Chapter 54 The organization has decided

If Chang Haonan just expressed this idea, it could only be regarded as "dare to think" at best.

But judging from what he just said about the manufacturing of compressor blades and turbine blades, he is definitely not talking nonsense.

At least it can be proven that he has conducted quite in-depth research on these seemingly unrelated fields of aerodynamics.

Being able to achieve this step can actually be said to be standing at the top of the pyramid.

And what he just said, "As long as you master the basic theory and methodology, you can conduct broader cross-border research" gave the four senior experts opposite a sense of enlightenment.

Director Zhou of the Commission of Science, Technology and Industry for National Defense instantly felt that he had found a treasure.

As the department in charge of the scientific research and production of aviation and shipbuilding military products, and the department that plans, coordinates and connects national defense scientific research, production and construction, the System Engineering Department No. 3 is in great need of such an all-round talent who can guide in the general direction.

She even had the urge to ask Jinghang University to directly assign him to the Commission of Science, Technology and Industry for National Defense after he graduated.

But her reason told her that now was not the time.

No matter how beautiful the words are, in the field of engineering technology, it is impossible to convince the public by relying on paper talk.

If you can't make anything, it's all in vain.

Therefore, the young genius in front of him still needs to go through the experience of specific model projects.

Thinking of this, Director Zhou looked at Yang Fenghata next to him.

As a model chief engineer, the latter's considerations are obviously more specific and practical.

Although he also saw Chang Haonan's talent, he continued to ask his questions.

"Comrade Xiao Chang, the idea you just mentioned should rely heavily on numerical calculation methods, but for some problems such as complex flow fields, have you considered the amount of calculations required in the numerical simulation process?"

This question may sound a bit awkward, but it is actually very practical.

It is now June 1996. Half a year later, in December 6, Intel will build the most powerful supercomputer at the time, ASCI Red, with a calculation speed of 1996 trillion operations per second.

As for China, the fastest supercomputer in 1996 was the Dawn 1000A, with a calculation speed of only 40 billion times per second.

For comparison, before Chang Haonan was reborn, the A14 processor on the iPhone 15 had a calculation speed of 15.8 trillion times per second.

One mobile phone is equivalent to 12 of the world's best supercomputers.

Therefore, the amount of calculation is indeed an issue that must be considered.

But this obviously couldn't stump Chang Haonan, who had been prepared for this.

"Of course I've considered it."

Chang Haonan stood up directly this time, walked to a blackboard on the side wall, and picked up a piece of chalk.

"Since you mentioned the problem of numerical simulation of complex flow fields, let's take the oscillatory motion of a delta wing under a dynamic flow field with a large angle of attack as an example."

Yang Fenghao raised his eyebrows and subconsciously sat up straight.

Chang Haonan did not choose this issue randomly as an example.

This is a very valuable question for the ongoing J-8-3 project.

And opposite Yang Fenghata himself is very proficient in aerodynamic analysis of high angle of attack.

So he must be interested in it.

Of course, the identity of the chief designer of the J-8-3 has not been publicly publicized at this time. In the opening stage, he was only introduced as an expert from the 601 Institute. Therefore, Chang Haonan ostensibly chose it just because of the other party's question. That's just the problem.

"If the CFD method is used to directly calculate the dynamic flow field at large angles of attack, the computing resources and computing cycles required will be very large. Therefore, a simpler model that can directly predict the important characteristics of the system is needed instead, that is, the model reduces the Level…”

“So I designed a signal-based reduced-order model, the Volterra series model, by referring to the nonlinear identification and modeling process of electronic circuits. The basic principle is: for the time-domain discrete Volterra series, The output y(n) of any input u(n) can be expressed in the following way..."

Chang Haonan said and wrote a long multiple convolution on the blackboard.

"It can be seen that if all the Volterra cores of the system are obtained, then the response to any input of the system can be obtained. Considering that the length of the series and the model memory length increase rapidly with the increase of the core order, it is not conducive to Volterra To identify the Volterra core, we cut off the part above the second order, and then perform wavelet compression on the remaining Volterra core..."

After he erased the blackboard and refilled it for the sixth time, the reduced-order method, which could greatly simplify the calculation process, was finally finished.

Liang Zhuoping and Director Zhou, who had been out of technical positions for a long time, looked more confused.

But the eyes of Du Yishan and Yang Fenghao were almost full of... fanaticism.

The flow field calculation of a delta-wing aircraft is inherently much more complex than that of a straight wing.

Let alone numerical calculations, even analysis is quite difficult.

So it mainly depends on experience.

And if you want to gain experience, you have to spend money on a lot of wind tunnel testing and test flights.

It also takes a lot of time.

If the reduced-order model that Chang Haonan just wrote on the blackboard can work, it will undoubtedly save a lot of trial and error and obstacles.

This is simply tailor-made for the J-8-3.

And it's a brand new engineering model.

In fact, this time it can be said to be engineering theory.

Because this idea of ​​reducing the order of the model is not limited to Volterra series, it can be extended to more fields.

Of course, this still needs to be verified.

However, with the previous project of 603 Institute as a basis, everyone is still optimistic about the verification results.

In other words, within one month, Chang Haonan produced groundbreaking results twice.

This undoubtedly shows that what he mentioned before about “mastering basic theories and methodologies” is not groundless.

It's just that some theories may need to be put forward by himself.

Yang Fenghao had an idea at this time:

I want to settle on this guy!

He turned his head and consulted the other three people with his eyes.

All were answered in the affirmative.

"Comrade Xiao Chang, there is now a key national defense project assigned to Academician Du's research team. Are you interested in participating in this project?"

Although judging from Du Yishan's description and the recent contact with Chang Haonan, Yang Fenghao is basically 100% sure that the latter will agree, but the process will eventually go ahead.

"Before you make a decision, we need to explain it first. If you choose to participate in this project, there will be certain restrictions on subsequent work, going abroad, and publication of results..."

Chang Haonan naturally knows these contents very well. After all, his actual working time in China Aviation Industry is not shorter than that of Yang Fenghao.

So after the other party finished speaking, he agreed almost without thinking and signed an informed document.

"So, Xiao Chang."

After Chang Haonan signed his name, Du Yishan left his seat and walked to him:

"The organization has decided that you and Xiao Yao will jointly represent our research group to participate in the research and development of Project 83!"