# The Turbulent History of Fluid Mechanics

Naomi Tsafnat

May 17, 1999.

It all started with Archimedes, way back in BC,

Who was faced with an interesting problem, you see…

The king came to me, and this story he told:

I am not sure if my crown is pure gold.

You are a wise man, or so it is said,

Tell me: is it real, or is it just lead?

I paced and I thought, and I scratched my head,

But the answer eluded me, to my dread.

I sat in my bath, and pondered and tried,

And then … Eureka! Eureka! I found it! I cried.

As I sat in my tub and the water was splashing,

I knew suddenly that a force had been acting.

On me in the tub, its proportional, see,

To the water that was where now there is me.

Of course, Archimedes caused quite a sensation

But not because of his great revelation;

As he was running through the streets of Syracuse

He didnt notice he was wearing only his shoes.

The great Leonardo oh what a fellow

No, not diCaprio, DaVinci I tell you!

He did more than just paint the lovely Mona,

He also studied fluid transport phenomena.

Then came Pascal, who clarified with agility,

Basic concepts of pressure transmissibility.

Everyone knows how a barometer looks,

But he figured out just how it works.

How can we talk about great scientists,

Without mentioning one of the best:

Sir Isaac Newton, the genius of mathematics,

Also contributed to fluid mechanics.

One thing he found, and its easy as pie,

Is that shear stress, ?~D equals μ dv/dy.

His other work, though, was not as successful;

His studies on drag were not all that useful.

He thought he knew how fast sound is sent,

But he was way off, by about twenty percent.

And then there was Pitot, with his wonderful tubes,

Which measure how fast an airplane moves.

Poiseuille, dAlembert, Lagrange and Venturi

Through his throats fluid pass in a hurry.

Here is another hero of fluid mechanics,

In fact, he invented the word hydrodynamics.

It would take a book to tell you about him fully,

But here is the short tale of Daniel Bernoulli:

Everyone thinks is just one Bernoulli

It is not so! There are many of us, truly.

My family is big, many scientists in this house,

With father Johan, nephew Jacob and brother Nicolaus.

But the famous principle is mine, you know,

It tells of the relationship of fluid flow,

To pressure, velocity, and density too.

I also invented the manometer - out of the blue!

Yes, Bernoulli did much for fluids, you bet!

He even proposed the use of a jet.

There were others too, all wonderful folks,

Like Lagrange, Laplace, Navier and Stokes.

Here is another well-known name,

A mathematician and scientist of great fame:

He is Leonard Euler, Im sure you all know,

His equations are basis for inviscid flow.

He did more than introduce the symbols ?~@, I, e,

He also derived the equation of continuity.

And with much thought and keen derivation,

He published the famous momentum equation.

Those wonderful equations and diagrams you see?

They are all thanks to Moody, Weisbach and Darcy.

Then there was Mach, and the road that he paves,

After studying the shocking field of shock waves.

Rayleigh studied wave motion, and jet instability,

How bubbles collapse, and dynamic similarity.

He was also the first to correctly explain.

Why the sky is blue except when it rains.

Osborne Reynolds, whose number we know,

Found out all about turbulent flow.

He also examined with much persistence,

Cavitation, viscous flow, and pipe resistance.

In the discovery of the boundary layer

Prandtl was the major player.

Its no wonder that all the scientists say,

He’s the father of Modern Fluid Mechanics, hooray!

It is because of Prandtl that today we all can

Describe the lift and drag of wings of finite span.

If it werent for him, then the brothers Wright

Would probably never have taken flight.

And so we come to the end of this story,

But its not the end of the tales of glory!

The list goes on, and it will grow too

Maybe the next pioneer will be you?