Electrokinetic Control of Interfacial Instabilities

dc.contributor.advisorBenneker, Anne Maria
dc.contributor.advisorGates, Ian Donald
dc.contributor.authorNwani, Benedicta Nkenchor
dc.contributor.committeememberHassanzadeh, Hassan
dc.contributor.committeememberHejazi, Hossein
dc.contributor.committeememberBryant, Steven
dc.contributor.committeememberDocoslis, Aristides
dc.description.abstractInterfacial instabilities have significant impact on the efficiency of various processes that are present in our surroundings. These instabilities occur due to fluid-fluid interfacial perturbations which could be driven electrically, magnetically, via pressure, surface tension, etc. One of the most frequent occurrences of interfacial instabilities is the displacement of a more viscous fluid by a less viscous one which results in an instability known as ‘viscous fingering’. Controlling viscous fingering is challenging since it occurs at the onset of the displacement and affects the overall displacement pattern observed. Nevertheless, researchers have proposed passive and active control methods to address this issue. The objective of this thesis is to extensively explore the use of electric fields for actively controlling viscous fingering in both miscible and immiscible fluid systems. A combination of experimental and numerical techniques are employed to investigate this phenomenon. The first fluid system examined is immiscible, in which the resident fluid is a perfect dielectric fluid with a preferential wetting on the substrate and no notable fluid-fluid and fluid-wall interfacial charges. The second fluid system involves both miscible and conducting fluids with electro-neutral fluid-fluid interface. The immiscible third fluid system has significant interfacial charges between fluids due to added ionic surfactants in the invading brine, leading to preferential substrate wetting. The results of the first study conducted experimentally, indicated that viscous fingering can be effectively controlled even when one of the fluids is completely non-conductive. Regardless of the magnitude of the applied electric field, positive values stabilized the displacement, while negative values destabilized it. For the miscible fluid system, numerical simulations revealed that the effect of positive or negative electric fields on the displacement (de)-stabilization depended on whether the resident fluid experienced a higher or lower electroosmotic flow under the influence of an electric field. The third study’s experimental results revealed that the presence of the combination of electric field and ionic surfactants dramatically altered the system’s behavior, due to the presence of fluid-fluid interfacial charges that induced electro-Marangoni stresses at the interface when acted upon by an external electric field, which ultimately destabilized the displacement in most cases.
dc.identifier.citationNwani, B. N. (2023). Electrokinetic control of interfacial instabilities (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.
dc.publisher.facultyGraduate Studies
dc.publisher.institutionUniversity of Calgary
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subjectViscous fingering
dc.subjectElectric field
dc.subjectInterfacial tension
dc.subjectComputational fluid dynamics
dc.subjectInterfacial instability
dc.subjectHele-Shaw cell
dc.subjectNumerical modelling
dc.titleElectrokinetic Control of Interfacial Instabilities
dc.typedoctoral thesis
thesis.degree.disciplineEngineering – Chemical & Petroleum
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameDoctor of Philosophy (PhD)
ucalgary.thesis.accesssetbystudentI do not require a thesis withhold – my thesis will have open access and can be viewed and downloaded publicly as soon as possible.
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
52.78 MB
Adobe Portable Document Format
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
2.62 KB
Item-specific license agreed upon to submission