Flat Tire; Possible Causes?

[RotorAndWing]

A friends car had a flat tire today. Can anyone discuss the possible cause?

 

[Everskyward]

Not following the "ops specs".

 

[Fearless Tower]

Coleslaw. Definitely coleslaw.

 

[flyingron]

Wrong number of plies.

 

[SixPapaCharlie]

or and possibly

 

[Howard Wilson]

Flatulence?

 

[Terry L in KY]

Was it flat all the way around? Or, just the bottom?

 

[Sleepingsquirrel]

HUSBAND failed to check the tire pressure for her.

 

[Scotty78]

Low blinker fluid level.

 

[Mason]

Lack of Air.

Or, global warming.

 

[wsuffa]

failure of the cannibulator valve.

 

[Clark1961]

OP's lack of intelligence

 

[N801BH]

It is Bush's fault....

 

[N3368K]

https://upload.wikimedia.org/math/4/2/8/428dd259d71ea73de82f67e2feb48bcf.png


Jim R
Collierville, TN

N7155H--1946 Piper J-3 Cub
N3368K--1946 Globe GC-1B Swift
N4WJ--1994 Van's RV-4

 

[Jim Logajan]

A friends car had a flat tire today. Can anyone discuss the possible cause?

It was thirsty?

 

[Bob Noel]

Brady did it!!!!

 

[Fearless Tower]

Brady did it!!!!

Ah, yes. That's what he's missing: Tell your friend to destroy his cell phone.

 

[frfly172]

Didn't follow the check list completely.

 

[Checkout_my_Six]

lack of breath.....killed em.

 

[weirdjim]

Failure to file flight plan. Always the problem.4


Jim

 

[SteveCanyon]

No flight plan

 

[jordane93]

Failure to file flight plan. Always the problem.4


Jim

Yea or not talking to tower

 

[DesertNomad]

The car was loaded with 17 tons of bowling balls.

 

[Checkout_my_Six]

deflation.....

 

[Jimmy cooper]

Even more exciting than this is that my car warning light came on saying that I need air in my tires! I promptly took care of it.

 

[Tom-D]

Haven't you guys learned when you are being trolled?

 

[BigBadLou]

What makes you think we didn't notice?
I think all the answers here speak for themselves.

 

[Zeldman]

Ok class first we need to look at why the tire must have pressure to accomplish the task needed. Please pay attention as I only have time to go through this once:

explicitly a PDE:

and adapted it to the case of a plasma, leading to the systems of equations shown below.[5]


Instead of collision-based kinetic description for interaction of charged particles in plasma, Vlasov utilizes a self-consistent collective field created by the charged plasma particles. Such a description uses distribution functions

and

for electrons and (positive) plasma ions. The distribution function

for species α describes the number of particles of the species α having approximately the momentum

near the position

at time t. Instead of the Boltzmann equation, the following system of equations was proposed for description of charged components of plasma (electrons and positive ions):

Here e is the electron charge, c is the speed of light, mi is the mass of the ion,

and

represent collective self-consistent electromagnetic field created in the point

at time moment t by all plasma particles. The essential difference of this system of equations from equations for particles in an external electromagnetic field is that the self-consistent electromagnetic field depends in a complex way on the distribution functions of electrons and ions

and

.

and Poisson's equation for self-consistent electric field:

Here qα is the particle's electric charge, mα is the particle's mass,

is the self-consistent electric field,

the self-consistent electric potential and ρ is the electric charge density.
Vlasov–Poisson equations are used to describe various phenomena in plasma, in particular Landau damping and the distributions in a double layer plasma, where they are necessarily strongly non-Maxwellian, and therefore inaccessible to fluid models.

In fluid descriptions of plasmas (see plasma modeling and magnetohydrodynamics (MHD)) one does not consider the velocity distribution. This is achieved by replacing

with plasma moments such as number density n, flow velocity u and pressure p.[6] They are named plasma moments because the n-th moment of

can be found by integrating

over velocity. These variables are only functions of position and time, which means that some information is lost. In multifluid theory, the different particle species are treated as different fluids with different pressures, densities and flow velocities. The equations governing the plasma moments are called the moment or fluid equations.
Below the two most used moment equations are presented (in SI units). Deriving the moment equations from the Vlasov equation requires no assumptions about the distribution function.
The continuity equation describes how the density changes with time. It can be found by integration of the Vlasov equation over the entire velocity space.

After some calculations, one ends up with

The number density n, and the momentum density nu, are zeroth and first order moments:

The rate of change of momentum of a particle is given by the Lorentz equation:

By using this equation and the Vlasov Equation, the momentum equation for each fluid becomes

, where p is the pressure tensor. The material derivative is

The pressure tensor is defined as the particle mass times the covariance matrix of the velocity:

As for ideal MHD, the plasma can be considered as tied to the magnetic field lines when certain conditions are fulfilled. One often says that the magnetic field lines are frozen into the plasma. The frozen-in conditions can be derived from Vlasov equation.
We introduce the scales T, L and V for time, distance and speed respectively. They represent magnitudes of the different parameters which give large changes in

. By large we mean that

We then write

Vlasov equation can now be written

So far no approximations have been done. To be able to proceed we set

, where

is the gyro frequency and R is the gyroradius. By dividing by ωg, we get

If

and

, the two first terms will be much less than

since

and

due to the definitions of T, L and V above. Since the last term is of the order of

, we can neglect the two first terms and write

This equation can be decomposed into a field aligned and a perpendicular part:

The next step is to write

, where

It will soon be clear why this is done. With this substitution, we get

If the parallel electric field is small,

This equation means that the distribution is gyrotropic.[7] The mean velocity of a gyrotropic distribution is zero. Hence,

is identical with the mean velocity, u, and we have

To summarize, the gyro period and the gyro radius must be much smaller than the typical times and lengths which give large changes in the distribution function. The gyro radius is often estimated by replacing V with the thermal velocity or the Alfvén velocity. In the latter case R is often called the inertial length. The frozen-in conditions must be evaluated for each particle species separately. Because electrons have much smaller gyro period and gyro radius than ions, the frozen-in conditions will more often be satisfied.

Ok, now it should be clear to everyone.

There will be a test tomorrow....

 

[N801BH]

Can you please expand on that concept a bit more....

 

[Clark1961]

Zeldman as usual, overthinks the problem and comes up with useless commentary while actually not contributing to a practical or legal solution. The proposed solution is obviously incorrect as the sign is reversed in equation 12 and there are undefined terms in equation 25 a). Even the boundary conditions are suspect since they aren't graphically presented.

This paper is not even ready for peer review, much less publication. Recommend a major re-wright and re-submittal.

Private note to chief editor: don't send crap like this to me again, if it is an obvious waist of time just down it on the spot.

 

[gitmo234]

Haven't you guys learned when you are being trolled?

what would you do to diagnose someone trolling?

 

[Clark1961]

what would you do to diagnose someone trolling?

I'd look for a boat...

 

[Tom-D]

what would you do to diagnose someone trolling?

I wouldn't.

Because it is too easy/fun to yank your chain.

 

[Checkout_my_Six]

was it a rubber tire....or synthetic?

 

[geneseib]

A friends car had a flat tire today. Can anyone discuss the possible cause?

No air.

 

[Tom-D]

A friends car had a flat tire today. Can anyone discuss the possible cause?

Like some pilots I know, the friend was too cheap to properly maintain their car.

 

[NoHeat]

A friends car had a flat tire today. Can anyone discuss the possible cause?

Your friend misplaced an apostrophe.

That was the cause. They are kind of sharp and pointy, you know, so it is bad to leave them in the wrong place.

 

[F01LA]

There is a simple cause, but I don't have enough room to fit it between the margins on this post.

 

[JOhnH]

That was straight out of my Grandmother's recipe book. I believe it was for her version of kimchi cooked in a pressure cooker.

Ok class first we need to look at why the tire must have pressure to accomplish the task needed. Please pay attention as I only have time to go through this once:

explicitly a PDE:

and adapted it to the case of a plasma, leading to the systems of equations shown below.[5]


Instead of collision-based kinetic description for interaction of charged particles in plasma, Vlasov utilizes a self-consistent collective field created by the charged plasma particles. Such a description uses distribution functions

and

for electrons and (positive) plasma ions. The distribution function

for species α describes the number of particles of the species α having approximately the momentum

near the position

at time t. Instead of the Boltzmann equation, the following system of equations was proposed for description of charged components of plasma (electrons and positive ions):

Here e is the electron charge, c is the speed of light, mi is the mass of the ion,

and

represent collective self-consistent electromagnetic field created in the point

at time moment t by all plasma particles. The essential difference of this system of equations from equations for particles in an external electromagnetic field is that the self-consistent electromagnetic field depends in a complex way on the distribution functions of electrons and ions

and

.

and Poisson's equation for self-consistent electric field:

Here qα is the particle's electric charge, mα is the particle's mass,

is the self-consistent electric field,

the self-consistent electric potential and ρ is the electric charge density.
Vlasov–Poisson equations are used to describe various phenomena in plasma, in particular Landau damping and the distributions in a double layer plasma, where they are necessarily strongly non-Maxwellian, and therefore inaccessible to fluid models.

In fluid descriptions of plasmas (see plasma modeling and magnetohydrodynamics (MHD)) one does not consider the velocity distribution. This is achieved by replacing

with plasma moments such as number density n, flow velocity u and pressure p.[6] They are named plasma moments because the n-th moment of

can be found by integrating

over velocity. These variables are only functions of position and time, which means that some information is lost. In multifluid theory, the different particle species are treated as different fluids with different pressures, densities and flow velocities. The equations governing the plasma moments are called the moment or fluid equations.
Below the two most used moment equations are presented (in SI units). Deriving the moment equations from the Vlasov equation requires no assumptions about the distribution function.
The continuity equation describes how the density changes with time. It can be found by integration of the Vlasov equation over the entire velocity space.

After some calculations, one ends up with

The number density n, and the momentum density nu, are zeroth and first order moments:

The rate of change of momentum of a particle is given by the Lorentz equation:

By using this equation and the Vlasov Equation, the momentum equation for each fluid becomes

, where p is the pressure tensor. The material derivative is

The pressure tensor is defined as the particle mass times the covariance matrix of the velocity:

As for ideal MHD, the plasma can be considered as tied to the magnetic field lines when certain conditions are fulfilled. One often says that the magnetic field lines are frozen into the plasma. The frozen-in conditions can be derived from Vlasov equation.
We introduce the scales T, L and V for time, distance and speed respectively. They represent magnitudes of the different parameters which give large changes in

. By large we mean that

We then write

Vlasov equation can now be written

So far no approximations have been done. To be able to proceed we set

, where

is the gyro frequency and R is the gyroradius. By dividing by ωg, we get

If

and

, the two first terms will be much less than

since

and

due to the definitions of T, L and V above. Since the last term is of the order of

, we can neglect the two first terms and write

This equation can be decomposed into a field aligned and a perpendicular part:

The next step is to write

, where

It will soon be clear why this is done. With this substitution, we get

If the parallel electric field is small,

This equation means that the distribution is gyrotropic.[7] The mean velocity of a gyrotropic distribution is zero. Hence,

is identical with the mean velocity, u, and we have

To summarize, the gyro period and the gyro radius must be much smaller than the typical times and lengths which give large changes in the distribution function. The gyro radius is often estimated by replacing V with the thermal velocity or the Alfvén velocity. In the latter case R is often called the inertial length. The frozen-in conditions must be evaluated for each particle species separately. Because electrons have much smaller gyro period and gyro radius than ions, the frozen-in conditions will more often be satisfied.

Ok, now it should be clear to everyone.

There will be a test tomorrow....

 

[JOhnH]

A friends car had a flat tire today. Can anyone discuss the possible cause?

Maybe it was a new female tire that hadn't had a chance to develop yet. If time doesn't cure it, stuff it with paper towels, or for a more permanent fix, try silicone.