Open Channel Flow Exam 1

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The E-y diagram gives - depths

alternate

any pair of depths that correspond to the same specific energy for a given discharge are referred to as - depths

alternate

the depths upstream and downstream of a sluice gate on a horizontal bed are - depths

alternate

the E-y diagram is useful for seeing -

alternate depths, effect of choke when the gate depth decreases to less than the alternate depth to the initial upstream depth, the energy loss in a hydraulic jump

you - energy in a hydraulic jump

lose

for steady unform flow, use - to obtain normal depth

mannings equation

for a fixed specific energy, specific discharge is - at critical conditions

maximized

if y(0) > y(crit), the channel is -

mild

the bernoulli equation is conserving -

momentum

the saint venant equation is conserving -

momentum

the more supercritical the flow upstream of the jump, the (more/less) subcritical will be the flow downstream of the jump

more

during a vertical drop or expansion, can the system be choked?

no

what is uniform flow

no change in x

what is steady flow

no change with time

- depth is observed under uniform flow conditions

normal

in a stepped channel, the water surface and bed are - if Fr < 1

out of phase (WSE decreases when bed height increases)

simplified version of the reynold's transport theorm

rate of change of F within control volume + sum of the flow rate of F passing through the control surface

for steady uniform flow, driving gravitational force equals -

resisting frictional force

for the case of steep to mild conditions, if M(1) > M(2), the HJ will occur in the - reach

second

depths just downstream and upstream of a hydraulic jump are - depths

sequent

The M-y diagram gives - depths

sequent or conjugate

two methods to solving quantitatively gradually varied flow

simple finite difference, HEC-RAS

what is hydrologic routing

solves continuity equation (no force)

what is hydraulic routing

solves momentum and continuity (considers force)

bernoullis equation minus pressure head

specific energy

the bernoulli equation assumes -

steady and frictionless

what are the conditions of GVF

steady, nonuniform, friction

what are the three ways you can classify flow

steady/uniformness, laminar vs turbulent, flow criticality

if y(0) < y(crit), the channel is -

steep

natural examples of open channel

stream, overland flow, estuaries/coastal

- flows occurs when the flow depth is greater than y(crit)

subcritical

If Fr < 1, the flow is -

subcritical

On an E-y diagram, values above y(crit) are -

subcritical

- flows occurs when the flow depth is less than y(crit)

supercritical

If Fr > 1, the flow is -

supercritical

On an E-y diagram, values below y(crit) are -

supercritical

the energy possessed by a flow of water

total head

when does a hydraulic jump happen

transition from super to sub critical flow

when does a hydraulic jump occur

transitioning from super to sub critical

almost all natural flows are (laminar/turbulent)

turbulent

- flow does not change in depth along the direction of flow in an open channel

uniform

what type of flow does not exist in nature

unsteady uniform flow

chezys equation uses the assertion that shear stress is directly proportional to -

velocity head

what is the reynold's transport theorem

way to convert from a system definition to a control volume definition

when flowing from a steep to mild reach, what does the WSE profile look like if y(0, b, conj) > y(0, a)

y(0, a) until transition point, M3 until y(0, b, conj), HJ to y(0, b)

when flowing from a steep to mild reach, what does the WSE profile look like if y(0, b, conj) < y(0, a)

y(0, a), HJ until y(0, a, conj), S1 until transition point @ y(0,b)

when flowing from negative mild reach to a negative less mild reach, what does the WSE profile look like

y01, M2 to transition line, y02

when flowing from negative mild slope to a negative steep slope, what does the WSE profile look like

y01, M2, pass through critical when transitions from mild to steep, S2, y02

what is the eularian frame of reference

you stand still

a hydraulic choke occurs when -

E < E(crit)

case of slowly changing (with distance) non-uniform flow

GVF

for the case of steep to mild conditions, the hydraulic jump will occur in the reach that -

has the least momentum

What does "open channel flow" mean

- open = open to the atmosphere channel flow = boundaries on 3 or more sides that contain the flow

for the case of steep to mild conditions, if y(0, up) > y(0, down, seq), the HJ will occur in reach -

1 (upstream)

at critical conditions in a rectangular channel for a given specific discharge, the energy is at a minimum value and is equal to - times the critical depth

1.5

for the case of steep to mild conditions, if y(0, up) < y(0, down, seq), the HJ will occur in reach -

2 (downstream)

energy grade lines =

E + z(b)

just upstream of a sluice gate, what reach takes the WSE from normal to alternate depth of the gate height

M1 or S1

just downstream of a sluice gate, what reach takes the WSE from gate height to the sequent depth of normal

M3 or S3

given Q and geometry of channel, we want to find

Q and A or v and y

if energy is decreasing in the direction of the flow, what does that mean

S(0) > S(f)

if all energy loss in a system is from friction, then -

S(e) = S(f), cons of momentum = cons of energy

Basic finite difference is based on -

Taylor Series

what is muskinghum-cunge

blending of hydraulic and hydrologic routing

what is the driving forces of open channel flow

body force due to acceleration of gravity

GVF requires -

boundary conditions

unsteady flow requires -

boundary conditions and initial conditions

built examples of open channel flow

canal, swale, stormwater, irrigation channel

what is nonuniform flow

change in x

what is unsteady flow

change with time

chezy and manning formulas relate velocity to -

channel characteristics

the M-y diagram is useful for seeing -

conjugate depths, loss in momentum at the sluice gate

conservation of volume is called the - equation

continuity

If Fr = 1, the flow is -

critical

if y(0) = y(crit), the channel is -

critical

the depth that corresponds to the minimum specific energy for a given q

critical depth

with a kinematic wave, there is no -. just pure -.

deformation, translation

information can propagate (upstream/downstream) in a supercritical flow

downstream

what causes different GVF profiles

downstream WSE controls, slope change, obstructions/chokes

information can propagate (upstream/downstream) in a subcritical flow

downstream and upstream

for uniform flow, - is constant

energy

in a series, - is constant

flow (Q)

if the approaching flow to a choked channel is subcritical, - will occur

flow will back up

what is the lagrangian frame of reference

follows the particle

the water surface elevation of a choked systems depends on the -

froude state of the approaching flow

what is the governing equation for unsteady flow

full saint venant

types of nonuniform flow

gradually varied flow and rapidly varied flow

for steady uniform flow, - included

gravity and friction

On an E-y diagram, E must be - than E(min) for a solution to exist

greater than

in parallel, - is constant

headloss

if the approaching flow to a choked channel is supercritical, - will occur

hydraulic jump

two types of flood wave routing

hydrologic and hydraulic routing

in a stepped channel, the water surface and bed are - if Fr > 1

in phase (WSE increases when bed height increases)

On a E-y diagram, as q increases, E will - if y stays the same

increases

what is the froude number a ration of

inertial force over gravitational force OR velocity over velocity

If Fr < 1, the flow is/isnt impact by downstream

is

If Fr > 1, the flow is/isnt impact by downstream

isn't

types of hydraulic routing waves

kinematic, diffusion, dynamic

what are the two frames of reference

lagrangian and eularian


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