Picture of industrial chimneys polluting horizon

Open Access research shaping international environmental governance...

Strathprints makes available scholarly Open Access content exploring environmental law and governance, in particular the work of the Strathclyde Centre for Environmental Law & Governance (SCELG) based within the School of Law.

SCELG aims to improve understanding of the trends, challenges and potential solutions across different interconnected areas of environmental law, including capacity-building for sustainable management of biodiversity, oceans, lands and freshwater, as well as for the fight against climate change. The intersection of international, regional, national and local levels of environmental governance, including the customary laws of indigenous peoples and local communities, and legal developments by private actors, is also a signifcant research specialism.

Explore Open Access research by SCELG or the School of Law. Or explore all of Strathclyde's Open Access research...

Optimised cross-slot microdevices for homogeneous extension

Galindo-Rosales, Francisco J and Oliveira, Monica and Alves, M.A. (2014) Optimised cross-slot microdevices for homogeneous extension. RSC Advances, 4 (15). pp. 7799-7804. ISSN 2046-2069

[img] PDF (Oliveira-etal-RSCAdv-2014-Optimized-cross-slot-microdevices-for-homogeneous-extension-2014)
Oliveira_etal_RSCAdv_2014_Optimized_cross_slot_microdevices_for_homogeneous_extension_2014.pdf
Accepted Author Manuscript

Download (3MB)

Abstract

Microfluidic cross-slot devices can generate wide regions of vorticity-free strong extensional flow near the stagnation point, resulting in large extensional deformation and orientation of the microstructure of complex fluids, with possible applications in extensional rheometry and hydrodynamic stretching of single cells or molecules. Standard cross-slot devices, with sharp or rounded corners, generate a flow field with a non-homogeneous extension rate that peaks at the stagnation point, but decays significantly with distance from the stagnation point. To circumvent this limitation, an optimized shape cross-slot extensional rheometer (OSCER) was designed numerically and shown to generate constant extension rate over a wide region of the in- and out-flowing symmetry planes [Haward et al., Phys. Rev. Lett., 2012, 109, 128301]. Since the OSCER device was based on a 2D flow approximation, the practical implementation requires a large aspect ratio, which cannot be reproduced by standard soft-lithography techniques. Here, we propose a set of new designs for optimized cross-slot geometries, considering aspect ratios of order 1 and different lengths of the homogeneous inlet/outlet-flow regions. Micro-particle image velocimetry experiments were carried out in order to validate the flow kinematics, and the velocity profiles were found to be linear along the in- and outflow centrelines in good quantitative agreement with the numerical predictions.