Chapter 1213 A big problem solved by a piece of paper

There is only one sentence written on such a large piece of paper. If it were written under normal circumstances, it would really seem a bit incoherent.

After all, when doing things in the academic circle, the six elements of title, abstract, introduction, main text, conclusion and citations should be complete to make it look decent.

Even the industry's forefathers generally don't break this rule.

But considering that the Gaofei Group is currently struggling with the problem of the flow field characteristics of the bomb bay, this sentence is like timely help.

What's more, there is Chang Haonan's signature in the lower right corner of the white paper.

There was only a moment of hesitation in Jiang Jianjun's eyes, and then he made a decision in his heart.

Qiao Chenqing, who was standing beside him, had already understood the meaning of the words on the paper:

"Is this... the solution to the problem we just discussed?"

"Yes."

Although it sounded like he knew the answer but it was his leader who asked the question after all, so Jiang Jianjun quickly stopped preparing to ask someone to do something and gave an affirmative answer.

Qiao Chenqing couldn't help but look shocked.

Although he had heard of Chang Haonan's deeds more than once, seeing it with his own eyes today still made him feel that it was a bit exaggerated.

You should know that the other party did not directly intervene in the modification of this Tu-160 throughout the whole process.

Now, suddenly a letter is sent along with the design parameters of the verification missile, and it just happens to be the biggest trouble we are facing here?

The last time Qiao Chenqing heard of such a thing was when he was a child, when a storyteller told him about the ingenious strategies in Romance of the Three Kingdoms...

"Then...how is it feasible?"

At this moment, he didn't care about continuing to act like a leader and asked immediately.

Jiang Jianjun was stunned, and then replied helplessly:

"Commander, I just saw this letter a few minutes ago, how can I know immediately..."

At this time, Qiao Chenqing also realized that he was a little anxious, so he prepared to make up for it by saying a few words so as not to put too much pressure on the other party.

But before he could open his mouth, he heard Jiang Jianjun change the subject:

"However, in principle, if the inclination angle of the rear wall of the embedded weapons bay is large enough, the bay structure will no longer be a typical cavity in aerodynamics, and the problem will naturally be solved... However, if you want to achieve this effect by simply changing the inclination angle, you need an angle of about 70 degrees, which is equivalent to directly occupying half or even more of the effective space in the weapons bay, which is not feasible in engineering."

"As for the combination with the leading edge spoiler..."

The latter showed a bit of shame on his face:

“It’s an idea we haven’t tried before.”

Qiao Chenqing naturally would not criticize the other party for such a thing, and what he was most interested in now was not the issue itself.

"Comrade Jianjun, you have worked in the aviation industry for a long time, so I would like to ask you one more question..."

He softened his tone a little:

"Doctor Chang...did he often do this before?"

"What I mean is that even though we are far away, we can still provide guidance on how to carry out the work."

Jiang Jianjun scratched his head, his expression looking a little twisted:

"The last time I worked on a project with Academician Chang was in 97. At that time, we had to modify the H-6 into a water-spraying test aircraft to simulate icing... The task was not complicated, and Academician Chang seemed to have not graduated yet, so I didn't have a deep impression of it."

"But after listening to Mr. Liang who was transferred from Nanzheng after the merger, it seems that the difference is not too big..."

For a moment, neither of them knew what to say next.

Then, there was silence again.

In the end, it was Qiao Chenqing who broke the deadlock:

"Then the next step is to re-conduct the flight test according to the ideas given by Academician Chang?"

Seeing that the topic had finally returned to something he was familiar with, Jiang Jianjun breathed a sigh of relief:

"That's not it."

He shook his head:

"Even if it is the suggestion given by Academician Chang, we can't take the risk of flying the aircraft directly. We must first conduct numerical simulation and wind tunnel testing to at least verify the feasibility and safety of this plan."

In fact, when Qiao Chenqing asked this question, he was already ready to stand up and end the survey.

But after hearing the answer, he sat back down again, a hint of curiosity in his eyes.

When he was serving in the Air Force of the Beijing Military Region in his early years, he heard a report given by the Aviation Industry Corporation of China, which mentioned the use of computer simulation technology to improve test flight accuracy and reduce a lot of unnecessary test flight time.

So some ideas on this:

"Numerical simulation...will the results be available soon?"

Jiang Jianjun raised his eyes slightly, and seeing Qiao Chenqing's expectant face, he immediately guessed that the other party wanted to stay and see the result with his own eyes, and he couldn't help but smile bitterly in his heart -

Numerical simulation can indeed save time to some extent.

But that is relative to the test flight.

In actual operation, it is still affected by the complexity of the simulated system itself, as well as the operator's algorithms and theoretical foundation.

The leader’s schedule is well arranged, and he will only stay here for two days at most.

If Academician Chang himself were here, perhaps there would still be time to come up with a concrete result.

But let yourself come...

That's really a bit embarrassing.

Fortunately, Jiang Jianjun had a quick mind and quickly came up with an alternative plan.

So he nodded firmly:

"It may take some time to come to a specific quantitative conclusion, but if we just want to qualitatively verify the feasibility, it won't take too long..."

As expected, Qiao Chenqing immediately showed joy:

"Well, I'll stay in Gaojing for one more night so I can bring back more accurate information to Junwei!"

……

After sending Qiao Chenqing and his group away temporarily, He Haiqiang, the assistant who had been standing by without saying anything, came forward with a look on his face as if he had eaten a bitter gourd:

"Boss Jiang, a little more time like this could really help..."

Halfway through his speech, Jiang Jianjun interrupted him with a wave of his hand:

"It's just a feasibility test. Since Academician Chang has even given us the direction to solve the problem, we can't let them down..."

As he spoke, he picked up the piece of white paper with only one sentence written on it from the table:

"Xiao He, please remember this."

He Haiqiang was startled and quickly sat down next to him, spreading out the notebook under his arm on the table.

"We continue to use the transient conservation control equations that we are familiar with, but considering that this problem contains large-scale detached vortices and there are restrictions on wall conditions, we use the Reynolds average method in the boundary layer near the wall and use the turbulence model to simulate the small-scale pulsating motion therein. On the far wall, the scale parameter in the dissipation term of the turbulence model is replaced by the product of the grid scale and the solution of an ordinary differential equation..."

"The entire model uses a partitioned structured grid, which is divided into 22 zones in total. The area near the missile body uses an O-shaped structured grid, and the head and body each contain five zones..."

"..."

After determining the next work direction, the entire project team began to operate at an unprecedented high efficiency.

When Qiao Chenqing returned to Gaofei Group the next morning, in addition to Jiang Jianjun with bloodshot eyes, there appeared in front of him several pages of data distribution charts that smelled of ink and were obviously just printed out.

"The results are out yet?"

He quickly took two steps forward and came to the drawing boards with the results on them.

"That's right, Chief."

Jiang Jianjun perked up and pointed to the first chart on the far left:

“您看，我们在弹舱前缘设置了五条高36mm、宽10mm、长450mm的扰动装置，并分别测试了0°、15°和30°三个大小的后壁倾角，结果显示在马弹舱长深比为12、马赫数Ma=1.8的情况下，不仅弹舱外偏航力矩的最大值减小了12%-27%，而且弹仓内所有测点的总声压级也都出现了1.0-1.4dB不等的降低，相当于同时改善了舱外气流情况和舱内振动情况。”

"Although these two numbers are not enough to completely solve the problem, the current results are just the initial values ​​we selected based on experience. There is still a huge room for optimization in the future... More importantly, the leading edge disturbance device can serve as a structural reinforcement rib, which will hardly affect the effective volume of the bomb bay itself. When the bomb bay door is closed, it will not have a negative impact on the radar reflection area, so..."

Hearing this, Qiao Chenqing couldn't hold back his emotions for a moment, and directly took over the second half of the sentence:

"So, the same idea can be used directly in the weapons bay of stealth aircraft?"

"exactly."

Jiang Jianjun's face was no longer sleepy.

"We compared this design concept with the shallow-cavity bomb bay of the F22 fighter and the S37 verification aircraft, and found that the United States and Russia should also have adopted similar technical solutions, so it is not easy to see the clues from the appearance alone..."

"As for the working principle, we speculate that it is because when the airflow flows through the metal strip, a series of high-frequency vortices are generated. The frequency of these vortices is much higher than the frequency of the noise circuit itself, which can enhance the mixing of the airflow in the shear layer, destroy the large vortex structure and absorb the energy of the shear layer, thereby destroying the circuit that generates the noise to a certain extent..."

Qiao Chenqing naturally didn't quite understand the specific technical content.

But he didn't dwell on the details.

He just took a deep breath and scanned the drawing boards in front of him again:

"It seems that Academician Chang's piece of paper really solved a big problem..."