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Problem Specification
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h2. Problem Specification {float}[!existing design of sedimentation tank.jpg|width=50,height=100!|CFD Sedimentation Tank Simulation] {float} h4. |
Existing
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Design
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In
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the
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latest
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design
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of
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sedimentation
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tank,
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we
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use
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a
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V-shaped
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tank
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bottom
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to
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collect
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and
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drain
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the
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settled
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flocs,
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with
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influent
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pipes
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installed
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along
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the
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slopes.
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Changes
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and Challenges
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Challenges {float} [!sedimentation tank manifold design.jpg|width=50,height=100!|CFD Sedimentation Tank Simulation] {float} |
In
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a
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newly
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proposed
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design,
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we
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will
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make
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better
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use
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of
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the
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space
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under
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the
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surface
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of
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V-shaped
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bottom,
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replacing
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the
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concrete
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with
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void
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space
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for
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influent
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water,
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and
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create
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water
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inlet
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at
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the
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bottom
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of
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the
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slopes.
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In
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this
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new
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design,
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we
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use
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less
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concrete
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and
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less
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pipes
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to
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bring
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down
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the
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cost,
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and
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avoid
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the
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instability of
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upward
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flow
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caused
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by
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multiple
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pipes
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at
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the
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bottom.
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The
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major
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challenge
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in
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this
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new
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design
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is
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how
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to
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configure
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geometry
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of
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the
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water
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inlet
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at
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the
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bottom
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of
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the
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slopes
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to
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create
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flows
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as
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uniform
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as
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possible.
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Primitive Analysis
Intuitively,
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there
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are
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three
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basic
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situations
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of
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the
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water
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inlets.
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Water
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from
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both
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sides
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(collision
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region)
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Openings
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for
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water
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inlets
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on
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bothsides.
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Water
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flows
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from
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both
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sides,collide
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with
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each
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other
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and
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rise
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in
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the
...
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Water from one side (single flow)
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Opening for water inlets on one side. Water flows from one side, collide and rise along with the slope on the other side.
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Water from neither side (stagnation region)
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Opening on neither side. No flow from either side.
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Top view of influent water flows.
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Approach to the Problem
The flow field in the specified problem is completely complex 3D flow. However, in order to make the problem more doable we will start from simulating 2D cross-sections as analyzed above.