Multiscale analysis of flows past marine hydrokinetic devices using numerical simulations
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Date
2021
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Abstract
In this work, we seek to understand the effects that a farm of Marine Hydrokinetic
(MHK) devices would have on the
flow in the Chacao channel, Chile. We adopted a
multi-scale approach to study the
ow at the turbine scales and propose a parameterization
for representing a group of turbines in the mesoscale. In Chapter II, we used
the hybrid turbulence model DES coupled with the actuator disk approach to simulate
staggered turbine con gurations with different separations between devices and
channel depths on an idealized domain. Using the time-averaged results, we obtained
an expression for a new thrust coefficient representative of an entire farm of turbines,
CtF arm, which only depends on the lateral and longitudinal separation of the devices
and the number of rows of turbines. In Chapter III, we incorporated CtF arm into the
ocean circulation model FVCOM, representing a speci c nite farm of turbines in the
Chacao channel. Firstly, we simulated a base case without devices to choose three
suitable locations for installing a farm of turbines according to a commercial device's
speci cations. Then, we characterized the local bathymetry of the chosen locations
to design an appropriate computational grid that considers the dominant bedforms.
After simulating turbines, we observe variations in the velocity, turbulent kinetic energy
(TKE), and shear bottom since these factors could affect the local ecosystem.
The results showed that in
fiatter bathymetries, the magnitude of the percentage
change in TKE and bottom shear is higher than in complex bathymetries since the
presence of turbines represents a more signi cant alteration of the initial conditions.
On the other hand, the absolute changes show that the initial conditions in velocity
and TKE dominate the momentum extraction despite the bedforms because they
have more power available. In this research, we were able to take the thrust force of
a specifi c farm of turbines using high-resolution simulations and bring it to a larger
scale model with realistic tides and bathymetries, which provides more insights to
predict and mitigate the possible negative impacts of an MHK farm installation.
Description
Tesis (Doctor in Engineering Sciences)--Pontificia Universidad Católica de Chile, 2021
Tesis (Doctor of Philosophy)--University of Notre Dame, 2021
Tesis (Doctor of Philosophy)--University of Notre Dame, 2021