<html aria-label="message body"><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: HelveticaNeue;"><font face="HelveticaNeue">Dear Soft Matter & Complex Systems Colleagues and Friends,</font></div><div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: HelveticaNeue;"><font face="HelveticaNeue"><br></font></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: HelveticaNeue;"><font face="HelveticaNeue">On Friday 16 January 2026 at 9:30 AM at the UW Faculty of Physics (Pasteura 5, Warsaw; room 1.40) we are hosting a seminar, during which </font></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: HelveticaNeue;"><font face="HelveticaNeue"><br></font></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); margin: 0px; line-height: normal; min-height: 14px;"><font face="HelveticaNeue" style="font-family: HelveticaNeue;"><b>Piotr Zdybel </b>(IPPT PAN</font><font face="HelveticaNeue">)</font></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: HelveticaNeue; margin: 0px; line-height: normal; min-height: 14px;"><font face="HelveticaNeue"><br></font></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: HelveticaNeue; margin: 0px; line-height: normal;"><font face="HelveticaNeue">will give a talk</font></div><div style="margin: 0px; line-height: normal; min-height: 14px;"><div><h2 style="margin: 6px 0px 12px; padding: 0px;"><font color="#000000" face="HelveticaNeue"><span style="caret-color: rgb(0, 0, 0); font-size: 12px;">Three-Dimensional Buckling of Slender Filaments in Shear Flow</span></font></h2><h2 style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); margin: 6px 0px 12px; padding: 0px;"><b style="font-family: HelveticaNeue; caret-color: rgb(234, 234, 234);"><font face="HelveticaNeue" style="font-size: 12px;">Abstract</font></b></h2></div><div><div><font color="#000000"><span style="caret-color: rgb(0, 0, 0);">We study the onset of 3D buckling of a slender elastic filament in a viscous shear flow at low Reynolds number and high Péclet number. Using the Euler–Bernoulli (elastica) description linearized about a straight configuration of arbitrary orientation, we show that the 3D stability problem can be reduced to a universal spectral problem governed by an orientation-dependent combination of the elastoviscous number and the shear geometry. Building on earlier in-plane eigenmodes, we solve the 3D eigenproblem and propose a simple analytic approximation of the unstable eigenfunctions as Gaussian wave packets. This yields the central scaling result: for highly flexible filaments, the characteristic wavenumber of the most unstable mode grows proportionally to the square root of this elastoviscous measure. Finally, we validate the predicted eigenshapes by numerical simulations of finite-thickness filaments using a bead model and the HYDROMULTIPOLE codes. The talk is based on our paper: P. Sznajder, P. Zdybel, L. Liu, and M. L. Ekiel-Jeżewska, <i>Phys. Rev. E</i> <b>110</b>, 025104 (2024).</span></font></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0);"><br></div></div></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: HelveticaNeue; margin: 0px; line-height: normal;"><font face="HelveticaNeue">We warmly welcome everyone to attend the talk and the Soft Matter Coffee Break after the seminar, held in room 2.63 (2nd floor).</font></div></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: HelveticaNeue;"><font face="HelveticaNeue"><br></font></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: HelveticaNeue;"><div dir="auto" style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div style="margin: 0px; line-height: normal;"><font face="HelveticaNeue">Maria Ekiel-Jeżewska</font></div><div style="margin: 0px; line-height: normal;"><font face="HelveticaNeue">Maciej Lisicki</font></div><div style="margin: 0px; line-height: normal;"><font face="HelveticaNeue">Piotr Szymczak</font></div><div style="margin: 0px; line-height: normal;"><font face="HelveticaNeue">Panagiotis Theodorakis</font></div></div></div>
<br></body></html>