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# Extensional flow

**Extensional Flow Devices**

My introduction to extensional flow was at Bristol and related to devising apparatus to explore the stretching of polymer chains. Several devices were built during a period of 1970-1976 and are described in the short article below.

Learn more >Bristol Extensional flow Apparatus

The extensional flow story is told in a conference presentation given at a Scientific Meeting in 2009 following the death of Prof P.G deGennes. deGennes was one of Frances leading scientists. He was a good friend of the late Sir Charles Frank and Andrew Keller with whom I worked whilst at Bristol in the 1970s. deGennes would often visit the laboratory at Bristol and spend time with me discussing extensional flow and polymer science. When I moved to Cambridge he would visit Sir Sam Edwards and again we would have polymer discussions.

Learn more >Chamonix1 -09 (v2) (.pdf)

**Extensional flow** has raised its heads in many projects carried out within the Polymer Fluids Group at Cambridge. There are strong elements of extensional flow in the **Oscillatory Flow Mixing (OFM)** work. The **Multipass Rheometer (MPR)** Cross slot facility was specifically developed to examine extensional flow and the **Cambridge Trimaster** is an essentially pure Extensional flow device.

**Publications relevant to extensional flow include**,

- D.G.Crowley, F.C. Frank, M.R. Mackley and R.C. Stephenson. Localised flow birefringence of polyethylene oxide solutions in a four roll mill.. Journal of Polymer Science. A2, 14 , 1111-1119 (1976).
- F.C.Frank and M.R. Mackley. Localized flow birefringence of polyethylene oxide solutions in a two roll mill. Journal of Polymer Science. A2, 14, 1121-1131 (1976).
- M.V.Berry and M.R. Mackley. The six roll mill: Unfolding an unstable persistently extensional flow.. Phil. Trans. Roy. Soc. Lond. 287, 1337, 1-16 (1977).
- M.R.Mackley. Flow singularities, polymer chain extension and hydrodynamic instabilities. Journal of Non-Newtonian Fluid Mechanics. 4, 111-136 (1978).
- M.R.Mackley. Polymer processing; the physics of stretching chains. Physics in Technology. 9, 13-19 (1978).
- M.R.Mackley and I.P.T. Moore. Experimental velocity distribution measurements of high density polyethylene flowing into and within a two dimensional slit. Journal of Non-Newtonian Fluid Mechs. 21, 337-358 (1986).
- S.T.Aldhouse, M.R. Mackley and I.P.T. Moore. Experimental and linear viscoelastic stress distribution measurements of high density polyethylene flowing into and within a two dimensional slit. Journal of Non-Newtonian Fluid Mechs. 21, 359-376 (1986).

distributions of oscillatory flows in baffled tubes. Chem. Eng. Sci. 44, 7, 1471-1479, (1989). - M.R.Mackley.
*Polymer fluids.*Sir Charles Frank Festschrift; Ed. R.G. Chambers et al. Polymer Fluids. Adam Hilger, 307-321 (1991). - R. Liang and M.R. Mackley. Rheological characterisation of the time and strain dependence of polyisbutylene melts. Journal of Non-Newtonian Fluid Mech. 52, 387-405 (1994).
- R. Ahmed and M.R.Mackley. Experimental centreline planar extension of polyethylene. Journal of Non-Newtonian Fluid Mechanics. 56, 2, 127-149 (1995).
- R Ahmed, R Liang and M.R.Mackley. The experimental observation and numerical prediction of planaar entry flow and die swell for molten polyethylene. Journal Non Newtonian Fluid Mech. 59, 2-3, 129-153 (1995).
- M R Mackley & R M C Neves Sariava. The quantitative description of fluid mixing using Lagrangian and concentration based numerical methods. Chem Eng Sci. 54 , 159-170 (1999).
- K. D. Coventry and M. R. Mackley Cross-slot extensional flow birefringence observations of polymer melts using a multi-pass rheometer Journal of Rheology 52, 2, 401-415 (2008)
- D.G.Hassell and M.R.Mackley. Localised flow-induced crystallisation of a polyethylene melt. Rheologica Acta. 47, Nos 9 435-446 (2008)
- D.G. Hassell, D. Auhl, T. C. B. McLeish and M.R.Mackley. The effect of viscoelasticity on stress fields within polyethylene melt flow for a cross-slot and contraction–expansion slit geometry. Rheologica Acta 47, Nos 7 821-834 (2008)
- S. Hoath, I. M.Hutchings, G.D. Martin, T.R.Tuladhar, M.R.Mackley and D. Vadillo
*Links Between Ink Rheology, Drop-on-Demand Jet Formation, and Printability*Journal of Imaging Science and Technology 53, 4, pp. 041208-(1-8) (2009) - L. Scelsi, M. R. Mackley, H. Klein, P. D. Olmsted, R. S. Graham, O. G. Harlen, and T. C. B. McLeish. Experimental observations and matching viscoelastic specific work predictions of flow-induced crystallization for molten polyethylene within two flow geometries Journal of Rheology 53,4, 859-876 (2009)
- D.G. Hassell and M.R Mackley An experimental evaluation of the behaviour of mono and polydisperse polystyrenes in Cross-Slot flow. Rheologica Acta, 48, 5. 543-550 (2009)
- D.G. Hassell, D. Hoyle, D. Auhl, O. Harlen, M.R. Mackley and T. C. B. McLeish Effect of branching in cross-slot flow: the formation of “W cusps”. Rheol Acta 48. 551–561 (2009)
- M.R. Mackley Stretching polymer chains. Rheologica Acta, 49, 5. 443-458 (2010)
- T.D.Lord, L. Scelsi, D.G. Hassell, M.R. Mackley, J. Embery, D Auhl and O.G.Harlen The matching of 3D Rolie-Poly viscoelastic numerical simulations with experimental polymer melt flow within a slit and a cross-slot geometry
*.*Journal of Rheology 54, 2. 355-373 (2010) - D.C. Vadillo, T.R. Tuladhar, A.C. Mulji and M.R. Mackley The rheological characterization of linear viscoelasticity for ink jet fluids using piezo axial vibrator and torsion resonator rheometers. Journal of Rheology, 54, 4. 781-795 (2010 )
- M.R.Mackley and D.G.Hassell The Multipass rheometer; a review Part 1 , Part 2 Journal of Non Newtonian Fluid Mechanics, 166, 9-10, 421-456 (2011)
- D.Auhl, D.M.Hoyle, D.Hassell, T.D.Lord, M.R.Mackley, O.G.Harleen, T.C.B.Mcleish Cross-slot extensional rheometry and steady state extensional response of long chain branched polymer melts. J. Rheology. 55, 875- 901 (2011)
- M. Tembely, D. Vadillo, M. R. Mackley and A. Soucemarianadin The matching of a “one-dimensional” numerical simulation and experiment results for low viscosity Newtonian and non-Newtonian fluids during fast filament stretching and subsequent break-up J. Rheology. 56, 159- 184 (2012)
- D. C. Vadillo, M. Tembely, N.F. Morrison, O. G. Harlen, and M. R. Mackley

The matching of polymer solution fast filament stretching, relaxation, and break up experimental results with 1D and 2D numerical viscoelastic simulation. J. Rheology . 56, 1491-1516 (2012) - M.R.Mackley. Inventing and Developing Scientific Apparatus .British Society of Rheology Bulletin 53, 3 68-80 December (2012)