From Almighty Scholar to Chief Scientist

However, obviously, this has very high requirements on the computing power of the computer, and once the turbulent flow becomes complicated, it is difficult to obtain the desired results by direct numerical simulation, so it can only be used to simulate relatively simple turbulent flows Model.

"You see, we performed DNS on the turbulence model, and the final result is very stable, and even our nuclear submarine can reach a speed of up to 60 knots."

"Ah."

Looking at the value displayed on this model, Lin Xiao nodded, it is indeed very good.

The current speed of nuclear submarines is about 30-40 knots. If their nuclear submarines can reach a speed of 60 knots, it will be nearly twice the speed. The boats couldn't keep up.

However, next, Ma Weimin opened another file, "This is our last water test, a total of ten times, and every time the situation I said before appeared."

Lin Xiao nodded, opened the file, and read it.

Sure enough, it was normal for the first hour, but there will be problems at some point after that.

Looking at this result, Lin Xiao fell into thinking.

The problem is huge.

Why is there such a situation?

Undoubtedly, this is a very counterintuitive thing.

It has been running stably for so long, why did it suddenly become disordered?

The reason for the electromagnetic field?

Or fluid force?

Immediately, Lin Xiao also felt a little troubled.

Finally, he found a piece of paper from the side, and then began to draw the model and force analysis on the paper with a pen.

Seeing that Lin Xiao was thinking about it, Ma Weimin stood beside him and didn't bother him. For this kind of problem that may involve top-level mathematical problems, although he has made many achievements, he can only leave it to Lin Xiao at this time. This specialist is gone.

When the people around saw Lin Xiao solving the problem, they all gathered around and looked at what Lin Xiao had drawn on the paper.

They all know how difficult the problems they encounter are to solve, so although they seem to have something to do, they are basically fishing.

Now seeing a big shot coming, they are of course very curious.

And that's it, over time.

After a while, Lin Xiao suddenly raised his head and said, "Send your turbulence model, and I'll add something to it."

Ma Weimin immediately sent their turbulence mathematical model to Lin Xiao.

And Lin Xiao modified some items in it, and then put it on the software to start testing.

At the beginning, the turbulent flow in the software was still stable, but after about 1 minute, the turbulent flow suddenly became disordered.

Seeing this scene, Ma Weimin and other people around suddenly showed expressions of surprise.

Lin Xiao found out the reason just after getting started?

But just as they thought about it, the turbulence on the software became more stable.

The audience suddenly fell silent again.

Chapter 349 Gradually understand everything (cross out)

Looking at the turbulence model that had returned to the previous stable state, everyone present knew that Lin Xiao's model still failed.

Of course, at least the failure was not so complete, after all, there was still turbulence in the process.

Ma Weimin stepped forward and asked, "How is it? What is the specific situation? Why did the turbulence suddenly appear just now?"

Lin Xiao frowned, and said: "I mainly added some new things to it just now. The turbulent flow before you just regarded the electromagnetic force as a general Newtonian force, and did not conduct special analysis. Then I added the magnetic field of the superconductor. After taking it into consideration, this kind of problem arises.”

"It means that the electromagnetic force caused this situation?"

Ma Weimin frowned and began to think.

From a macroscopic point of view, the magnetic field generated by the superconducting coil in the magnetic fluid thruster can directly regard the force generated by the conductive seawater as a complete force.

But as we all know, according to quantum mechanics, the world is discontinuous, and the force is also a part. The electromagnetic force generated by the superconducting magnetic field is obviously different everywhere.

If you think about it that way, it does seem possible that this could be the case.

But then Ma Weimin still had doubts: "But this situation is not very consistent with Newtonian mechanics, right? Even if it is a little disordered, I can understand it, but such a particularly disordered situation that leads to a sharp drop in speed is really a bit Incomprehensible."

"Yes, I also have some difficulty understanding."

Lin Xiao nodded, then stroked his chin, lost in thought.

This question made him feel a little puzzled.

Then, he re-wrote a formula on the scratch paper, which was the Navier-Stokes equation.

Looking at this complex but full of mathematical beauty partial differential equation, Lin Xiao shook his head.

Although it is now considered that the problem is caused by the force of the superconducting magnetic field, it is obviously related to the interaction force between fluids.

After all, the direct cause is caused by the fluid force, and the electromagnetic force only indirectly drives the conductive seawater to produce this change.

Of course, such an effect that cannot be explained but has a very magical effect still aroused Lin Xiao's other thoughts.

Perhaps, this is a new physical effect that has never been discovered before, and it is not simply an accidental mechanical problem.

Just like the Hall effect.

Perhaps, when they unravel the principle of this miraculous phenomenon and master it, they will be able to play a role in other places?

Thinking of this, Lin Xiao also raised his attention a little bit, and then refocused his attention on the Navier Stokes equation in front of him, and felt troubled in his heart: "Could it be possible, do we really need to solve this thing?"

However, soon, he made a decision.

Research and research first. If some staged results are obtained during the research process, maybe it can solve the current problem?

Then he said to Ma Weimin: "Academician Ma, let's do this first. I'll think about it when I go back. You can also study it experimentally. Since this matter may be related to electromagnetic force, you may be able to change the magnetic field. Or when the liquid enters the channel, perform some diversion operations, or deal with it."

"okay, I get it."

Ma Weimin nodded, "We will conduct a test soon and send you the results."

"Ah."

Lin Xiao nodded, and then left the laboratory.

……

In the following time, Lin Xiao entered into the research of the Navier Stokes equation.

Anyway, since he solved the artificial nerve and made Shi Hao stand up, he has entered a state of rest again, and the next time is just right to study this mathematical problem.

Of course, it's not that simple.

"Professor, are you... studying the Navier-Stokes equation?"

In Beijing University, in Lin Xiao's office, Chen Mingkai looked at what his professor was researching, which seemed very complicated, and he couldn't help showing curiosity on his face.

Lin Xiao nodded and said, "Yes."

"Then what are you studying? Some kind of application?"

"Uh... no." Lin Xiao said, "Prove the existence and smoothness of its solution."

"Oh, this..." Chen Mingkai suddenly realized, but suddenly he realized, and his face showed a look of shock: "You mean...that millennium problem?"

"Ahem, don't be so surprised, calm down, it's not like I haven't proved the Millennium Problem before." Lin Xiao smiled, and then said: "What's more, it's just proving a Millennium Problem, not solving it. understanding."

Chen Mingkai immediately rolled his eyes.

My own teacher is good at everything, but he is too awesome.

Of course, as Lin Xiao said, the difficulty of "proving the existence and smoothness of the solution of the Navier-Stokes equation" in the Millennium Prize problem is more difficult than that of the Navier-Stokes equation. The general solution is still a little simpler.

The Navier-Stokes equation is a partial differential equation. Solving partial differential equations is a direction often studied by mathematicians in this field, and this is relatively difficult.

It is even more difficult to solve the Navier-Stokes equation, and it is almost considered impossible to solve the problem.

Because it is not as easy to find a general solution as the Euler equation, because there is an extra second-order derivative term μ△v in the Navier-Stokes equation, so it is difficult to find it except under some specific conditions. Its general solution.

Therefore, in the Millennium Prize problem, it is only required to prove the existence of its solution, but not to find out what its general solution is. As for the so-called smoothness, it means that the final general solution can be written as a [smooth function], which has Infinite derivability, just like the derivative of e^x is itself.

And once the general solution is solved, it will be terrible. All things related to fluid mechanics will be greatly simplified. For example, the flow of water can be easily described by this general solution, or the The aerodynamic optimization and so on, the process will be greatly simplified.

However, it is precisely because it is very difficult to find a general solution, so few people study this direction.

And Chen Mingkai never thought that his teacher could find this general solution, so he asked, "Professor, have you found a proof method?"

"No."

Lin Xiao said, then glanced at Chen Mingkai, and said angrily: "What are you doing here when you have nothing to do? Have you chosen the topic for your thesis? You have to choose it before July."

"Ah this..."

Chen Mingkai was taken aback, and then quickly said: "The selection will be made soon, professor, don't worry, I promise I won't procrastinate."

Seeing this guy running away, Lin Xiao shook his head with a smile, then stopped thinking about it and continued to study the Navier-Stokes equation.

"If the current method doesn't work... Maybe I should change my thinking?"

"Well... let's start with the special solution first."

The special solutions of the NS equations basically belong to the parallel flow in the simplest case.

The representative flow in this respect is the Hagen-Poiseuille flow in a circular tube and the Couette flow between two parallel plates.

Lin Xiao found these two special solutions.

The first is the Hagen-Poiseuille flow, which belongs to the pipe flow, that is, the flow in a circular pipe. This flow is obviously relatively simple.

[u=－△p/(4μL)(D^z/4－r^z)】

【Q=－π△pD...】

Write down a few lines of formulas, according to these formulas, Lin Xiao also directly imagined a tube in his mind, and then there is liquid inside, flowing along this tube.

Then he looked at the Couette flow again, and then used the same method to first build a model in his mind, and then directly simulated it.

"Well... this kind of fluid is relatively simple, what if we change it to something more complicated?"

For example, the magnetic fluid propulsion that Ma Weimin and his colleagues plan to study.

It is to use conductive water as a magnetic fluid, and then propulsion can be achieved through reaction force.

Lin Xiao began to try to use his brain to simulate, but this is obviously quite complicated. After simulating in his mind for a long time, the load is almost 100%, and what can be simulated is still very limited.

Of course, if he slowly "loaded" it, he could barely achieve it.

Just like that, his eyes suddenly lit up.

Then he quickly picked up the pen and made another improvement to the original turbulence model.

Afterwards, he put the model on the software and started loading and running.

Still the same, it was stable at first, but as time passed, all of a sudden, the liquid started to move wildly, very unstable.

And this turbulence lasted for more than ten minutes.

After more than ten minutes, it returned to its original stable flow state again.

Seeing this, Lin Xiao was not surprised.

However, there was a smile on his face.

He gradually understood everything (crossed out) - he gradually understood the nature of these fluids.

3 Chapter Fifty: Kong Huaan, whose interests have changed?

At this time, Lin Xiao, through the establishment of the turbulent flow in the channel of the magnetic fluid thruster in his mind, finally found such a faint thing that can be used to explain these fluids.

Looking at the turbulent flow model on the software, Lin Xiao's heart moved slightly.

"So, this fluid model can be further changed."

Lin Xiao took out the pen again, changed the original turbulence model, and then put this model on the software again for simulation.

But this time, compared to the previous turbulence states that did not last long, this time it lasted for a long time, lasting nearly half an hour.

However, Lin Xiao was still a little dissatisfied with this, and continued to modify the turbulent flow model, and then got a brand new model. After re-simulation, after a period of smooth flow, the turbulent flow appeared again, and this time, for a whole It went on for almost two hours.

"Still not perfect."