After Shen Yiyi served tea to the two guests, he poured himself a glass of water and sat down at the table. She is a person who believes in drinking water aesthetics, so she usually pays attention to drinking more water. Drinking water can not only detoxify but also keep the skin tender and elastic, and can delay aging, so water is the best drink. This is a fact that has been publicly discussed in nutrition in later generations, and Shen Yiyi naturally follows it correctly.

Without her opening, Xiao Yizhan first took out a piece of paper, which was also the formulas of Shen Yiyi that his grandson Luo Yu had hand-copied before. The old man has endured it for so many days, and the question in his heart has never had a chance to be raised. Today finally came to the house of the initiator, and of course he was anxious to ask this question clearly and clearly.

"Classmate Shen Yiyi, you gave Luo Yu these formulas last time, right?"

Shen Yiyi glanced at the paper and nodded: "Yes, it's these formulas." You must have checked a lot of data in the past few days, right? Is there anything special? ”

Xiao Yizhan shook his head: "There is nothing special. We did calculate your formula, and based on the results, we selected the airfoils for these wings. But I want to ask you, why do you think that the result of your formula calculation is correct? These formulas are not provided in any textbook, so how do you prove that they are correct? ”

Shen Yiyi understood, looking at the appearance of this old man, he had doubts about the formula he gave. However, she doesn't think that the old man really has no confidence in the formula he gave. On the contrary, the fact that the old man was able to visit him in person today just shows that the old man has discovered the value of these formulas. And these formulas must have meant great things to him.

It is important to know that the current electronic computer technology is still very immature. The computing power of electronic computers currently available in China. THE COMPUTING LEVEL OF A WORKSTATION IS NOT AS GOOD AS THAT OF A MOBILE PHONE OR IPAD IN LATER GENERATIONS, SO IT IS NECESSARY TO USE NUMERICAL CALCULATIONS TO OBTAIN MORE ACCURATE NUMERICAL SOLUTIONS AS IN LATER GENERATIONS. In this day and age, the difficulty is not ordinary. Nowadays, the design of aircraft involves fluid mechanics, which mainly relies on empirical formulas, and also relies heavily on the wind test of the prototype model. As far as she can remember, in the 80s, when the country's scientific research funds were very tight, it also invested in Sichuan to establish a wind tunnel test device that was the largest in Asia at that time. Of course, even in later generations, even with high-performance supercomputers. There are also relatively mature computational fluid dynamics calculation software, and wind tunnel testing is still a very important research method. Because the principle of all human science is to explain natural phenomena and approximate the laws of nature, not the other way around. Therefore, some calculation software upgrades or patches are often specifically designed to solve the problem of deviation between the calculation results and the test results. Once there is a discrepancy between the calculation results and the test results, people always revise the calculation results after confirming that the test process is correct. It can be seen that the priority of wind tunnel experiments is always higher than that of the computational model.

The problem is that the lead time for wind tunnel testing is quite long. Problems in the production of models of blowing tunnels, installation of sensors, and placement of wires. The optimization of the flow field, etc., each of which requires time and economic costs. These costs exist, which is why engineers have developed a large number of virtual design processes that take place on computers. By simulating the test time by numerical calculations, the associated costs and time can be greatly saved. Achieve similar accuracy. Therefore, virtual design is an efficiency multiplier of aircraft design.

If Shen Yiyi was to specialize in aircraft design in her later life, then she would be very proficient in all aspects of virtual design. The proficiency in operating the software is also very proficient. But her return to 1994 was of little use. Because there was no computer in this era that could reach the level of a stand-alone workstation in later generations. At the same time, there is no such thing as a powerful fluid calculation software that can be used by everyone in this era. So. Such a computer-savvy talent is not able to work at all in this era. But Shen Yiyi is just a person who is opportunistic in order to mix her master's degree and her advanced engineering technology certificate. In order to make her paper public, she embodies new ideas. Deliberately through a large number of calculations by the calculation software, some test test formulas are reversed, but it seems that they are naturally prepared for this crossing. Comparing each calculation process on the computer to a wind tunnel test, she just took these experimental data, or calculation data, to form a new formula. Such a thing, even the Soviets, who are the most adept at summarizing these formulas, would not have had such conditions in the first place. Therefore, after returning to this era, especially after deciding to carry out this project, Shen Yiyi is really glad that his original unintentional willow insertion can now be regarded as a bright flower.

Regarding Old Man Xiao's question, Shen Yiyi was not afraid to answer. She smiled slightly at the time and asked the old man: "Old Xiao, if I say that these formulas are derived by me personally, do you believe it?" ”

"What? That's impossible! Xiao Yizhan was shocked by Shen Yiyi's bold remarks at that time, and immediately denied this possibility. As soon as the words came out, the old man also felt that his tone seemed to be a little stiff, softened his expression, and said to Shen Yiyi as pleasantly as possible: "Uh...... Shen Yiyi, you must have read these formulas from which book, right? If you don't tell us now, are you afraid that we will ask you for those books after we know the truth? You can rest assured, we only need to borrow it for a few days, and we will return it to you when we make a copy, and we will not requisition your book and not return it. "Old Man Xiao really thinks that Shen Yiyi is unwilling to tell the truth in order to protect his precious information book. He's an engineer himself, and he certainly understands how much engineering people care about an important reference book. With Shen Fei's status in the country, if the importance of Shen Yiyi's book is expressed to the relevant parties, then of course, according to the regulations, the state will directly ask Shen Yiyi to donate this book. He thought that Shen Yiyi would definitely not want to do that, so he took the initiative to explain to Shen Yiyi that they just wanted to copy a book, and the original book would still be returned to Shen Yiyi.

But Shen Yiyi shook his head and said, "Old Xiao, look. You still don't believe me. There is no such book. This formula is indeed my own derivation. ”

Old Man Xiao was a little unhappy. He thought to himself, I already told you this, and you still don't admit it. Little girl, you know the Tao of the Road, you don't know the Tao of the Road, this book has not been seen in the country, for the country. How important is it for the whole national defense? The female baby is narrow-minded and doesn't know the general situation. His good impression of Shen Yiyi just now immediately dropped a lot.

The old man's temper came up. You're welcome to speak.

"Okay, you said you pushed it yourself, how to push it, you talk about it. If you can't push it out, it means that you copied it from somewhere else, and you have to take out the book. ”

Luo Yu listened to it next to him, and his face began to have a fever. He looked at his grandfather and wondered why he started to play a scoundrel today. They really copied that book, so why should they show it to you? Neither is this book yours. Isn't it just that there are several formulas in the book, and if you don't give it, you won't give it. Why did my grandfather become a bandit, and he had to rob it openly. He was still young and did not understand the eagerness of Mr. Xiao to move forward quickly with a key aircraft project. If Mr. Xiao can get more formulas with these high-precision, then the air superiority fighter project in his hand will definitely be able to complete the technical design as soon as possible and start the manufacture of the prototype. The old gentleman is also too eager, so he is a little out of shape today.

Shen Yiyi can fully understand the old gentleman's mood. Because she knows the truth, in the past few years, several important projects of the Air Force have been carried out intensively. Therefore, according to her understanding, she is a famous person in the domestic aviation industry or a titan. Xiao Yizhan will see how important these formulas are, and also how important the origin of these formulas is. To be honest, if I had such a book in my hand, I would have offered it with both hands a long time ago. As a son and daughter of China. Who does not hope that the country will be rich and strong, and who does not hope that their country will be strong in the military. As an engineering woman, she hopes to equip her army with more advanced combat vehicles. But the problem is that I really don't have it in my hands.

Shen Yiyi said to Xiao Yizhan very sincerely: "Xiao Lao. In this way, I will sacrifice ugliness. I'll give you a formula in front of your old one, and you'll see. He said. I found a piece of paper, took a pen, and started to deduce directly on the table to the two people. When she was writing her dissertation, in order to make her forged test data have a reasonable source, she specialized in how to derive new formulas from some known empirical formulas, and she still put in some hard work in this regard, and she also cited some rules of thumb to improve her derivation process by checking information or using her brain, so she is not stage frightened at all in front of outsiders. So what Luo Yu and Xiao Yizhan saw was that this little girl was really in front of them, starting from an original formula, and deducing the whole process of getting a new formula that amazed them step by step.

"Old Xiao, you see, this formula is a formula that we all know, and I remember that there is a ...... in the fluid mechanics book This is the Zhukovsky transform, and after the transformation we can get this ...... A simplified assumption is used here...... This is a simplification in the case of a small Reynolds number, so this item can be discarded...... And this, if you are in the high-speed range, you must add this sticky item...... This is the equivalent infinitesimal ......"

As if it was magic, through Shen Yiyi's item-by-item explanation, Luo Yu seemed to understand it, because he actually had a lot of mathematical tools that he hadn't learned at all; But Xiao Yizhan sounded like an initiation. That's right, it's right to deduce in this direction, why didn't I think of it before? The ideological shock brought by Shen Yiyi's derivation to Xiao Lao made his gaze change when he looked at the girl in front of him. Before, he thought that Shen Yiyi didn't tell the truth in order not to dedicate books, but now he can't help but think, could it be that I really met a genius? (To be continued......)

PS: Finally finished today's meal. The two of you are still satisfied, right? > this, a novel is a novel after all, and you don't need to delve into who Xiao Lao is, he is one of the thousands of senior intellectuals who have contributed to China's scientific and technological and industrial progress. As for whether there is such an empirical formula, theoretically there is. Of course, you can also think of the elements of fiction as pure fiction. Look at my code words are so diligent today, everyone will reward me with subscriptions and collections.