Great Country Academician

Xu Chuan didn't care too much about the theft of his manuscript, after all, it was part of the plan.

In the evening of the same day, Zheng Hai sent back the lost manuscript.

Although Xu Chuan was a little curious about which country's people stole his manuscript from him, it was just that the security personnel were still dealing with it, so he was not easy to ask.

The days passed day by day, and the modeling work for the plasma turbulence of the controllable nuclear fusion reactor was carried out a little bit.

In mid-September, half a month later, the raw data of inertial neutrinos jointly analyzed by Nanjing University and Jiaotong University was completed.

Chen Zhengping immediately called Xu Chuan and handed over the analyzed data to him.

"The analysis data has been sent to you, but the amount of analyzed data is still relatively large. After all, this is the special collision mathematics at the LHC. Do you need our help?" In the office, Chen Zhengping looked at Xu Chuan and asked.

The discovery of inertial neutrinos, whether it is for Xu Chuan, Nanjing University, or for the entire Huaguo, the sooner the better. Because no matter from which aspect, the direction of inert neutrinos has greatly enhanced the academic influence of individuals, schools, and countries in the academic world.

Xu Chuan thought for a while, and said: "That's fine. In this way, I will compile a document on how to distinguish and confirm the confidence of inert neutrinos, and then you will process according to the document, and I will prepare the processed data. How is Dariztu?"

Chen Zhengping nodded: "It's absolutely possible. At present, the most important thing is to increase the confidence level of inert neutrinos from 3 sigma to 5 sigma or more as soon as possible."

Xu Chuan smiled and said, "Then I will trouble the teacher."

Compared with last year's Chinese New Year, he really didn't have much time to deal with the data of inertial neutrinos.

At present, it is more important for him to seize the time to complete the modeling of plasma turbulence, and it is indeed easier to hand over the data analysis of inert neutrinos to Nanjing University and Jiaotong University.

Chen Zhengping said with a smile: "You don't have to be so polite. In fact, we have to thank you for giving me this opportunity. After all, for other students, this is rare experimental data."

For Nanjing University and Jiaotong University, it is also a very good thing to let physics students who have no chance to participate in CERN experiment data analysis to participate in some high-energy physics data analysis work.

After all, not every student who studies theoretical physics has the opportunity to follow their tutor or apply for an internship at CERN.

More theoretical physics students often spend a little experimental experience in China or other places to complete their graduation thesis.

And this time, the analysis data of light-inert neutrinos is enough for a large group of physics students of Nanjing University and Jiaotong University to complete their graduation thesis. Maybe even take this opportunity to get the qualification to set foot on CERN.

As Nanjing University and Jiaotong University began to analyze the experimental data of sterile neutrinos in depth, Xu Chuan's mathematical modeling of plasma turbulence has gradually come to an end.

It is difficult to establish a mathematical model for plasma turbulence, even if the underlying complex mathematical calculations and related theoretical foundations are aside.

During the modeling process, Xu Chuan encountered a lot of troubles.

Some things can be solved with all kinds of searching and learning, but some problems simply can't find the answer on the Internet.

For example, when embedding "eddy current direct simulation data" into the model, he encountered difficulties.

Because there are differences between the size scales of the eddies, and the solution must solve for both, this makes it very expensive to solve for all turbulence scales in a numerical simulation.

Especially when it is used to solve high Reynolds number flow, even with a supercomputer, it may not be able to complete the calculation in a short time.

If it's other fields, it doesn't matter.

But for real-time control of high-temperature plasma turbulence in a controllable fusion reactor, timeliness is life.

Without real-time control, it will be too late to say anything after the plasma hits the first wall.

Looking at the crude model on the screen and the half-written modeling program, Xu Chuan let out a sigh of relief in his chest.

To be honest, he has been bothering with this problem for a long time, but he can skip it and do other work before, but now he has to make up.

"Maybe, I need some foreign aid." Staring at the slowly rotating model on the screen, Xu Chuan shook his head slightly.

Strictly speaking, he has not studied mathematical modeling comprehensively and systematically. He can do some simple model writing, but it can be said that it is almost impossible to solve this problem based on his own ability.

Of course, it is normal to seek advice and help when encountering problems in research, and there is no shame in it.

Just saying, who is better to ask for help?

After thinking for a while, a figure appeared in Xu Chuan's mind. After confirming, he opened the mailbox, sorted out the problems he encountered, the conditions he needed, and some relevant theoretical data and foundations, and sent them over.

Then he picked up his phone again, opened Weixin, found a familiar number, and sent a message.

After a while, the phone vibrated, and a Weixin replied.

"Well, I received your email, I'll take a look first, but it may not be resolved."

Xu Chuan smiled and replied, "Thank you for your hard work. I will treat you to dinner when you come back."

For the work on mathematical modeling, the first thing he can think of is the senior sister Liu Jiaxin.

He returned to China in 2018, and his senior sister went to Princeton for further study. It has been more than a year now.

With her mathematical talent and learning ability, she presumably could learn a lot in Princeton, and maybe she could help him solve this problem.

Putting down his phone, Xu Chuan returned his attention to modeling. Although I asked someone to help me take a look, it is necessary to study it myself.

After all, knowledge is something that is never afraid of too much, but only hates less when it is used.

The senior sister's reply was much earlier than Xu Chuan expected. In the evening, an email to keep an eye on was replied.

At the same time, he also received a message from his senior on his mobile phone: "Well, the plan has been sent to your email address. You can see if it suits you. If it doesn't work, you can talk to me again."

Xu Chuan was eating when he received the prestige letter. After replying with a good reply, he cleaned up the food on the plate and hurried back to the office.

Opening the mailbox, there was indeed an unread email lying in it.

After clicking on the email, Xu Chuan quickly browsed through it.

".According to the requirements, if you need to simulate the 'direct value of the eddy current', whether you use the DNS simulation, the LES split method, or the Reynolds average simulation RANS method cannot achieve the required results."

"Because the characteristic Reynolds number in plasma turbulence engineering problems is generally high, even the largest scale in the attached boundary layer will become very small, even if the LES model is used, the grid scale requirement is not much weaker than that of DNS .”

"It's a core fundamental question."

"And if you want to reduce the requirements for computer hardware and computing power, maybe you can try to use an anisotropic model near the boundary layer, such as the RANS model, and use the LES model in the area far away from the wall, through double mixing. Complete an architecture for reviving high-level models"

". Let the Reynolds stress term τ=ρR^ij "$^$" represent the Favre average, and the six-component equation has the following general form:

【ρR^ij/t+(ρu^kR^ij)/xk=ρPij+ρΠij+ρεij】

"The right end is the generation term, the redistribution term of the pressure and strain correlation term, the dissipation term, the diffusion term and the mass term, among which the generation term can accurately obtain the required function."

"The transition function F is introduced to make the RANS method act near the boundary layer, and the LES method is used in the area far from the boundary layer, and the second-order moment model under the hybrid RANS/LES framework can be constructed:"

【R^hybridij=FR^ij+(1F)R^sgsij. 】

".Perhaps such a higher-order moment model has the potential to accurately resolve eddy flow, which meets your requirements."

"I hope it can help you a little."

In front of the computer, Xu Chuan carefully read the solution delivered by Liu Jiaxin.

Maybe it's because the experience of studying abroad for more than a year has affected some of my personality, or it's through the computer screen, or it's just in my own professional field. too much.

Of course, I have to say that the solution proposed in this email may really solve his problem!

It is not only detailed, but also lists some key nodes in the modeling.

And being able to make such a detailed plan in just a few hours, it is conceivable that not only she has a deep understanding and high ability in modeling.

It is even more likely that after receiving his email, he has been working hard to solve this problem. Otherwise, it would take a few hours to make such a plan with detailed nodes, which would be impossible.

After reading the email, Xu Chuanlianshan quickly replied with a smile: "I have received it, I will try it first, and I will tell you whether it succeeds or fails."

"I have a hunch that it can help me solve this trouble. Thank you for your hard work."

After downloading the scheme from the mailbox, Xu Chuan reopened the FloEFD modeling tool, and after making a backup of the original model, he began to re-modify and write the mathematical model following the idea of ​​his senior sister.

This time, the modeling process went fairly smoothly.

When he typed the last line of calculation on the computer and carefully saved the finished model, he relaxed.

After heaving a sigh of relief, Xu Chuan put down the ballpoint pen he was holding on his fingertips, and looked at the mathematical model on the display screen, with a smile on his face.

"Finally done!"

After stretching and exercising his muscles, Xu Chuan checked the mathematical model he made, and after confirming that there was no problem, he copied it.

He left the office with the solid-state drive where the model was stored.

The mathematical model has been completed, so the next step is to conduct a simulation test on it.

And this requires the use of supercomputers. To run this model, even if it is only to calculate and deduce the phenomenological data, the computing power required is far beyond the reach of the human brain.

Unless his brain is a sixteen-core quantum computer, this is simply impossible.

As a top 985 university, Southern Nature has its own supercomputer.

NTU’s high-performance computing center uses IBM’s large-scale blade cluster, with a peak theoretical calculation of 873.6 trillion times per second, providing computing services for NTU’s departments of physics, chemistry, atmosphere, astronomy, materials, and electronics.

Although its performance is not considered excellent now, but it is still possible to test the mathematical model "should" in his hands?

Of course, Xu Chuan is actually not sure whether the supercomputing at Nanjing University can drive his model, because calculations involving turbulence have always been the most complex and computationally demanding of all calculations.

Even if he has made the model the simplest one after another, the test for supercomputing is probably quite large.

The peak value of theoretical calculation is 34 trillion times per second. For a mathematical model of turbulent flow simulation control, this calculation power is really not much, and it can even be said to be pitifully small.

Perhaps he should go directly to a large national supercomputing center to do this test, but in comparison, that would be a lot of trouble, and he may even have to wait in line if he fails.

But Nanjing University is different. As long as he needs it, it is just a matter of stopping all other calculations to serve him exclusively, so he is going to try it at Nanjing University first.

Give it a try, you won't get pregnant anyway.

With the model, Xu Chuan found the teacher in charge of supercomputing center in the administrative center, and after filling out a supercomputing application form, the teacher in charge of approval stamped a red stamp on the application form with a bang.

This person's application form, as long as he doesn't want to use a supercomputer to play games, 100% will be passed directly.

What's more, the teacher who stamped the seal even took a glance at the application content.

"Testing a mathematical model of plasma turbulence."

Although he is not a professional, the teacher who is engaged in administration still knows the name of plasma turbulence, which is a world-renowned problem.

In this case, he passed without even reporting to the leader.

For fear of delaying this research.

After all, the report can be made up after the fact, but if the matter of the boss is delayed, the principal may hang him at the school gate and beat him.