Hydrodynamic Instability of Fluid Flow Through Homogeneous Porous Media

To examine mechanisms for the production of large-amplitude, steady disturbances at elevated Reynolds number, the effective porosity of the medium is reconsidered. Experimental results and detailed microscale flow simulations indicate that significant regions of flow separation exist around and downstream of the contact points of the particles in the porous medium. This results in a decrease in the effective porosity of the medium as Reynolds number is increased, insofar as transport of mass and momentum are concerned, and this phenomenon has not been addressed in prior experimental or computational studies. A new porosity-based streamfunction transformation is introduced, similar in aspects to the density-based transformations used in compressible flows. The porosity is then assumed to be a function of flow Reynolds number. The equation for the linearized disturbance streamfunction then depends on the derivative of porosity with respect to pore Reynolds number evaluated at the mean flow conditions. Flow in the porous media system is found to be spatially unstable for relatively small negative values of the porosity derivative, thus providing a new potential mechanism for observed instabilities.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Aerospace Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Low, Corwyn Eng Kong

Contributors dc:contributor

• Beddini, Robert A.

• Physics, Fluid and Plasma

Language dc:language

eng

Identifier

(MiAaPQ)AAI9955647

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/85133