Chapter 1213 A Big Problem Solved with a Piece of Paper

There is only one main sentence written on such a large piece of paper. If you put it aside in normal times, it would be a bit meaningless.

After all, when doing things in the academic circle, the title, abstract, introduction, and text and conclusion citations should be complete, and the six elements should be complete, just like that.

Even people at the level of the founder of the industry generally do not break this rule.

But considering that the Haofei Group is currently struggling with the issue of the flow field characteristics of the bomb bay, this sentence can be regarded as a 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.

And Qiao Chenqing, who was next to him, had already understood the meaning of the sentence on the paper:

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

"Yes."

Although he was asking questions knowingly, it was the leader who spoke after all. Jiang Jianjun quickly stopped preparing to ask someone to do something and gave an affirmative answer.

Qiao Chenqing couldn't help but show a shocked expression.

Although he had heard 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 must know that the other party has not directly intervened in the modification of this Tu-160.

Now suddenly a letter was sent with the design parameters of the verification bomb, and it happened to meet the biggest trouble faced here?

The last time Qiao Chenqing heard about this kind of thing was when he was a child. The storyteller talked about the tips in "The Romance of the Three Kingdoms"...

"Then... how feasible is it?"

At this time, he couldn't care less about continuing to act like a leader and quickly asked.

Jiang Jianjun was stunned for a moment, and then replied helplessly:

"Chief, I just saw this letter a few minutes ago. How could I know right away..."

At this time, Qiao Chenqing also realized that he was a little anxious, so he prepared to add a few words to avoid putting too much pressure on the other party.

But before he could say anything, 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 structure of the bomb bay is no longer a typical cavity in terms of aerodynamics, and the problem will be solved naturally... Just rely on the inclination angle to change To achieve this effect, an angle of about 70° is required, which is equivalent to directly occupying half or more of the effective space in the weapon bay, and it is not feasible in engineering. "

"As for combining it with the leading edge spoiler..."

The latter showed a little shame on his face:

"It is indeed an idea that we have not tried before."

Qiao Chenqing naturally wouldn't criticize the other party for this kind of thing, and what's more, what he is most interested in now is not the issue itself.

"Comrade Jianjun, you have been working in the aviation industry system for a long time, so I would like to ask an additional question..."

He softened his tone slightly:

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

"What I mean is that although people are far away, they can still guide the specific work."

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

"The last time I worked on a project with Academician Chang was in 1997. At that time, we were going to use the H-6 to modify a water spray test machine to simulate icing... The task was not complicated, and Academician Chang didn't seem to have done it at the time. I have graduated, so I don’t have too deep feelings.”

"But according to Mr. Liang, who was transferred from Nanzheng after the merger, it seems that it is indeed not much different..."

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

Then, there was another silence.

In the end, it was Qiao Chenqing who took the lead to break the deadlock:

"Then the next step is to conduct flight tests again according to the ideas given by Academician Chang?"

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

"That's not true."

He shook his head:

"Even with the advice given by Academician Chang, we cannot directly take the risk of flying on the aircraft. We must first conduct numerical simulations and wind tunnel tests to at least verify the feasibility and safety of this solution."

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 abruptly, with a hint of curiosity in his eyes.

In his early years, when he was serving in the Air Force of the Beijing Military Region, he heard a report from the Aviation Industry Group, which mentioned the use of computer simulation technology to improve test flight accuracy and reduce unnecessary test flight time to some extent.

So some idea of ​​this:

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

Jiang Jianjun raised his eyes slightly and saw Qiao Chenqing's face full of expectation. He immediately guessed that the other party wanted to stay and see the results with his own eyes, and he suddenly smiled bitterly——

Numerical simulation does save time to some extent.

But that's relative to test flights.

Actual operation is still affected by the complexity of the simulated system itself, as well as the algorithm and theoretical skills of the operator.

The leader's itinerary has been arranged, and he will only stay here for two days at most.

If Academician Chang himself were here, it might still be time to come up with concrete results.

But let yourself do it...

That's really a bit embarrassing.

Fortunately, Jiang Jianjun had a quick mind and quickly thought of an alternative.

So he nodded firmly:

"I'm afraid it will take some time to reach specific quantitative conclusions, but if it is just a qualitative verification of feasibility, it really won't take too long..."

Sure enough, Qiao Chenqing immediately showed joy:

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

...

After sending Qiao Chenqing and his group away temporarily, He Haiqiang, the assistant who had been following him without saying anything, came forward with a bitter look on his face:

"Mr. Jiang, one more day can really help..."

He was interrupted by Jiang Jianjun halfway through his speech:

"It's just a feasibility verification. Since Academician Chang has even given the direction of the solution, we can't be too slow..."

He picked up the white paper with only one sentence on it from the table:

"Xiao He, take a note."

He Haiqiang was startled and quickly sat next to him, and spread 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 wall conditions, the Reynolds average method is used in the boundary layer near the wall, and the turbulence model is used to simulate the small-scale pulsating motion. 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 the body each contain five partitions..."

"..."

After determining the next work direction, the entire project team started 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 a few pages of data distribution charts that smelled of ink and were obviously printed out not long ago.

"The results are out?"

He hurriedly took two steps forward and came to the drawing boards with the results.

"That's right, Chief."

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

"You see, we set up five disturbance devices with a height of 3 and a length of 450mm on the leading edge of the bomb bay, and tested the three rear wall inclination angles of 0°, 15° and 30° respectively. The results show that when the Mach number Ma=1.8 and the length-to-depth ratio of the bomb bay is 12, not only the maximum value of the yaw moment outside the bomb bay is reduced by 12%-27%, but also the total sound pressure level of all measuring points in the bomb bay has also decreased by 1.0-1.4dB, which is equivalent to improving the airflow outside the cabin and the vibration inside the cabin at the same time."

"Although these two numbers are not enough to completely solve the problem, the current results are only 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 act as a structural reinforcement rib, which will hardly affect the effective volume of the bomb bay itself. When the bomb bay door is closed, the leading edge disturbance device can be used as a structural reinforcement rib, which will hardly affect the effective volume of the bomb bay itself. , 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 while, and directly took over the second half of the sentence:

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

"That's right."

Jiang Jianjun's face was no longer sleepy:

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

"Regarding the working principle, we speculate that it is because a series of high-frequency vortices are generated when the airflow flows through the metal strip. The frequency of these vortices is much greater 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 generated by the noise to a certain extent..."

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

But he didn't dwell on these details.

He just took a deep breath slowly, and his eyes swept across the drawing boards in front of him again:

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