|dc.contributor.advisor||Van Den Bremer, Ton||en
|dc.contributor.author||Kreitmair, Monika Johanna||en
|dc.description.abstract||In river and tidal stream power assessment, uncertainties arise from model
assumptions and the inexact specification of physical and numerical model parameters.
Combined, such uncertainties can greatly affect power estimates for
a given site. The thesis examines the effects of bed roughness and turbine drag
uncertainties on turbine power estimates.
An analytic model is developed for transfer of bed friction uncertainty to
power extracted from turbines in a strait, representative of a river. A validated
finite volume solver of the shallow water equations is developed and applied to
simulate flow driven by a constant head difference through a one-dimensional
strait. The presence of a turbine fence is included using enhanced bed friction.
A parameter study examines the effect of uncertainty propagation from bed
friction to power. Excellent agreement is obtained between the analytic and
numerical power uncertainty estimates for a given input bed friction PDF.
Perturbation methods are used to determine the leading-order effect of bottom
friction uncertainty in tidal stream power assessment. The theoretical
models consider quasi-steady flow in a channel completely spanned by tidal turbines,
a similar channel but retaining the inertial term, and a circular turbine
farm in laterally unconfined flow. It is found that changes to expected power
depend on the dynamic balance in the channel, the turbine configuration, and
the geometry of the site considered. Bottom friction uncertainty increases estimates
of expected power in a fully-spanned channel, but has the reverse effect
in laterally unconfined farms. The optimal number of turbines under bottom
friction uncertainty is lower for a fully-spanned channel and higher in laterally
unconfined farms. The effect of uncertainty in turbine drag is also considered.
A standard methodology is presented for uncertainty propagation using general
computational models. The methodology is tested using a shallow flow
model of the Pentland Firth, where power statistics are determined according
to input bed friction probability distribution, and the results compared against
those from the (simplified) analytic perturbation approaches. Although the analytic
models for channels perform reasonably well regarding the estimate of
expected power, the predictions from the unconfined analytic model were not
so satisfactory owing to the model assumptions.
The methods for uncertainty transfer presented in the thesis could readily
be applied to many other problems encountered in hydraulic engineering, such
as river flow routing, urban flood risk, reservoir sedimentation, etc.||en
|dc.contributor.sponsor||Engineering and Physical Sciences Research Council (EPSRC)||en
|dc.publisher||The University of Edinburgh||en
|dc.relation.hasversion||Kreitmair M. J., Borthwick A. G. L., and van den Bremer T. S. (2017). Effect of bed roughness uncertaintyon tidal stream power estimates. Proceedings of the 12th European Wave and Tidal Energy Conference (EWTEC), Cork, Ireland.||en
|dc.relation.hasversion||Kreitmair M. J., Borthwick A. G. L., van den Bremer T. S., and Draper S. (2018). The effects of uncertain bottom friction on estimates of tidal current power. Proceedings of the 6th Oxford Tidal Energy Workshop, Oxford, United Kingdom.||en
|dc.relation.hasversion||Kreitmair M. J., Draper S., Borthwick A. G. L., and van den Bremer T. S. (2019). The effect of uncertain bottom friction on estimates of tidal current power. Royal Society Open Science, 6(1):180941.||en
|dc.relation.hasversion||Kreitmair M. J., Borthwick A. G. L., and van den Bremer T. S. (2019). Uncertainty Quantification for Tidal Power in the Pentland Firth. Proceedings of the 15th Young Coastal Scientists and Engineers Conference, Glasgow, United Kingdom.||en
|dc.subject||bed roughness coefficient||en
|dc.subject||tidal energy resource assessment||en
|dc.title||Uncertainty quantification in tidal energy resource assessment||en
|dc.type||Thesis or Dissertation||en
|dc.type.qualificationname||PhD Doctor of Philosophy||en