The military-industrial scientific research system of the academic master

Compared with the experienced Yu Hongru, Jiang Zonglin and Chen Hong's mentality is obviously much simpler.

It wasn't until Chang Haonan's speech ended that the two realized that the former was not prepared to choose between these two directions at all.

At the beginning, I was naturally surprised.

As long as there are enough resources, who wouldn’t want to do it in one step?

But the joyful mood did not last long.

After Yu Hongru retreated to the second line, they were the ones actually responsible for implementing the wind tunnel research and development after all.

And many problems cannot be solved simply by having money.

"Academician Chang."

After Chang Haonan's speech ended, Chen Hong took over the conversation first:

"I don't mean to target anyone... but the experience we accumulated in the JF8 and JF10 wind tunnels in the past is based on reverse detonation detonation technology, while forward detonation combined with the shock wave reflection principle affects the overall structure of the wind tunnel. The core technical route, if we want to achieve high total airflow temperature and long experimental time in the same wind tunnel, then the construction period..."

Everyone knows the speed of Chang Haonan's work.

If it takes four or five years to build a wind tunnel alone, it may be difficult to meet his requirements.

Therefore, even Jiang Zonglin, who was targeted without naming him, did not immediately refute.

After all, the problems Chen Hong mentioned do exist objectively.

But now that the project is right in front of him, he can't let go of this opportunity no matter what.

So, Jiang Zonglin gritted his teeth and stated firmly:

"The design methods of the shock wave reflector and auxiliary detonation section are indeed still at the stage of theoretical analysis and numerical simulation. To be implemented in the wind tunnel, more sufficient test data support is needed, but we have basically solved the problem of one-dimensional Application issues of combustion model under detonation wave conditions..."

"Academician Chang, you are an expert in the field of numerical calculation. You should know that in actual work, you can generalize the one-dimensional model to obtain the fundamental wave of the high-dimensional solution, so the efficiency should be much faster than expected... Me and my The team promises not to delay the entire project! ”

Chen Hong on the opposite side didn't really want to suppress Jiang Zonglin, so he didn't add insult to injury further.

Just waiting quietly for feedback from Yu Hongru or Chang Haonan.

"The JF10 wind tunnel has been in use for six years and is about to undergo routine maintenance and upgrades..."

Yu Hongru said and looked at Chen Hong:

"Xiao Chen, if you act quickly enough, you can put the two technologies of starting shock wave reflection control and shock wave/boundary layer pollution suppression into the JF10 wind tunnel for several rounds of testing first... wait until the other After progress is made in some of the studies, the specific design plan for the new wind tunnel will be considered together."

"As for Xiao Jiang..."

Speaking of which, he was a little stuck.

On the one hand, Jiang Zonglin, as his direct disciple, really couldn't show too much bias.

On the other hand, Yu Hongru has spent his entire career studying reverse detonation coupling detonation technology. He can only say that he has some understanding of the theory proposed by Jiang Zonglin, but he is really not sure of the specific progress.

Seeing the other party's embarrassed look, Chang Haonan quickly came to the rescue:

"Actually, Researcher Jiang doesn't have to worry too much about the progress."

As he spoke, he bent down and took out his laptop from his bag and put it on the table:

"The reason why I came here this time is actually to solve the theoretical problem of detonation calculation..."

Jiang Zonglin was stunned at first, and then quickly turned into surprise.

But he quickly controlled the expression on his face, as if he couldn't believe such a coincidence:

"Calculation...you mean the Chapman-Jouguet combustion equation?"

As we all know, combustion is essentially a redox reaction that produces heat and light.

Since the reaction itself generates heat, and the three elements of combustion include the ignition point, combustion can usually spread spontaneously when there are sufficient combustibles and combustion accelerants.

Traditionally, people refer to the low-speed combustion process as deflagration, and the high-speed and violent combustion process as detonation.

Therefore, problems such as the propagation and reflection of detonation waves are essentially a combustion problem.

If the Chapman-Jouguet combustion equation under high-dimensional conditions can be overcome, even partially, then many problems that originally required experiments can be solved on paper.

Chang Haonan smiled and nodded:

"That's right, some time ago, I specifically studied the self-similarity problem of the two-dimensional simplified C-J model with the help of high-dimensional conservation laws..." As he was talking, Jiang Zonglin had already taken the initiative to connect Chang Haonan's computer for the projection. instrument.

The original line of titles on the curtain suddenly disappeared and was replaced by a new page of PPT.

The above is an equation that is quite familiar to everyone here.

"Researcher Jiang just said that you have already studied the one-dimensional CJ ​​combustion model, so I will start directly from here..."

Chang Haonan turned around and gestured briefly, then continued:

"For the global solution of a type of n-dimensional combustion model, the initial boundary is an n-1-dimensional smooth manifold, which can be a curved bounded complex surface, or any other form that meets the requirements. In short, as long as it passes through the appropriate coordinates After transformation, the solution to the original equation can be reconstructed.”

"Considering the working characteristics of the wind tunnel, we will not consider higher-dimensional issues for the time being, and only limit this equation to two dimensions..."

"In the actual combustion process, the boundaries of combustibles are basically curves or surfaces... We construct a non-self-similar solution of the combustion model and analyze its complex geometric structure, comparing the high-dimensional non-self-similar solution with the one-dimensional self-similar solution The difference makes it easy to discover the new spatial structure characteristics of the detonation wave..."

"..."

Soon, a staged conclusion appeared on the PPT:

"If for any x∈R, [-Φ'(x)f(u+)+g(u+)]-[-Φ'(x)f(u-)+g(u-)]\u003e0 holds , then when q0\u003cQg, the combustion reaction only produces strong detonation waves, and the analytical solution of the two-dimensional C-J equation is..."

"..."

Jiang Zonglin is not a math major, so he was a little confused when he first faced the long paragraphs of derivation and calculation, as well as those expressions that could not be finished in one PPT page.

But Chang Haonan originally did not want to explain the entire process from a theoretical perspective.

Therefore, after ruling out the existence of self-similar solutions to the original equation and starting to discuss the detonation wave intensity and waveform on a case-by-case basis, the whole person became quite sober.

The pen in my hand also began to quickly record the contents of the PPT.

In the end, an expression with a very beautiful structure appeared in the notebook.

Jiang Zonglin looked at the final result of the two-dimensional equation in front of him and couldn't help but hold his breath:

"So... after adding the piecewise expression of q(t,x), the structure of the solution actually has the structural characteristics of a hyperbolic system of equations?"

For a moment, he even doubted the authenticity of all this.

Such a direct analysis process, I was not aware of it...

But when I thought about the nerve-wracking calculation process in the first half, I quickly felt relieved.

"It's more than that."

Chang Haonan changed the form of the solution and gave a preset initial condition:

"When strong detonation and detonation occur at the same time, the combustion wave interface and the weak discontinuity of the rarefaction wave behind the wave converge together to form a trifurcated structure. This is the result of the interaction of the three groups of waves."

At this time, Jiang Zonglin was already immersed in his own thoughts, and started the subsequent engineering analysis with flying colors.

Out of curiosity, several people leaned over to see the contents of Jiang Zonglin's notebook.

But he was stopped by Chang Haonan.

He knew very well that this kind of "flow" state was very rare, so he was not prepared to disturb the other party.

It was still early anyway.

The ten minutes of inspiration now may be comparable to the weeks or even months of following the steps in the future.

It wasn't until about half an hour later that the movements of Jiang Zonglin's hands gradually slowed down.

But in this room with a temperature of less than 20 degrees Celsius, his forehead was already covered with fine sweat.

It's enough to show how intensely the brain was working just now.

"I see……"

Jiang Zonglin raised his head again:

"The FC-WENO hybrid method can construct the hyperbolic conservation law equation under the single-region framework. Because the smooth and non-smooth areas under the single-region framework always change with the state of the numerical solution in the flow field, it can maximize the application of high-precision linear format to improve the accuracy and efficiency of calculations!”