Publication: Assessment of the flow characteristics of a dam physical model with anti-vortex structure using computational fluid dynamics
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Date
2023-05-01
Authors
Thiennieesh A/L Manogaran
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Abstract
Dams are structures that are being used to oppose or halt the flow of water in a
stream or river. Unfavourable flow characteristics in the dam can cause problems such
as fluctuation in pressure, loss in discharge capacity as well as problematic flow
conditions in tunnels ad turbines. This research describes the physical modelling
performed on the physical model of a dam reservoir with a distorted scale of 1:100.
Particle Image Velocimetry (PIV) approach was implemented since it has evolved into
one of the most prominent non-intrusive flows measuring techniques and was able to
measure flow parameters such as velocity and discharge which had a good data
agreement with Nixon Streamflow Velocity Meter. Free-surface vortices (FSV) were
also detected through velocity vector instantaneously. CFD modelling enables to analyse
flow patterns in the model, such as free-surface vortices. The model of the 1:100 scale
dam reservoir was generated, computationally meshed, and modelled in FLUENT under
ANSYS 2019 R3 at two different water levels to observe the FSV formations. To
mitigate those FSV formations, anti-vortex plates with two distinct plates—square and
wedge—were used. From the findings square plates outperform wedge plates because
square it lowers the speed of a fast-flowing fluid and reduces it into a laminar flow rather
of a turbulent flow, which benefits vortex class deterioration. Data from the simulation
and experimental shows a strong agreement in terms of velocity less than 20%. From this
study, the modification could be adapted to avoid the FSV formation in the real dam
model when designed under suitable guidelines for vortex structures.