202: Falling into a misunderstanding

However, in 1996, studying abroad was not solely dependent on financial means.

Tang Ziwei hoped to obtain recommendation letters by making friends like Old Wei, so that she would have a chance to study abroad in the future.

She didn't understand why some people were hostile towards the United States.

Nevertheless, she would still nod appropriately during conversations to show support.

She believed that as long as she could achieve excellent grades in the aircraft design course, she would pave the way for her future.

That evening, due to the poor safety conditions in the city, they ended their dinner early.

Zhao Zhide returned to his rented accommodation, while the other three went back to the academy together.

After returning to the dormitory, Xu Ning recalled several roommates who were keen on playing cards, gathering almost every night for games unless final exams were approaching.

Instead of returning directly to the dormitory, Xu Ning walked towards the public phone booth on the corner and dialed his home number.

When he heard his parents' familiar voices, tears almost welled up in his eyes.

To avoid worrying his parents, he tried his best to control his emotions, chatted briefly, and then hung up using the excuse that he needed to go back and rest.

After adjusting his mood for a while, Xu Ning decided to go to the library because it had the latest newspapers and magazines.

Soon, Xu Ning sat on a bench, quickly browsing the newspaper in his hand.

He didn't need to remember all the details, just get a general understanding of recent major events.

The news mentioned that the impact of a major event from the beginning of the year was still ongoing, and there were also several shooting incidents that occurred last month.

In addition, news about the successful launch and docking of the last part of the Mir space station, the Priroda module, also made headlines.

Just as he was engrossed in reading, a familiar voice came from behind him: "Chang team member, are you so free today?"

Turning around, he saw Yao Meiling, the Junior Sister he had met in the computer room before.

"Well, I think besides studying, one should also care about world affairs," Xu Ning replied with a smile.

Noticing that the library was about to close, he quickly tidied up the newspapers and magazines on the table, put on his backpack, and left with Yao Meiling.

It was only a few steps from the newspaper and magazine section to the exit, but within this short distance, Yao Meiling stole several glances at Xu Ning.

It turned out that she had come to find materials about fluid dynamics simulation, as her research group had encountered a problem.

When she saw Xu Ning, she almost instinctively greeted him.

Yao Meiling pondered, perhaps this third-year Junior Brother could help.

But when she was about to speak, she hesitated.

The problem she encountered this time was much more complex than before, and her previous experience left her with lingering fears.

However, for the sake of the research group's project, she decided to temporarily put aside her concerns.

"Xu Ning, could I ask you a question about Computational Fluid Dynamics?" she asked tentatively.

Xu Ning calmly responded, "No problem, go ahead."

"We are studying an aeroelastic instability phenomenon involving large geometric deformation, occurring on a specific type of aircraft wing.

However, we encountered difficulties when using a method similar to last time to solve the N-S equations and Euler equations; not only was it slow, but the error was also very large," Yao Meiling explained.

"Wait a moment," Xu Ning interrupted her, "Which specific type of wing are you studying?"

Yao Meiling was momentarily speechless: "I just wanted to discuss the methodology..."

"Different types of wings, such as delta wings, swept wings, and high-aspect-ratio straight wings, have vastly different characteristics," Xu Ning said seriously, "If this is sensitive information, you don't have to disclose it."

"Don't worry, this is a public research project," Yao Meiling quickly clarified, "We are dealing with high-aspect-ratio straight wings, and we've also tried adjusting the Dewey-Hodges model, but the effect was not good."

"This situation is not uncommon," Xu Ning nodded, appearing confident, "For this type of wing, one of the most typical challenges is flutter.

Traditional CFD/CSD coupling technology is not suitable for solving such problems."

Since the advent of aircraft, wing flutter has always been a serious hidden danger.

It is caused by the dynamic interaction between aerodynamics, material elasticity, and inertia.

Yao Meiling looked at Xu Ning beside her in surprise, her mouth slightly open.

She had envisioned many possibilities, but never expected that she had deviated from the correct path from the very beginning.

What shocked her even more was that this obvious problem was easily pointed out by an undergraduate student, which completely overturned her perception of her own ability.

"Did I really study for nothing all these years?" A hint of self-doubt flashed in her heart.

At this point, Xu Ning continued to explain: "High-aspect-ratio wings are essentially beam structures, so we can use subsonic dipole lattice technology to estimate unsteady aerodynamic effects.

According to the linear assumption, acceleration potential dipoles are one of the key factors in solving such problems.

When we consider the wing vibrating harmonically, we can arrange a series of such dipoles on its surface, ensuring they meet specific vibration boundary conditions.

In this way, the pressure difference Δp can be calculated, but this method is only applicable to linear cases."

Noticing that Yao Meiling was deep in thought, Xu Ning stopped and asked, "Do you understand?"

Hearing his familiar questioning tone, Yao Meiling couldn't help but feel a surge of annoyance.

But she knew deeply that in the face of expertise, only admitting one's shortcomings was the right way.

"I understand," she replied, "If the dipole lattice method is used, does that mean using the msc.nastran software would be more suitable?"

As a doctoral student, Yao Meiling was not incompetent; she had just fallen into a misconception before.

Now that she had been reminded, she quickly grasped the key point and believed she had found the direction to solve the problem.

"Good thing my efforts weren't wasted," she thought silently.

Just as a hint of joy arose in Yao Meiling's heart, Xu Ning dealt her another blow: "The standard version of msc.nastran might not be ideal.

To achieve the best results, you might need to customize the program internally using the damp language, but this requires a specific understanding of your research background to provide further guidance."

After hearing this, Yao Meiling looked up at the bright moon in the night sky.

Although it was already the end of May, her mood was as complex as sung in a certain song.

Snowflakes gently fell, the cold wind howled, and the whole world seemed to be draped in silver.

At the same time, Old Wei and Tang Ziwei simply buried themselves in hard work at the library, finally calculating the key parameters in the first design plan.

After lunch, Xu Ning quickly finished his meal and rushed to the computer room with the calculation results and the four team members' IDs.

However, the progress was not as smooth as he had expected.

Although the upcoming work was not complicated for him.

But it was a significant challenge for the computers at that time, especially the design involving the inner surface of the intake duct, which had to be completed by the computer.

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