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Applied
- A ball that swings without spinning
- A big slow push
- A loss with no viscosity in it
- A pump with no engine
- A velocity nobody has
- Faster than the wind that drives it
- Half the jet speed takes everything
- Mixing is a pump
- One number picks the machine
- Stopping water costs more than moving it
- The bed that weighs itself
- The bubble that hammers
- The depth that costs least
- The drag that falls as it speeds up
- The fastest way is not the straight one
- The hole that halves the flow
- The instrument in the answer
- The most a disc can take
- The price of knowing the flow rate
- The radius that costs least
- The roughness a wall cannot feel
- The shock in a river
- The wake that has to spin
- What a jet cannot push sideways
- Where Darcy stops
- Work out of a change of swirl
- A number that is only the shape of the hole
- The section that decides the river
- A permeability that is only the geometry
- The angle a junction chooses
- The profile a meter cannot see
- The part of the closure a pipe cannot see
- The outlet is the inlet, a while ago
- A threshold that is also a duration
- The ball that never forgets its spin
- The group with no head in it
- What a turning frame keeps
- The stress that picks the aerodynamics
- A keel flies wherever the course puts it
- When a body tears the water
- A breeze the boat cannot use
- The duty that had no machine
- The better tunnel needs the bigger tank
- A tank that turns a hammer into a swing
- Twice the margin, on top of the hammer
- Matched at one speed and at no other
- Between hover and twice the hover inflow
- The specific speed a pump spends its life at
- The wall the suction puts in the curve
- A choke that belongs to two streams
- The nozzle that is best at one thing
Inviscid
- A body with no lift, and a moment anyway
- A wall made by reflection
- Ask for the pressure, and see what shape that is
- Bodies made out of nothing
- Flows add up
- From a circle to a wing
- The exact theory says nothing has any drag
- One function instead of two
- Pressure has no speed
- Fast means low pressure
- The theory that solves everything
- The force of getting going
- The number that does not depend on the tunnel
- Three dimensions are kinder
- Vortices move each other
- What survives being wound up
- What the far field remembers
- Where the reaction to a wing's lift is
- The flow with the least energy in it
- Where the unknown boundary is the known one
- The momentum with no value
- Inviscid does not mean irrotational
- The one rotational solution anybody can write down
- The vorticity nothing decides
- The exact theory, drawn by viscosity
- Three is the most that can be predicted
- Nothing turns a sharp corner
- The pressure that depends on the past
- The one thing that does not add up
- The body the outer flow actually sees
- The mirror that is a circle
- Drag in the theory that forbids it
- A sheet that cannot stay a sheet
- The shape a vortex keeps
- The part of the flow inside the body
- The swirl that holds a wave still
- The constant a hole leaves behind
- The drag that is made of waves
- What a point vortex is not
- The length the limit invents
- The corners that can be done with mirrors
- The mass a body has to borrow
- The lowest pressure is on the body
- How much more than the least
- The inside a flow does not decide
- The drift was the instrument
- A spiral is a legible record
- Reversible, and unusable
- Everything about the start, except one vector
- Nothing in the present picks the flow
- The theory with no memory in it
- Past three, an ellipse is a shear layer
Turbulence
- A guess with a constant in it
- A layer with a kink in it
- A millionth is enough
- A threshold with a closed form
- Every mode decays and it grows anyway
- Every wavelength at once
- Five numbers, one name
- How far a parcel gets
- The cascade that runs backwards
- The grid nobody can build
- The ladder that never closes
- The layer with no length in it
- The moment a spectrum cannot hold
- The number that stops the mixing
- The one exact result
- The solutions stop being chosen
- The street this site cannot draw
- The threshold the walls decide
- Three numbers left of a fluid
- Turbulent some of the time
- What averaging costs
- Where the energy goes
- A second length at the wall
- The range a real Reynolds number does not have
- The exponents that stop being thirds
- A flux that runs both ways
- Where the inverse cascade stops
- The constant that makes a variance negative
- Every unstable wave is inside one circle
- Sufficient, and not necessary
- Equal on average, and nothing else
- The scalar has its own cascade
- Three buffer layers, one friction
- The limit that is not the value
- What a code says to a wall
- A puff that does not know how old it is
- How far downwind a surface is remembered
- A dissipation that lags its production
- A closure with no memory at all
- A dissipation correlated across every scale
- A wake that keeps the drag and forgets the body
- What decay never forgets
- Hexagons remember how the heat was turned up
- The truncation that cannot carry three times the heat
- The number that is not a number
- The profile Rayleigh cleared and viscosity did not
- Universal, and one of five
- The constant that travels
- The fraction that is really four thirds
- A relation with no turbulence in it
- The decay inside the four-fifths law
Regimes
- A limit nothing reaches
- Counting what matters
- How far before the heat arrives
- How small is small enough
- One number decides which physics applies
- Slow enough to be steady
- The angle that does not care
- The balance that is its own error
- The model that cannot be matched
- The number that really is one
- The other layer, and the one number that separates them
- The pocket on top of the wing
- The Reynolds number, and the length in it
- The size a drop is allowed
- The tracer that is not one
- The wing the equation is really solving
- The world with no inertia
- Too fast for a profile
- Two slow things make a fast one
- What "of order one" is worth
- When air stops being incompressible
- Where a fluid stops being one
- Where a jet stops being a jet
- Where the parabola goes
- Whether the droplet turns
- Which speed goes in the number
- A solid, if it is not given time
- The frequency a wake chooses
- The number that cannot break a drop
- Long enough to make a wake
- The number that is an answer
- A transition that needs a second number
- A speed nobody imposed
- One group, three exponents
- An exponent dimensions cannot give
- One formula for both ends
- The three that never converge
- Where a pure number comes from
- Exact in the total, free in the profile
- The groups are not the only groups
- The drop that is not a tear
- Two forces, and only one of them remembers
- The state a machine was started into
- A wake told what to do
- Slip is a memory of one mean free path
- A particle is a low-pass filter
- Every memory number is one time over another
- The gusts that cancel along the chord
- The pulse that has to travel
- The pulse that grows as it leaves the heart
- The heat the eddies do not carry
Misconceptions
- Air must be pushed down, and the usual sum is wrong
- An angle, not a speed
- The story about air meeting up again
- Not half a venturi
- Nothing sucks
- The air a wing does not carry
- The bath does not know the hemisphere
- The bee that cannot fly
- The cushion that is not there
- The randomness that is not in the equations
- The siphon that does not need the air
- The theory that forbade flight
- What the airspeed indicator believes
- Where Bernoulli's equation applies
- An hour for every tenfold
- A right total from a wrong picture
- The effect that is real, and where it stops
- Four Bernoullis and one name
- The wing that is flat, and flies
- What a photograph of a flow shows
- A calculation with no memory in it
- The shutter is part of the answer
- The same statistics, and a different load
- The bath that was only ever a wait
- Where a liquid does pull
- A breaking strength that is the size of a flaw
- A cushion that changes its physics
- The borrowed mass the boundary decides
- The window every vector is averaged over
- One view is enough, and the axis pays for it
- The teapot effect is a tension, not a pressure
- The effect that explains nothing
- An instrument that takes a derivative
- The air that breaks a siphon nothing else can
- The margin friction lends a siphon
- A force forgets the datum, a stress cannot
- A roll that feeds itself
- A stall that is a place
- The cushion that is there after all
- The one place the atmosphere pushes
- The only theory simple enough to optimise
- The paint that measures the wrong field
- The siphon that does not break
- Weighing what is missing
- The face Newton left in shadow
- The venturi that stops listening downstream
- The drop a no-slip wall would never let spread
- The drag a wake keeps however it rolls up
- A choked throat buys time, not silence
- The spot a local theory cannot see
- Four cameras and a field they cannot see
Circulation
- A ring moves because it is bent
- A slot is not a nozzle
- A wake that closes on itself
- A wing that leaves the plane
- How much circulation is too much
- Lift out of a failure
- Lift with no wing at all
- Nothing but the edge
- The sharp edge decides
- The lift at the mean angle
- The lift beside a wing
- The lift curve, and why it is a straight line
- The lift that arrives late
- The loading nobody used
- The price of having ends
- The shake that is not resonance
- The span is the whole story
- The surface in the wake
- The vortex a wing leaves behind
- The wall that pushes back
- The walls are in the answer
- The wind a swept wing feels
- Two wings and it does not matter where
- What a flap does, and what it does not
- What actually holds a wing up
- Where lift starts
- Where the lift acts
- Where the wake ends up
- Which part of a wing stalls first
- A finite force from an infinite speed
- The half that carries nothing
- A disc that knows no blades
- The side that cannot keep up
- A row is not a set of aerofoils
- The condition that can be bought
- More lift than weight
- Where the line stops being a line
- The sweep a root does not have
- Two answers to one question
- The control that works backwards
- One formula, and it does not ask what the shape is
- The optimum that does not matter
- The speed where the damping is exactly zero
- Three numbers out of a camber line
- The lag that makes flutter possible
- Two lifts at one incidence
- A wake that says what made it
- A blade that flies through what it shed
- A row that meets the row before it
- The inflow that takes time to arrive
- Two rings leapfrog only if they start alike
- A lighter spar turns a box wing into a biplane
Compressible
- A shock that leans
- Drag with nothing to rub
- Energy instead of pressure
- One area, two answers
- One diaphragm, every wave
- The duct that works backwards
- The jump the equations allow
- The only law that forbids it
- The sound is what does not cancel
- The sound that only leaves
- The throat that stops listening
- The wall that cancels its own waves
- The wall that heats itself
- Turning the other way is free
- Two ways to choke
- What a shock costs
- What a signal travels at
- When the warning cannot arrive
- When the wedge is too blunt
- The other branch of the same curve
- When a shock cannot bounce
- The spin a shock leaves behind
- A shock that lies on the body
- The equation that changes type inside its own answer
- When gamma stops being a number
- The signature that forgets the shape
- A radius that gives the energy away
- The least drag a volume can have
- The discontinuity that has a thickness
- Every compression becomes a shock in the end
- A compression that costs nothing in the end
- Two numbers that do not change
- The jump does not ask what made it
- Slower than either of them
- A gas that has not finished being shocked
- A surface that remembers the diaphragm
- The sound now is the source then
- A gas that has not decided to react yet
- Two totals, one of which a shock cannot touch
- A duct that cannot be run backwards
- The thermometer that heats itself
- The jet a cone sprays sideways
- Friction moves the sonic point past the throat
- The skin that lags the flight
- A cone finishes its turn after the shock
- Three readings, and the one each answer leans on
- The gradient the heat never hears
- The boom that turns back before the ground
- The carpet an accelerating aeroplane folds
- The edge is a rumble, not a quieter bang
- A boom is aged in the thin air it starts in
Viscous
- An oscillation with somewhere to go
- How far before a duct forgets what was fed into it
- How much uphill a layer can take
- How thick is thin
- The two theories, side by side
- Nothing but the shape of the gap
- The cheapest way to stay up
- The cost of going turbulent
- The eddies nobody stirs
- The gradient that does both
- The layer that stops at a depth
- The layer that stops growing
- Everything happens in a layer you cannot see
- The two drags a wing pays
- The wall that shakes
- What a jet keeps, and what it collects
- What viscosity cannot take away
- When the flow lets go
- Where the straight line stops
- The price of a gradient
- Where the heat of a drag is made
- The cheapest shape the walls allow
- A force without the flow that makes it
- The last of the oil
- The film that heats itself
- What a plate takes with it
- A viscosity that depends on the question
- A viscosity made of particles
- The surface that moves with the flow
- The third thickness
- The energy a vortex cannot have
- A swimmer that cannot go backwards
- The viscosity nobody uses
- What a fluid takes out of a swing
- The flow with no solution
- The singularity a layer makes for itself
- The core that does not move
- The gap that carries the most
- Exactly similar, and one number short
- Four profiles, one drag
- The stress a pipe knows
- The drag that integrates a whole history
- The wall the fluid is listening to
- The fluid that has not finished its last deformation
- A layer that is an integral of everything upstream
- How long a fluid takes to forget it was not rotating
- A duct that forgets everything but one number
- The solution that keeps its nonlinear term
- One channel, one flux, two flows
- Why the list is this long
Kinematics
- A wall that is not quite there
- Circulation is vorticity, added up
- How many things a flow must be told
- Mass has nowhere to go
- No randomness, and it mixes anyway
- Spin is not the same as going round
- Streamlines are not the paths particles take
- The count a pattern cannot break
- The drift in a wave that has none
- The mean is not the flow
- The number on a streamline is a flow rate
- The spin that feeds itself
- What a flow is
- What a parcel does in the first instant
- Where vorticity comes from
- The picture belongs to whoever is watching
- Every flow is two flows
- A rate of change that will not hold still
- Longer, with nothing pulling it
- Where a vortex stops
- Incompressible is not a property of the fluid
- The one number that runs out at three dimensions
- A wave nothing in it travels with
- Steady, three-dimensional, and mixing anyway
- The knot a flow cannot untie
- The stretching rate that is not one number
- The area that must not move
- The drift a closed box will not allow
- The mesh that makes its own mass
- Two averages of one flow
- Steady does not mean nothing is happening
- Two strainings, and the order they came in
- A drift made of two things that average to zero
- A boundary that only exists over a window
- What a mean profile cannot tell anybody
- How long the fluid has been in there
- A scalar is a record of where its fluid was
- Two kinds is a plane flow's privilege
- The curve that measures a gradient
- A wall puts in exactly its own speed
- Twice as slippery along as across
- The vorticity a clean surface cannot refuse
- The count computed on a body
- The line the dye actually draws
- The sign a stagnation point carries in space
- The drift a rotating planet takes back
- The column the chord rule cannot settle
- A wave on the wall is a pump
- The drift that turns a current into rolls
- The floor that gives the drift back
- The pump that is better the more it squeezes