Dynamics of a flexible polymer in planar mixed flow

TL;DR

This paper derives exact correlation functions for a Rouse polymer in planar mixed flow and investigates the tumbling time distribution, highlighting the limitations of previous methods and providing new estimates for tumbling dynamics.

Contribution

It provides exact spatio-temporal correlation functions for a Rouse polymer in mixed flow and analyzes the tumbling time distribution, extending understanding beyond simple shear flow.

Findings

Exact correlation functions for Rouse polymer in mixed flow

Failure of previous methods for general mixed flow

New estimates for tumbling time distribution exponent

Abstract

We present exact spatio-temporal correlation functions of a Rouse polymer chain submerged in a fluid having planar mixed flow, in the steady state. Using these correlators, determination of the time scale distribution functions associated with the first-passage tumbling events is difficult in general; it was done recently in Phys. Rev. Lett.,101, 188301 (2008), for the special case of "simple shear" flow. We show here that the method used in latter paper fails for the general mixed flow problem. We also give many new estimates of the exponent $\theta$ associated with the exponential tail of the angular tumbling time distribution in the case of simple shear