The military-industrial scientific research system of the academic master.

Of course, Institute 240 and Han Chenfeng were not really planning to get it for free.

Although Chang Haonan does not need the help of an institution specializing in plasma research at the moment, as subsequent research becomes more in-depth, it is inevitable that he will be unable to cope with the less professional technical forces of the Aviation Propulsion Group and the Institute of Mechanics.

Therefore, to some extent, it can be said that Han Chenfeng really arrived at a good time.

If it were a few months or a year later, when Chang Haonan really took the initiative to look for partners, the competitive pressure would be much greater:

"Since Director Han has been studying plasma-related issues for many years, he should be familiar with the theory of magnetohydrodynamics, right?"

Han Chenfeng was a little confused by this sudden question, but he soon realized that this was actually equivalent to the other party giving a positive response.

So he nodded quickly:

"Of course. The method used to describe the interaction between magnetic fields and fluids is the most basic part of our work..."

Then he paused again, with a look of surprise in his eyes:

"But this is an approximate semi-theoretical and semi-empirical model... At least at this stage, related research basically assumes that the plasma Debye length is much smaller than its characteristic length and is an ideal continuous medium... If it is in a laboratory or even in a ground facility, then this premise can be considered to be approximately satisfied, but for an aircraft, it is probably not so easy to directly calculate a reliable result, right?"

"No no no..."

Chang Haonan waved his hand upon hearing this, stopping the other party from continuing:

"What you said is already the revised theory of magnetohydrodynamics..."

"After revision?"

The surprise in Han Chenfeng's eyes turned into confusion:

"If it is not corrected, it is just a direct combination of the NS equations describing the laws of fluid motion and the basic Maxwell equations describing the electromagnetic field..."

He originally wanted to say that this was a complete return to basics. Although the form was simple and beautiful, the solution of the NS equation alone was a huge problem that had troubled many generations of geniuses, not to mention the coupling of a Maxwell equation...

It is precisely because it is impossible to overcome the theoretical equations of magnetohydrodynamics (MHD) that researchers have developed various more complex, narrower but more operational correction forms.

If the equation can be solved directly, then at least 90% of researchers in related fields will no longer have to come to work...

However, considering that the person in front of him had won the Fields Medal after all, Han Chenfeng still considered some more possibilities:

"Hmm... Did you really solve the MHD equation?"

Although there was a bit of a joke in his question when he first asked it, by the time he finished speaking, the pressure of unemployment had already weighed on his mind.

"Of course not..."

Chang Haonan also felt that the other party was just talking casually, so he smiled and gave a negative answer.

Although this was the expected answer at the beginning, Han Chenfeng still secretly breathed a sigh of relief.

However, before he could regain his composure, Chang Haonan changed the subject:

"But you may have heard that I gave some regularity criteria for the NS equations a few years ago... In short, if the Leray-Hopf weak solution of the NS equations satisfies certain special conditions, then the weak solution is smooth on the existence interval."

"I……"

Han Chenfeng's breath got stuck in the middle, and he held it for a long time before he could breathe evenly:

"Theoretical mathematics is not my main research area... so I have only heard some rumors, but I don't really understand the cause and effect..."

"There is no causal relationship... In fact, until a few months ago, even I felt that this proof was far from any application and was only of pure mathematical value."

Chang Haonan seemed very frank:

"However, after paying attention to the MHD equation, I gradually discovered that if we make full use of the high regularity of the boundary value, we can avoid the Bernoulli criterion, thereby allowing the term corresponding to B in the MHD equation to be regarded as the external force term of the NS equation, without considering the contradiction between the change of the Bernoulli integral along the streamline under this assumption and the NS equation..."

The sentence consisted of only a hundred words, but it made Han Chenfeng, who was sitting on another sofa on the side, start thinking quickly.

Although his mathematical foundation was somewhat lacking and he could not understand how the other party proved the smoothness of the weak solution, if he skipped this step directly and believed in the correctness of this proof, he would be able to figure out some of the subsequent parts.

But Chang Haonan was obviously not going to keep the secret any longer, and revealed the answer before Han Chenfeng understood all the details:

"It can be proved that for a steady-state incompressible fluid in a two-dimensional bounded domain, the solution of the MHD equation must exist... In this way, it is equivalent to removing the two most fatal assumptions on the basis of the original plasma magnetohydrodynamic theoretical model..."

Having said this, the mess in the latter's mind was almost instantly sorted out:

“No need to assume that the plasma is a continuous medium and ignore the work done by the pressure?”

"That's right!"

Chang Haonan stood up and strode back to the desk:

"After removing these two, there are only six of the original eight basic assumptions left. Among them, the mean free path of particle collisions is much smaller than the characteristic dimension of the plasma, the plasma is stable and axisymmetric, and only two types of charged particles, electrons and ions, are considered. These three are inherently easy to meet for artificial plasma."

"The local thermodynamic equilibrium, single-fluid characteristics, and low magnetic field Reynolds number may be a big problem for you nuclear scientists, but the magnetic Reynolds number of an aircraft surface, let alone a normal aircraft, is less than one thousandth even for a hypersonic flow, and the ionization rate itself is negligible..."

When Chang Haonan finished speaking, the office suddenly fell into silence.

Han Chenfeng could even clearly hear his own heartbeat accelerating:

"So, we can calculate it according to the two-dimensional axisymmetric model..."

Although there are still some pure mathematics parts in the middle that I don’t fully understand.

But he still felt completely clear.

As the saying goes, the more you know, the more you discover your own ignorance.

After devoting himself to professional academic research, Han Chenfeng has almost forgotten the last time he had such a sudden enlightenment.

Although this is not his project or achievement, as a researcher in the field of plasma, nothing is more exciting than hearing about an academic progress that is truly valuable but will not cause him to lose his job.

Perhaps to confirm Chang Haonan's statement, at this moment, the laptop on the desk suddenly sounded a prompt.

Chang Haonan quickly clicked the mouse twice:

"The results of Yudu have been sent over."

Han Chenfeng instinctively wanted to get up and look over, but he didn't know whether he was aware of it or not. As a result, he was fixed in mid-air in a posture similar to a horse stance, unable to stand up or sit back. He was quite embarrassed for a moment.

But Chang Haonan did not have so many concerns. He simply turned the computer around and motioned for the other party to look.

The WS-10 plasma verification aircraft was originally developed jointly by the 606th Institute and the 240th Institute. Otherwise, even if Chang Haonan was free, he would not have chosen a place like Huairou Science City to meet.

Han Chenfeng took two steps forward and found that it was a radar reflection intensity curve with the horizontal axis as angle and the vertical axis as decibel value.

Or to be more precise, they are two lines, one real and one imaginary.

But the distance is very close,

Especially the part corresponding to the middle 60-120°, which almost completely overlap.

The legend below the axes indicates that the dashed lines are calculated values ​​and the solid lines are measured values.

Obviously, the gap between the two is almost negligible.

The picture was silent, but it silently showed the correctness of Chang Haonan's theory just now...

While being amazed, Han Chenfeng also thought with regret:

"It's a pity that it's too far from the requirements of a nuclear power plant. Otherwise, I might have seen fusion power generation become a reality in my lifetime..."

Controlled nuclear fusion is said to be "half a century away from practical use", which is enough to show how difficult it is to realize its engineering project.

Sometimes, even researchers themselves can't help but wonder whether they are striving for an unattainable goal.

Chang Haonan seemed to see through his inner thoughts and made a sudden turn of events as soon as he opened his mouth:

"Although it is not realistic to control fusion with the current theory, if you are willing, I do have an idea to directly use plasma to generate electricity. I am currently looking for someone to verify it..."