1 research outputs found
Gel stability in waves : breakage, behaviour, and implications for oil spill remediation
While oil spills are becoming less common, they are an ever-present threat associated
with use of petroleum. New developments in chemistry have brought gellants
back into the spotlight as a promising spill remediation technique. These chemicals
change the material properties of spilled oil, making it more solid. This could
help prevent the spreading or weathering of spilled oil, extending the window-of-opportunity
available for remediation. While oil-gelling technology shows great
promise, the behaviour of surface gels subject to linear ocean waves has not yet
been investigated. Determining what wave conditions result in the breakup of a
gel layer could help predict the utility of these technologies in the field. This
study adopts an experimental perspective to provide insight into the behaviour of
gels subjected to wave action, specifically addressing the stretching induced by
spatially-variable velocity gradients.
Bottom-of-tank experiments were designed to allow the isolation of wave-induced
stretching effects from wave-induced bending. In these experiments, a
dense gel (gelatin) was placed on the bottom of a wave tank and constrained vertically.
As particle orbits in a shallow-water wave decay vertically with depth, this
is an effective means of applying the same spatial velocity gradients that would
be observed on the water surface. Analytical models were developed to describe
the response of a viscoelastic gel to periodic, spatially-variable velocity gradients
for Maxwell and Kelvin-Voigt materials. The analytical models matched experimental
data in terms of trend, but under-predicted strain by a constant factor. Ultimately,
gel breakage was determined to be related to peak stress across the gel’s
cross-section. By connecting breaking criteria in monochromatic, linear waves
from tank tests to real-world conditions, this project provides an initial perspective
on when wave-induced stretching alone could cause the fracture of a marine
surface gel.Applied Science, Faculty ofCivil Engineering, Department ofGraduat