Chapter 89

John continued: "your father's algorithm is indeed the most outstanding work of mankind, but it is far from powerful enough. So, we can't make the nuclear fusion device smaller. Every reactor is like a mountain. It's too rough. "

Zhang Yuan looked at the turbulence, some bright, some dim, and some are spinning, lost in thought.

Convinced or not, John's complaint is right.

He had a little ambition in his heart, just like a seed.

"The problem my father once did, maybe Can I too? "

Turbulence is the last mountain in classical physics. About 400 years ago, Navier Stokes equation, also known as N-S equation, has been a theoretical description of fluid physics. It is difficult to find the exact solution of this equation, so scientists usually use some simplified theoretical models or resort to numerical simulation methods to predict fluid motion.

However, it is not accurate to use the simplified model to simulate the plasma turbulence. If the plasma is not well constrained, it will cause great damage to the fusion engine.

With the rapid development of Informatics, the turbulence problem has become a little loose, but it is only a little loose. It can simulate more accurately, but it can't understand its real essence.

John sighed: "we may never find the exact mathematical solution to the turbulence problem, or the exact solution is hidden in the more microscopic probability superposition state. With our ability, we don't know at all."

John Wilson is a typical representative of pessimists.

He believes that the upper limit of human science and technology is probably the same as it is now. With human intelligence, we can only go around in such a small circle.

Although there are still some details to be polished, it is impossible to achieve real qualitative change.

So, these pessimistic scientists want to get on the spaceship and see the world three thousand years from now.

This is not unreasonable. It took 400 years to solve a turbulence problem.

In cutting-edge physics, in addition to the vitality of condensed matter, others have gradually declined. High energy physics is plagued by the "energy level desert". Other disciplines, such as chemistry and semiconductors, actually use some approximate theories. The most important thing is that these approximate theories can indeed solve some problems.

As for mathematics, it is also on the decline.

Riemann conjecture, 400 years standing; Goldbach conjecture, 600 years.

So far, the "great unification of mathematics" project is only a framework, and it is still tens of billions of light years away from completion.

The new civilization school believes that the present 23rd century, together with the 24th and 25th centuries, is likely to be the last golden age of mankind. Next, human intelligence as a whole cannot continue to develop.

Once the development of science and technology stagnates, human civilization is likely to have the phenomenon of historical reincarnation, just like the ancient Xia state. With academic words, that is to say, falling into the "trap of mediocrity", it is difficult to make great historical progress.

In fact, Zhang Yuan quite agrees with some views of the new civilization school, but he is neither pessimistic nor optimistic about this issue.

In fact, he doesn't believe that human beings will be so stupid that they will fall into foreseeable traps. It's hard to imagine what the world will be like in the future. Maybe there will be some technologies to transform intelligence.

In addition, his direction is more inclined to engineering and technology. Technology and science are very different. There is still a lot of room for the improvement of human application technology.

"Zhang, you are too optimistic."

John shrugged his shoulders and said helplessly: "in history, there are many phenomena, such as La beautification, middle-income trap and so on. Even if some countries clearly know it, they still can't cross it, because many things in a country can't be done when leaders are aware of it. It depends on the strength of the whole. "

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

"Yes, you're right." Zhang Yuandao: "but we have to be optimistic, don't we? Pessimism will not solve any problem. "

After saying goodbye to the sentimental elder martial brother John, Zhang Yuan returned to his laboratory seat and began 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 problems that can not be solved. For example, "3x + 1" conjecture, happy ending problem, Gauss circle problem, Erdos Graham ternary problem Any one is as difficult as Li guess.

I don't know why, looking at countless problems, Zhang Yuan always has a slight sense of anger in his heart.

Perhaps, as a member of the scientific research workers, can not thoroughly penetrate the natural instinctive anger.

Zhang Yuan squeezed his fist secretly.

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

It doesn't matter whether you get or lose, just follow your own heart."Turbulence problem!"

"Have a try!"

It takes a lot of courage.

It probably took a lot of time, and nothing could be achieved, so the sunk cost was huge. Only young people like him, with a cavity of blood, can go forward bravely.

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

From a purely mathematical point of view, there is basically no great possibility.

Zhang Yuan doesn't feel that his current strength is able to write more accurate and effective equations than the N-S equation.

"Maybe we can create some informatics methods to solve this problem."

The first method is the famous "spectrum method of wavelet transform" used by my father, which is also the best algorithm in engineering application. It successfully solved the problem of multi-scale turbulence simulation in time and space.

In essence, it refers to the transmission process of signal in neurons to describe the burst mechanism of turbulence in pipes.

The second method is direct numerical method.

By solving the "N-S equation" of incompressible fluid, the isotropic turbulence in a three-dimensional periodic cube is simulated. However, this method requires high computational force and is suitable for simple turbulent motion with low Reynolds number, such as channel or tube turbulence.

Of course, there are the third "RNG κ - ε model", the fourth "spalart allmaras turbulence model", the fifth "internal and external iteration method", and so on.

Human creativity is infinite, but there are only a few algorithms that are really meaningful and valuable.

"You're looking at turbulence? It's not so 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. There are no very suitable mathematical tools for the three difficulties of strong nonlinearity, infinite dimensional system and chaotic system."

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

"I know. Just look around." Zhang Yuanlian was busy.

Elder martial brother Zhao laughed and said, "it's good to be young. If it was him, he would be far away from this kind of problem.".

However, he did not care too much, there are many things, as long as the understanding, will retreat.