The dynamics of the coil-stretch transition for long, flexible polymers in planar mixed flows

Brownian dynamics simulations of planar mixed flows of polymer solutions at finite concentrations

“…The length scale l H = √ k B T/H and time scale λ H = ζ/4H (where, k B is the Boltzmann constant, T is the temperature, H is the spring constant and ζ is the hydrodynamic friction coefficient associated with a bead), have been used for the purpose of non-dimensionalising Eq (8). The 3 × 3 tensor κ is equal to (∇v) T , with v being the unperturbed solvent velocity.…”

“…Static and dynamic properties of polymer solutions at equilibrium can be calculated once the trajectories of the time evolution of all the beads on all the chains are obtained using Eq. (8). For rheological properties, not only are the bead configurations required, it is also necessary to know the forces acting on them.…”

“…In many practical situations, however, rather than only shear or elongational flow, a combination of these flows is often observed. A special case is the linear combination of shear and elongational flow, the so-called mixed flow [4][5][6][7][8]. While elongational flows are shear free flows, shear flows have equal contributions from vorticity and elongation.…”

“…Experimentally, mixed flows have been generated and studied using the four-roll mill [9]. While there have been 1 relatively few computational studies of mixed flows of dilute polymer solutions [5][6][7][8], there have been almost no computational studies of polymer solutions at finite concentrations undergoing mixed flow. Such flows are of significant interest in many practical applications, particularly in situations where there is a strong elongational component to the deformation, such as in inkjet printing or fibre spinning [10,11].…”

“…Apart from NEMD simulations, these PBCs have also been implemented in a Brownian dynamics (BD) simulation algorithm by Stoltz et al [16] to simulate semidilute polymer solutions undergoing pla-nar shear and planar elongational flows. In the context of planar mixed flows, Woo and Shaqfeh [6], Dua and Cherayil [7] and Hoffman and Shaqfeh [8] have carried out simulations of dilute polymer solutions using a BD algorithm. However, PBCs are not required in single chain simulations.…”