Browsing by Subject "Yield stress"

Now showing items 1-20 of 29

    • Article  

      Cessation of annular Poiseuille flows of Bingham plastics 

      Chatzimina, Maria Evangelia; Xenophontos, Christos A.; Georgiou, Georgios C.; Argyropaidas, Ioannis; Mitsoulis, Evan C. (2007)
      We numerically solve the cessation of the annular Poiseuille flow of Bingham plastics for various values of the diameter ratio, using the regularized constitutive equation proposed by Papanastasiou and employing finite ...
    • Article  

      Cessation of Couette and Poiseuille flows of a Bingham plastic and finite stopping times 

      Chatzimina, Maria Evangelia; Georgiou, Georgios C.; Argyropaidas, Ioannis; Mitsoulis, Evan C.; Huilgol, R. R. (2005)
      We solve the one-dimensional cessation Couette and Poiseuille flows of a Bingham plastic using the regularized constitutive equation proposed by Papanastasiou and employing finite elements in space and a fully implicit ...
    • Article  

      Cessation of Newtonian circular and plane Couette flows with wall slip and non-zero slip yield stress 

      Philippou, Maria; Damianou, Y.; Miscouridou, X.; Georgiou, Georgios C. (2017)
      We solve analytically the cessation flows of a Newtonian fluid in circular and plane Couette geometries assuming that wall slip occurs provided that the wall shear stress exceeds a critical threshold, the slip yield stress. ...
    • Article  

      Cessation of viscoplastic Poiseuille flow in a square duct with wall slip 

      Damianou, Y.; Kaoullas, G.; Georgiou, Georgios C. (2015)
      We solve numerically the cessation of the pressure-driven Poiseuille flow of a Bingham plastic under the assumption that slip occurs along the wall following a generalized Navier-slip law involving a non-zero slip yield ...
    • Article  

      Cessation of viscoplastic Poiseuille flow with wall slip 

      Damianou, Y.; Philippou, Maria; Kaoullas, G.; Georgiou, Georgios C. (2014)
      We solve numerically the cessation of axisymmetric Poiseuille flow of a Herschel-Bulkley fluid under the assumption that slip occurs along the wall. The Papanastasiou regularization of the constitutive equation is employed. ...
    • Article  

      Combined effects of compressibility and slip in flows of a Herschel-Bulkley fluid 

      Damianou, Y.; Georgiou, Georgios C.; Moulitsas, I. (2013)
      In this work, the combined effects of compressibility and slip in Poiseuille flows of Herschel-Bulkley fluids are investigated. The density is assumed to obey a linear equation of state, and wall slip is assumed to follow ...
    • Article  

      Determination of the rheological parameters of self-compacting concrete matrix using slump flow test 

      Neophytou, Marina K. A.; Pourgouri, Stella; Kanellopoulos, Antonios D.; Petrou, Michael F.; Ioannou, Ioannis; Georgiou, Georgios C.; Alexandrou, Andreas N. (2010)
      The classification of a concrete mixture as self-compacting (SCC) is performed by a series of empirical characterization tests that have been designed to assess not only the flowability of the mixture but also its segregation ...
    • Article  

      Determination of the rheological parameters of self-compacting concrete matrix using slump flow test 

      Neophytou, Marina K. A.; Pourgouri, S.; Kanellopoulos, A. D.; Petrou, Michael F.; Ioannou, I.; Georgiou, G.; Alexandrou, Andreas N. (2010)
      The classification of a concrete mixture as self-compacting (SCC) is performed by a series of empirical characterization tests that have been designed to assess not only the flowability of the mixture but also its segregation ...
    • Article  

      Inertial, viscous and yield stress effects in Bingham fluid filling of a 2-D cavity 

      Alexandrou, Andreas N.; Duc, E.; Entov, V. (2001)
      The present study concentrates on Bingham fluid filling of a 2-D cavity and examines the relative importance of inertial, viscous and yield stress effects on the filling profile. The results presented are obtained using ...
    • Article  

      Newtonian flow in a triangular duct with slip at the wall 

      Georgiou, Georgios C.; Kaoullas, G. (2013)
      We consider the Newtonian Poiseuille flow in a tube whose cross-section is an equilateral triangle. It is assumed that boundary slip occurs only above a critical value of the wall shear stress, namely the slip yield stress. ...
    • Article  

      Newtonian Poiseuille flows with slip and non-zero slip yield stress 

      Kaoullas, G.; Georgiou, Georgios C. (2013)
      The Newtonian Poiseuille flow is considered for various geometries, under the assumption that wall slip occurs above a critical value of the wall shear stress known as, the slip yield stress. In the axisymmetric and planar ...
    • Article  

      Numerical study of the combined effects of inertia, slip, and compressibility in extrusion of yield stress fluids 

      Kountouriotis, Zacharias; Georgiou, Georgios C.; Mitsoulis, Evan C. (2014)
      The axisymmetric extrudate swell flow of a compressible Herschel–Bulkley fluid with wall slip is solved numerically. The Papanastasiou-regularized version of the constitutive equation is employed, together with a linear ...
    • Article  

      On the early breakdown of semisolid suspensions 

      Alexandrou, Andreas N.; Georgiou, Georgios C. (2007)
      Semisolid materials are suspensions of metal alloys which are processed while in a mushy state. In this state, the suspensions behave as viscoplastic materials with time-dependent material properties. During processing, ...
    • Article  

      On the early breakdown of semisolid suspensions 

      Alexandrou, Andreas N.; Georgiou, G. (2007)
      Semisolid materials are suspensions of metal alloys which are processed while in a mushy state. In this state, the suspensions behave as viscoplastic materials with time-dependent material properties. During processing, ...
    • Article  

      On the modeling of semisolid suspensions 

      Alexandrou, Andreas N. (2008)
      Due to the distinct rheology of semisolid slurries the process has well established advantages over competing near-net-shape manufacturing technologies. Despite the obvious advantages of the process its adoption by the ...
    • Article  

      Predictions of structure breakdown, buildup and shear banding in semisolid suspensions 

      Alexandrou, Andreas N.; Constantinos, N.; Georgiou, Georgios C. (2008)
      When SSM material is subjected to a sudden transient the rate of buildup (aging) is negligible compared to the rate of breakdown (shear rejuvenation). While this is generally true, due to prolonged processing or the geometry ...
    • Article  

      Predictions of structure breakdown, buildup and shear banding in semisolid suspensions 

      Alexandrou, Andreas N.; Constantinos, N.; Georgiou, G. (2008)
      When SSM material is subjected to a sudden transient the rate of buildup (aging) is negligible compared to the rate of breakdown (shear rejuvenation). While this is generally true, due to prolonged processing or the geometry ...
    • Article  

      Shear rejuvenation, aging and shear banding in yield stress fluids 

      Alexandrou, Andreas N.; Constantinou, N.; Georgiou, Georgios C. (2009)
      The purpose of this work is to simulate shear rejuvenation and aging effects in shear thinning yield stress fluids in a typical rotational rheometer and to provide a common framework to describe the behavior of yield stress ...
    • Article  

      Shear rejuvenation, aging and shear banding in yield stress fluids 

      Alexandrou, Andreas N.; Constantinou, N.; Georgiou, G. (2009)
      The purpose of this work is to simulate shear rejuvenation and aging effects in shear thinning yield stress fluids in a typical rotational rheometer and to provide a common framework to describe the behavior of yield stress ...
    • Article  

      Squeeze flow of thixotropic semisolid slurries 

      Alexandrou, Andreas N.; Florides, G. C.; Georgiou, Georgios C. (2014)
      An essential element for the integration of a semisolid process in the production of complex commercial components is the availability of accurate mathematical and computational tools that could describe both the rheological ...