One Hundred Thousand Unsolved Mysteries

John continued: "Your father's algorithm is indeed the most outstanding work of mankind, but it is far from powerful enough. Therefore, we have no way to make the nuclear fusion device smaller, and each reactor is like a mountain. , is simply too rough."

Zhang Yuan looked at these turbulences, some were bright, some were dim, and some were spinning, and fell into deep thought.

Regardless of whether he is convinced or not, John's complaint is indeed correct.

There was a little ambition in his heart, which took root and sprouted like a seed.

"The question that my father once did, maybe... I can do it too?!"

The problem of turbulence, the last big mountain in classical physics. About 400 years ago, the Navier-Stokes equation, also known as the NS equation, had theoretically described the physics of fluids. This equation is generally difficult to find an exact solution, so scientists usually use some simplified theoretical models or resort to numerical simulation methods to predict the movement of fluids.

But using a simplified model to simulate plasma turbulence is too imprecise. If these plasmas are not well confined, they can wreak havoc on a fusion engine.

The vigorous development of informatics has made the problem of turbulence loose, but it is only a little loose. It can be simulated more accurately, but it cannot deeply understand its true nature.

John sighed: "We may never find a mathematically accurate solution to the turbulence problem. Perhaps the complete accuracy is hidden in a more microscopic probability superposition state. With our ability, we don't know it at all."

John Wilson is a typical representative of the pessimist.

He believes that the upper limit of human technology is likely to be what it is now, and with human IQ, it can only turn around in such a small circle.

Although there are still some minutiae things to be polished, it is impossible to truly achieve a qualitative change.

Therefore, this group of pessimistic scientists want to board the spacecraft and want to see the world three thousand years later.

This statement is not unreasonable. A turbulence problem has not been completely solved after four hundred years.

In cutting-edge physics, except for condensed matter, which still maintains vigorous vitality, the others have gradually declined. High-energy physics is plagued by "energy level deserts". Other disciplines, such as chemistry and semiconductors, use some approximate theories. The most important thing is that these approximate theories can indeed solve some problems.

As for mathematics, it is also slowly going downhill.

Riemann's conjecture, it has been standing for 400 years; Goldbach's conjecture, it has been 600 years.

The "Mathematical Unification" project is still only a framework, and it is still tens of billions of light years away from completion.

The New Civilization School believes that the current 23rd century, plus the 24th and 25th centuries, is likely to be the last golden age of mankind. Next, the overall intelligence of human beings cannot continue to develop.

Once the development of science and technology stagnates, human civilization is likely to experience the phenomenon of historical reincarnation like the ancient Xia Kingdom. To use academic terms, it is difficult to make great historical progress by falling into the "trap of mediocrity".

Zhang Yuan actually agrees with some of the views of the New Civilization School, but he is neither pessimistic nor optimistic about this issue.

He actually doesn't believe that human beings will be stupid enough to fall into foreseeable traps, and it's hard to imagine what the future world will be like, maybe there will be some technologies that transform intelligence.

In addition, the direction he is engaged in is more inclined to engineering and technology. There is still a big difference between technology and science, and there is indeed a lot of room for improvement in the application of human technology.

"Zhang, you are too optimistic."

John shrugged his shoulders and said helplessly: "In history, there are many phenomena, such as Latin Americanization, the income trap of middle-level countries, etc. Even if some countries know it clearly, they still cannot overcome it, because many things in a country, It's not something the leaders can do when they are aware of it. It has to rely on the strength of the whole."

"But the collective power of mankind is not as powerful as you imagine."

"Yeah, you're right." Zhang Yuan said, "But we have to be optimistic, don't we? Pessimism can't solve any problems."

After bidding farewell to this sentimental brother John, Zhang Yuan returned to his laboratory seat and continued to read the literature.

Accidentally turned to a book.

"One Hundred Thousand Unsolved Mysteries"...

From astronomy to geography, from mathematics to physics, there are too many difficult problems that cannot be solved. For example, the "3x+1" conjecture, the happy ending problem, the Gaussian circle problem, the Erdos-Graham ternary problem...any one, the difficulty is comparable to Li's guess.

For some reason, looking at the countless problems, Zhang Yuan always had a slight sense of irritation in his heart.

Perhaps, as a member of scientific research workers, I am not able to completely penetrate the natural instinct and anger.

Zhang Yuan squeezed his fist secretly.

At this moment, he finally made up his mind to solve a world-renowned problem.

It doesn't matter whether you gain or lose, just follow your own heart.

"Turbulence problem!"

"Try it!"

It takes a lot of courage.

It is likely that a lot of time has been spent, nothing can be achieved, and the sunk cost is huge. Only a young man like him can move forward bravely with his passion.

After making up his mind, Zhang Yuan let out a long breath and slowly settled down.

From a purely mathematical point of view, there is basically not much possibility.

Zhang Yuan doesn't think that with his current strength, he can write more accurate and effective equations than NS equations.

"Perhaps, some informatics methods can be created to solve this problem."

The first method is the famous "spectral method of wavelet transform" used by my father, and it is also the best algorithm in engineering applications at present. It successfully solves the problem of turbulent flow simulation in which the flow inside the engine is multi-scale in both time and space.

In essence, it refers to the transmission process of signals in neurons to describe the bursting mechanism of turbulent flow in pipelines.

The second method is the method of direct numerical solution.

Isotropic turbulent flow in a three-dimensional periodic cube is simulated by solving the "NS equations" for incompressible fluids. However, this method requires high computing power and is suitable for calculating simple turbulent motions with low Reynolds numbers, such as channel or circular tube turbulence.

Of course, there is the third "RNGκ-ε model", the fourth "Spalart-Allmaras turbulence model", the fifth method "internal and external iteration method" and so on.

Human creativity is unlimited, but there are only a few algorithms that are truly meaningful and have application value.

"Are you looking at the turbulence problem? This thing is not ordinary complicated!"

Zhao Qingfeng glanced at his screen, and said with great interest: "I have also studied this aspect, the core reason is that the problem itself is too difficult, strong nonlinear, infinite dimensional system, chaotic system, these three difficulties are currently There are no very suitable mathematical tools."

"So if you want to do it, I don't have any particularly good suggestions for you."

"I know, just take a look." Zhang Yuan said hastily.

Brother Zhao smiled, feeling that it is good to be young, if it was him, he would definitely stay away from such problems.

But he didn't care too much, there are many things, as long as he understands them, he will retreat in spite of difficulties.