction that in stagnation-point flows of viscoelastic fluids the velocity inside the boundary layer may exceed that outside the layer may just be an artifact of the rheological model used in previous studies (namely, the second-grade model). No such peculiarity is predicted to exist for the Maxwell model. For a UCM fluid, a thickening of the boundary layer and a drop in wall skin friction coefficient is predicted to occur the higher the elasticity number. These predictions are in direct contradiction with those reported in the literature for a second-grade fluid. © 2007 Elsevier Ltd. All rights reserved
  6. Keywords:
  7. Boundary layer flow ; Chebyshev approximation ; Equations of motion ; Maxwell equations ; Stream flow ; Viscoelasticity ; Chebyshev pseudo spectral collocation point methods ; Friction coefficient ; Maxwell fluids ; Second grade fluids ; Stagnation point flow ; Upper convected maxwell (UCM) models ; Flow of fluids
  8. Source: International Journal of Non-Linear Mechanics ; Volume 41, Issue 10 , 2006 , Pages 1242-1247 ; 00207462 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0020746207000182