fix typos
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@@ -22,9 +22,9 @@ These are ideas you need to know about to know what's going on, I guess?
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## Control Volumes
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A control volume is a volume with an imaginary boundry to make it easier to analyze the flow of a
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A control volume is a volume with an imaginary boundary to make it easier to analyse the flow of a
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fluid.
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The boundry is drawn where the properties and conditions of the fluid is known, or where an
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The boundary is drawn where the properties and conditions of the fluid is known, or where an
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approximation can be made.
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Properties which may be know include:
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@@ -33,7 +33,7 @@ Properties which may be know include:
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- Temperature
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- Viscosity
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The region in the control volume is analyed in terms of enery and mass flows entering and leaving
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The region in the control volume is analysed in terms of energy and mass flows entering and leaving
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the control volumes.
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You don't have to understand what's going on inside the control volume.
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@@ -50,7 +50,7 @@ momentum or the air passing through the engine.
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The control volume is drawn far enough in front of the engine that the air velocity entering can
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be assumed to be at atmospheric pressurce and its velocity negligible.
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be assumed to be at atmospheric pressure and its velocity negligible.
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At the exit of the engine the boundary is drawn close where the velocity is known and the air
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pressure atmospheric.
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@@ -97,7 +97,7 @@ with respect to time, like the opposite of steady flow.
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## One Dimensional Flow
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In one dimensional (1D) flow it is assumed that all properties are uniform over any plane
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perpedenciular to the direction of flow (e.g. all points along the cross section of a pipe have
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perpendicular to the direction of flow (e.g. all points along the cross section of a pipe have
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identical properties).
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This means properties can only flow in one direction---usually the direction of flow.
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@@ -132,7 +132,7 @@ Same reasoning with if they are not parallel.
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### Pathlines
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A pathline shows the route taken by a single particle during a given time interval.
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It is equivalent to a high exposure photograph which traces the moevement of the particle marked.
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It is equivalent to a high exposure photograph which traces the movement of the particle marked.
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You could track pathlines with a drop of injected dye or inserting a buoyant solid particle which
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has the same density as the solid.
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@@ -222,15 +222,15 @@ Between fully laminar and fully turbulent flows is a transition region.
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### Development of the Reynolds Number
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In laminar flow the most influentialfactor is the magnitude of the viscous forces:
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In laminar flow the most influential factor is the magnitude of the viscous forces:
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$$viscous\, forces \propto \mu\frac v l l^2 = \mu vl$$
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where $v$ is a characteristic velocit and $l$ is a characteristic length.
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where $v$ is a characteristic velocity and $l$ is a characteristic length.
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In turbulent flow viscous effects are not significant but inertia effects (mixing, momentum
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exchange, acceleration of fluid mass) are.
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Interial forces can be represented by $F = ma$
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Inertial forces can be represented by $F = ma$
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\begin{align*}
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m &\propto \rho l^3 \\
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@@ -240,7 +240,7 @@ a &= \frac{dv}{dt} \\
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&\therefore \text{Interial forces} \propto \rho l^2\frac{v^2} l = \rho l^2v^2
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\end{align*}
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The ratio of internalforces to viscous forces is called the Reynolds number and is abbreviated to
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The ratio of internal forces to viscous forces is called the Reynolds number and is abbreviated to
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Re:
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$$\Rey = \frac{\text{interial forces}}{\text{viscous forces}} = \frac {\rho l^2v^2}{\mu vl} = \frac {\rho vl} \mu$$
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@@ -248,12 +248,12 @@ $$\Rey = \frac{\text{interial forces}}{\text{viscous forces}} = \frac {\rho l^2v
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where $\rho$ and $\mu$ are fluid properties and $v$ and $l$ are characteristic velocity and length.
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- During laminar flow, $\Rey$ is small as viscous forces dominate.
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- During turbulent flow, $\Rey$ is large as intertial forces dominate.
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- During turbulent flow, $\Rey$ is large as inertial forces dominate.
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\textRey is a non dimensional group.
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It has no units because the units cancel out.
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Non dimensional groups are very important in fluid mechancics and need to be considered when scaling
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Non dimensional groups are very important in fluid mechanics and need to be considered when scaling
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experiments.
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If \textRey is the same in two different pipes, the flow will be the same regardless of actual
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@@ -285,7 +285,7 @@ $$\frac 1 \rho \frac{\delta p}{\delta s} + g\frac{\delta z}{\delta s} + v\frac{\
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## Assumptions / Conditions
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The Euler euqation applies where the following can be assumed:
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The Euler equation applies where the following can be assumed:
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- Steady flow
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- The fluid is inviscid
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@@ -350,7 +350,7 @@ $$\frac p {\rho g} + z + \frac{v^2}{2g} = H_T$$
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where $H_T$ is constant and:
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- $\frac{p}{\rho g}$ --- static/pressure haed
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- $\frac{p}{\rho g}$ --- static/pressure head
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- $z$ --- elevation head
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- $\frac{v_2}{2g}$ --- dynamic/velocity head
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- $H_T$ --- total head
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@@ -399,9 +399,9 @@ SFEE is a more general equation that can be applied to **any fluid** and also is
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**heat energy** into account.
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This is useful in applications such as a fan heater, jet engines, ICEs, and steam turbines.
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The equation deals with 3 types of energy tranfer:
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The equation deals with 3 types of energy transfer:
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1. Thermal energy transfer (e.g. heat tranfer from central heating to a room)
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1. Thermal energy transfer (e.g. heat transfer from central heating to a room)
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2. Work energy transfer (e.g. shaft from car engine that turns wheels)
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3. Energy transfer in fluid flows (e.g. heat energy in a flow, potential energy in a flow, kinetic
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energy in a flow)
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@@ -450,7 +450,7 @@ $$\delta E = \delta E_2 - \delta E_1 = \delta m(e_2 - e_1)$$
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#### The Work Term
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The work term, $\delta W$, is mae up of shaft work **and the work necessary to deform the system**
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The work term, $\delta W$, is made up of shaft work **and the work necessary to deform the system**
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(by adding $\delta m_1$ at the inlet and removing $\delta m_2$ at the outlet):
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$$\delta W = \delta W_s + \text{net flow work}$$
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@@ -583,7 +583,8 @@ However be aware that in North America the equation is:
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$$H_f = f \frac{L}{D} \frac{v^2}{2g}$$
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Their $f$ (the Darcy Friction Factor) is four times our $f$ (Fanning Friction Factor).
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In mainland Europe, they use $\lambda = 4f_{Fanning}$, which is probably the least confusing version to use.
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In mainland Europe, they use $\lambda = 4f_{Fanning}$, which is probably the least confusing version
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to use.
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### Finding $f$
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