The Military-industrial Scientific Research System of the Academic Master Chapter 40

Chapter 40 Listen well!

Chang Haonan's presentation at this group meeting was originally mainly for graduate students in his own research group.

Even in Du Yishan's research team, not all of them are people like Yao Mengna or Fang Zhen. Most people have a relatively poor foundation in this area.

If we start directly talking about the simulation calculation process, for these people, it is basically equivalent to just looking at the facts.

People often don't understand things that they don't understand at all.

At best, you can just sigh and say how awesome it is afterwards, and you won't really learn anything.

That's why he planned to start with the theoretical part at the beginning.

But just now when he saw many teachers sitting in the audience, Chang Haonan did feel shaken for a moment.

Will these well-established professors get bored of lengthy explanations of basic theories?

Would you like to show off your skills in simulation first?

But the sentence Du Yishan just said mentioned two very crucial words:

Audit.

No matter how many people are sitting below, except for members of the same group, they are all listening.

This made him finally decide to continue with the original plan.

"We know that the force of a fluid acting on an object can be recorded as a function of 7 independent variables, F=f (l, θ, ρ, U, μ, ω, c), where l represents a certain representation of the object Length, as the characteristic length studied, θ represents..."

“After dimensional analysis, the force F on geometrically similar objects of the same type can be recorded as..."

“Let's discuss the dimensionless parameters appearing in the above formula in turn…”

At the beginning, Chang Haonan was indeed a little nervous.

But as the explanation continued, he quickly entered the state, and the chalk in his hand quickly wrote down one calculation after another on the blackboard.

Even people with relatively weak theoretical foundation can form a complete cognitive system for computational fluid dynamics simulation as long as they follow his ideas.

This is the power of knowledge given by the system.

In the last life, Chang Haonan was certainly very familiar with the application of computational fluid dynamics.

But when it comes to these theories, they can only be regarded as understanding at best.

After being reborn and receiving system buffs, this theoretical knowledge seemed to be engraved in his mind.

Chang Haonan actually felt that this basic theory was of little use, and it did not delay its application anyway.

But when the projects to be done later became more and more complex, he realized that this view was so wrong!

If you don't master the basic principles, you will always be following in the footsteps of others.

In fact, this cannot be said to be Chang Haonan's problem alone.

The period from the late 1980s to the early 1990s was the period when the aviation industry was most impacted by new knowledge.

A large number of theories and technologies that had not been exposed before poured into the country in a very short period of time, and they came from both the Soviet Union/Russia and the West.

Most of the time, the professors giving lectures on stage and the students listening in the audience are still in the learning process.

Hence, the college students of his generation, except for some truly gifted and talented people, have learned a bit... extensive but not sophisticated.

That's why Chang Haonan chose such a more transparent way of speaking. On the other side, Tang Lintian, who was listening below, had realized that there was something wrong with his judgment just now.

Although I haven't talked about the specific application part yet, such solid theoretical ability is definitely not something that a novice who needs to report learning progress in a group meeting can possess.

At this time, what Chang Haonan talked about finally entered the numerical simulation part.

"The direct numerical simulation method is to directly solve and calculate the N-S equation numerically. This method does not require approximate processing of turbulent flow, so its calculation results are more accurate. However, in most cases, this solution method is too computationally intensive. Huge, completely unrealistic given current computer capabilities.”

“For indirect numerical simulation methods, there are two main branches, namely the Reynolds average method and the large eddy simulation method…”

"The turbulent kinetic energy and dissipation rate equations of the RNGk-ω model of the Reynolds average method are very similar to the standard k-ω model. By integrating the previous equation 47, the impact of the effective Reynolds number (vortex scale) on turbulent transport can be accurately understood , which aids in the simulation of low Reynolds number and near-wall flow problems..."

Unconsciously, Chang Haonan had filled the four huge blackboards in front of him with writing.

Tang Lintian is deeply immersed in simulation. He also knows all the things Chang Haonan talks about, so he can devote some energy to paying attention to the status of other people around him.

Comparing to the basic physics content just now, even some teachers do not understand the theoretical part about simulation thoroughly in this part, so many people have already opened their notebooks and started taking notes.

As for the graduate students who were brought here, let alone them.

They are all continuing their studies after graduating from a bachelor's degree. How could they not realize that the computer age has arrived?

However, after all, there are only a few people who can rely entirely on self-taught.

Most people just hang around in front of the gate of this field without being able to enter, or they reluctantly get in but don't get the point.

In this case, a systematic theoretical explanation almost from scratch is nothing less than a guiding light for these people.

At this time, almost an hour and a half had passed since Chang Haonan started his lecture, but most people in the classroom still maintained their rapt attention.

For Tang Lintian, this was even more surprising than the content of the story itself.

As a professor who often teaches students, he knows very well where the limits of the classroom are.

A class lasts 45 minutes, and most people can only concentrate for 30-35 minutes. After that, even good students will be more or less distracted.

But in the current classroom, 90 minutes have passed, and this has not happened at all.

Tang Lintian also opened his notebook.

However, what he recorded was not the knowledge points taught by Chang Haonan, but a recollection of the latter's teaching methods from the beginning to the present.

About ten minutes later, looking at the contents of the notebook, he shook his head with some self-deprecation.

Just now I just listened to the lecture and I didn't feel anything. Now after I listed out the other person's ideas, I realized that being able to explain complex knowledge in a simple and profound way depends entirely on the other person's profound theoretical skills.

Even if he wants to turn these things into lesson plans, it will take a lot of effort.

However, Chang Haonan has been standing in front of the podium to explain without writing!

Thinking of this, Tang Lintian suddenly became curious.

How can a beginner make progress after listening to the entire explanation just now?

Coincidentally, sitting next to him was a boy who looked like a student and was wearing a shirt. At this time, the latter had already taken notes on about the fifth page.

So while Chang Haonan was erasing the blackboard, Tang Lintian stretched out his pen and lightly touched the other person's arm, preparing to ask him how he felt after hearing this.

Unexpectedly, the boy didn't even raise his head, he just shook his arm and said in a very impatient tone:

“Don't move and listen carefully!”

(End of this chapter)

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