• Bubble Growth From First Principles 

      Saengow, Chaimongkol; Giacomin, A. Jeffrey; Wu, Xianghong; Kolitawong, Chanyut; Aumnate, Chuanchom; Mix, Adam W. (2016-07-05)
      We consider the simplest relevant problem in the foaming of molten plastics, the growth of a single bubble in a sea of highly viscous Newtonian fluid, and without interference from other bubbles. This simplest problem has ...
    • Exact Analytical Solution for Large-Amplitude Oscillatory Shear Flow 

      Saengow, Chaimongkol; Giacomin, A. Jeffrey; Kolitawong, Chanyut (2015-03-16)
      When polymeric liquids undergo large-amplitude shearing oscillations, the shear stress responds as a Fourier series, the higher harmonics of which are caused by fluid nonlinearity. Previous work on large-amplitude oscillatory ...
    • Exact Analytical Solution for Large-Amplitude Oscillatory Shear Flow from Oldroyd 8-Constant Framework: Shear Stress 

      Saengow, Chaimongkol; Giacomin, A. Jeffrey; Kolitawong, Chanyut (2017-01)
      The Oldroyd 8-constant model is a continuum framework containing, as special cases, many important constitutive equations for elastic liquids. When polymeric liquids undergo large-amplitude oscillatory shear flow, the shear ...
    • Extruding Plastic Pipe From Eccentric Dies 

      Saengow, Chaimongkol; Giacomin, A. Jeffrey; Kolitawong, Chanyut (2015-05-25)
      To solidify plastic pipe, the pipe is transported through a long cooling chamber. Inside this chamber, inside the pipe, the plastic remains molten, and this inner surface solidifies last. The flow due to the self-weight ...
    • Knuckle Formation From Melt Elasticity in Plastic Pipe Extrusion 

      Saengow, Chaimongkol; Giacomin, A. Jeffrey; Kolitawong, Chanyut (2016-07)
      When plastic pipe is solidified, it proceeds through a long cooling chamber. Inside the chamber, inside the extrudate, the plastic is molten, and this inner surface solidifies last. Sag then happens inside this cooling ...
    • Padé Approximants for Large-Amplitude Oscillatory Shear Flow 

      Giacomin, A. Jeffrey; Saengow, Chaimongkol; Guay, Martin; Kolitawong, Chanyut (2015-03-17)
      Analytical solutions for either the shear stress or the normal stress differences in large-amplitude oscillatory shear flow, both for continuum or molecular models, often take the form of the first few terms of a power ...
    • Plastic Pipe Solidification: Exact Solutions in Cylindrical Coordinates 

      Saengow, Chaimongkol; Poungthong, P.; Kolitawong, Chanyut; Giacomin, A. Jeffrey (2015-12)
      For polymer melt solidification in plastic pipe extrusion, we perform an energy balance on the pipe extrudate in cylindrical coordinates to arrive at exact solutions for the temperature, and for the solidification rate. ...
    • Reflections on Inflections 

      Saengow, Chaimongkol; Giacomin, A. Jeffrey; Gilbert, Peter H.; Kolitawong, Chanyut (2015-11-11)
      In plastics processing, the single most important rheological property is the steady shear viscosity curve: the logarithm of the steady shear viscosity versus the logarithm of the shear rate. This curve governs the volumetric ...