Micro and Complex Flows

Introduction

Phenomena such as wetting, phase change (boiling), fluid-structure interaction and particle or droplet behaviour (e.g. rotation, agglomeration, coalescense) are at the core of many flow situations. The FLOW group on Micro Complex Flows perform experimental, numerical and to some extent theoretical studies ranging from the molecular-, nano- or microscale phenomena to milli- or meter-sized flow effects. The work is of a fundamental nature with a constant eye on a wide range of applications such as processing of food or materials, blood flow, energy conversion, etc.

Research overview

Multiphase flows with interfaces including wetting and phase change

The work ranges from modelling, simulations and experiments on small-scale wetting on structured surfaces to large scale simulations of turbulent flows with droplets and particles. We aim at developing increased knowledge of wetting phenomena and capillary through simulations and experiments and include this knowledge in large scale flow simulations and characterise integral effects.

Particle suspensions and non-Newtonian fluids

The particles we study range from nano-fibrils, either ideal stiff particles of biological materials made of proteins or cellulose, via fibre suspensions to millimeter sized spheres and ellipsoids. At all levels, numerical and experimental efforts are combined. We perform world-leading coupled flow- and particle simulations from laminar microfluidic flows via sedimentation to turbulent pipe- and duct flows of particle suspensions in both Newtonian and non-Newtonian fluids. The results are verified by our own experiments. We aim at developing into more complex particle models and flow situation as well as developing experimental techniques.

Fluid structure interactions and poroelastic boundaries

An exciting new development is to couple deformation of and flow inside poroelastic boundary materials inspired by nature (furs, shark skin, butterfly wings) with large scale flow effects. The challenges are to model the elastoporousporoelastic material, couple the boundary to the flow domain and identify interesting flow cases that allow both numerical and experimental studies. 

• To use multiscale methods to model anisoptropic poroelastic beds of fibers, brushes, carpets and their interaction with nearby free flowing flows.
• To extend multiscale models to include multi-phase surfaces (oil-lubricated surface, air-retention)
• To fabricate microstructured surfaces using lithographic techniques and/or 3D printing and characterize the fluid-structure interaction with vortical and turbulent free flows.

Research environment

The group collects expertise in numerical methods, experiments, modelling and simulations. We aim at identifying complex flow situations and

Research groups

• Group of Luca Brandt

• Group of Anna-Karin Tornberg

• Group of Daniel Söderberg and Fredrik Lundell

• Group of Shervin Bagheri

• Group of Lisa Prahl

Facilities

• The group has access to excellent measurement instruments such as MRI, OCT, PIV, microscoped and high speed cameras (up to 10 Mfps), a selection of flow setups (turbulent water table, soap film, square duct, pipe, micro-fluidic channels).

• Several simulation codes

• FLOW centre has access to the different super-computer resources managed by the Swedish Centre for Infrastructures ( SNIC ).

Collaborating organizations

DESY (synchrotron measurements), University of Tokyo, Tohoku University, George Washington University, University of Cincinnati, Cincinnati Children’s hospital, Karolinska University Hospital

Key publications

Stevin van Wyk, Lisa Prahl Wittberg, Kartik V. Bulusu, Laszlo Fuchs, and Michael W. Plesniak, Non-Newtonian perspectives on pulsatile blood-analog flows in a 180° curved artery model, Physics of Fluids 27, 071901 (2015); doi: 10.1063/1.4923311

Lisa Prahl Wittberg, Stevin van Wyk, Laszlo Fuchs, Ephraim Gutmark, Philippe Backeljauw, Iris Gutmark-Little, Effects of aortic irregularities on blood flow, Biomech Model Mechanobiol (2016) 15:345–360

Gabriel Fuchs, Niclas Berg, Anders Eriksson, Lisa Prahl Wittberg, Detection of thrombosis in the ECMO circuit by infrasound - A proof of concept, Artificial Organs (2016) 10.1111/aor.12782

A framework for computing effective boundary conditions at the interface between free fluid and a porous medium, Lacis & Bagheri, JFM 2017

Passive appendages generate drift through symmetry breaking, Lācis, Brosse, Ingremeau, Mazzino, Lundell, Kellay & Bagheri
Nature Comm. vol. 5, pp. 5310, 2014