Paper Number
NF21 

Session
Non-Newtonian Fluid Mechanics & Instabilities

Title
Understanding viscoelastic suspensions via numerical simulation

Presentation Date and Time
February 16, 2017 (Thursday) 9:05

Track / Room
Track 2 / Audubon A

Authors (Click on name to view author profile)

1. Shaqfeh, Eric S. (Stanford University)
2. Krishnan, Sreenath (Stanford University)
3. Yang, Mengfei (Stanford University)
4. Murch, Will (Stanford University)
5. Iaccarino, Gianluca (Stanford University, Mechanical Engineering)

Author and Affiliation Lines (in printed abstract book)
Eric S. Shaqfeh, Sreenath Krishnan, Mengfei Yang, Will Murch, and Gianluca Iaccarino
Stanford University, Stanford, CA 94305

Speaker / Presenter 
Shaqfeh, Eric S.

Text of Abstract
There are no comprehensive simulation-based tools for engineering the flows of viscoelastic fluid-particle suspensions in fully three-dimensional geometries. On the other hand, the need for such a tool in engineering applications is immense. Suspensions of rigid particles in viscoelastic fluids play key roles in many energy applications and advanced manufacturing applications. In the present work, we describe the development of an Immersed Boundary Method (IB) to simulate the viscoelastic flow in suspensions of nonBrownian spheres. Since the phenomomena of interest occur typically at O(1) values of the flow Weissenberg or Deborah number, we describe the methods necessary to obtain accurate resolution of the stress boundary layers near the particle surface even in the IB framework. Since the code is massively parallel, we demonstrate the simulation of a few hundred particles with the code, and examine in detail two problems where the multi-particle viscoelastic interactions provide unique physical results: 1) The sedimentation of spheres in orthogonal shear in a Taylor Couette Cell and 2) The rheology of a sphere suspension in a viscoelastic fluid in a parallel plate device. We examine these suspensions up to 5% volume fraction and demonstrate that, in each case, the dilute approximation is poor even at very low volume fraction because of the finite Wi wake interactions between particles.