Chapter 932: Isn’t it? It’s really a steal?
Although there are still some things that they don’t understand, now that Chang Haonan, as the general manager, has made a decision, what will Wei Yongming and Song Jingming do next. Naturally, the original plan will be implemented.
After sending the two people away, the former sat back at his desk and stared at the third chapter of the paper on the screen for a long time——
In fact, so far, the computational divergence problem caused by high computational weights has not been solved, and there is not even a widely recognized cause.
Chang Haonan also realized the existence of this problem through a lot of practice in the past few years.
But when he was summarizing the problem to the second point, a light suddenly flashed in his mind.
The development of the stress field is mainly affected by the convection terms and deformation terms, and evolves rapidly in the form of exponential growth. However, the traditional numerical discretization format based on polynomial interpolation cannot accurately capture this exponential growth change pattern. This prevents the contribution of the convection term and the deformation term of the constitutive equation to the stress evolution from reaching a balance, resulting in calculation divergence.
Therefore, theoretically speaking, as long as the exponential growth rate of stress is slowed down in the area of large stress gradient change during the solution process of the finite volume method, the stability of the numerical calculation can be guaranteed.
So, after another quarter of an hour of brainstorming, Chang Haonan stood up suddenly.
The headquarters of the Aerospace Power Group is a relatively simple administrative agency and does not have research functions.
Therefore, even if you have an idea, you can't get results just by sitting in front of the computer in the office.
He first picked up the phone and contacted Zhu Yadan who was waiting on the first floor.
Then I changed my clothes and went downstairs, preparing to take the bus to the new location of the Torch Laboratory that has been completed.
There is a supercomputer there that is better than the Beijing Airlines Computing Center, which is enough for Chang Haonan to test whether the idea he just had is correct.
In fact, this work was almost entirely out of Chang Haonan's interest.
Due to the different theoretical principles and technical routes adopted by TORCMultiphysics software, it does not face the problem of high calculation weights.
But as a scholar who studies numerical calculations and regards solving N-S equation problems as a long-term goal, Chang Haonan is not particularly utilitarian in his research in this field.
After all, many seemingly earth-shattering achievements only originated from a seemingly useless curiosity.
After arriving at the laboratory, he dived into the computing center located underground in Building 2...
In the computer room, Wang Jie and Tan Haiyang were immersed in front of the computer, working on the Falcon The design of the engine nacelle of Project Z is optimized.
At this time, there was a sudden noise at the door.
The two raised their heads and saw their mentor hurriedly pushing in the door.
"?"
Looking at the sudden appearance of Chang Haonan, Qin Haiyang, who was not very familiar with the situation of the research team, naturally thought that he was coming to check the post.
So, he stood up directly, took out a work log from his schoolbag, sat upright, and prepared to report on the progress of his work.
But Wang Jie, who has been studying for a Ph.D. in Torch Lab for one year, knows very well that Chang Haonan basically does not engage in such formalistic work inspections.
Many tutors are keen on this because they often ask students to do research areas that they do not know much about. Only through regular reports can they keep track of the progress of the project.
And here...
Although the business scope of Torch Laboratory is wider than that of most research groups, every research direction must be familiar to the teachers themselves.
Especially for Chang Haonan, he basically only needs to take a look at the calculation program and calculation results, and simply ask a few questions to determine the current situation of the project with certainty.
Wang Jie already had a deep understanding of this when he was in Shanghai.
Therefore, he first patted Tan Haiyang's shoulder to signal the latter to relax. At the same time, he took two steps forward and briefly explained the work they were currently doing.
Chang Haonan had no idea of checking his work, and Wang Jie's work efficiency and attitude were very reassuring, so he simply nodded and sat in front of another computer terminal next to the computer room. , prepare to conduct your own research.
However, while waiting for the computer to turn on, he accidentally glanced at the screen next to him.
“Eh?”
It doesn't matter if you don't look at it, this look really attracted his attention:
"Are you... doing a flow field simulation of the engine nacelle?"
Logically speaking, the optimization of the aerodynamic shape of the aircraft is not yet meticulous enough to require digging into design details such as the engine nacelle.
So, this work should be a relatively simple structural optimization problem.
But it is obvious that Wang Jie and Tan Haiyang are not satisfied with this.
"That's right."
Wang Jie scratched his head and replied:
"We have carefully looked at the overall design plan of the Falcon Z project during this period and found that no matter how Optimizing the structure of the engine nacelle, especially the weight, will have minimal impact on the performance of the entire aircraft."
Chang Haonanxin said that it is indeed minimal, otherwise I would not dare to take it over for you two to practice on...
Of course, these words must not be spoken, so on the surface he still listened carefully.
"So, we were thinking, in addition to the structure, whether we can make some optimizations in other places."
"For example, aerodynamic resistance?"
Chang Haonan looked at it as completed. With the high-precision meshing of the nacelle model, Wang Jie has been given a higher evaluation in his heart.
However, the latter shook his head: "I did think about starting from the drag reduction level at the beginning. However, the tail-slung engine layout has inherent disadvantages in terms of drag, and the optimization range is really not large. It still affects the performance of the whole machine. It doesn’t help much. ”
"So in the end, we decided to learn from your previous ideas and use the calculation form of flow field combined with sound field to optimize the noise level in the cabin, especially in the rear of the cabin, by improving the internal structure of the engine nacelle."
It has to be said that although Wang Jie is only in his second year of Ph.D., he is indeed capable of taking charge of his own work.
It is not just a matter of ability, but also of subjective initiative.
At this time, the computer in front of Chang Haonan had also entered the supercomputing system, so he stopped asking for other details and devoted himself wholeheartedly to his work...
< br>……
The week passed quickly.
Chang Haonan’s research can be regarded as beginning to show signs.
He has found a constitutive equation that does not involve diffusion terms, and based on it has achieved convergence processing for convection terms and deformation terms.
It can be said that there is only one step left to solve the problem that is not faced by the Torch Group.
But Chang Haonan's doubts did not ease.
On the contrary, it became thicker.
You know, he used many special methods in solving this problem.
For example, from a calculation log whose result is divergence, use a data dimensionality reduction algorithm to extract useful data, and then iterate based on this to optimize the form of the constitutive equation.
As far as theoretical research is concerned, this is naked heresy and violent cheating.
It is almost equivalent to doing the multiple-choice geometry questions in the college entrance examination. Others are deriving step by step, but you directly use the ruler to measure.
However!
It is not that Chang Haonan is biased against Professor Anthony Jameson.
But besides him, there is probably no other person in the world who can master this method.
Then the question comes.
How did COMSOL solve this problem?
Could it be that Professor Jameson thought of some calculation method that was so clever that even Chang Haonan himself didn't discover it?
Or is it because the former is simply lucky and achieves the same effect as high-order data dimensionality reduction through blind guessing?
It doesn’t seem very reasonable...
But I can’t think of any other possibilities.
In short, Chang Haonan is increasingly looking forward to the day when the new version of COMSOL Multiphysics will be officially released.
However, plans cannot keep up with changes.
Before the release of a new product by a friend, something unexpected happened, interrupting Chang Haonan's work schedule...
The trouble came from the Hudong Factory.
On a Friday afternoon when it was raining heavily, Lei Zhixing suddenly took the train from Shanghai to Beijing overnight.
"Mr. Chang, there is an emergency."
Lei Zhixing took off his wet poncho and placed it outside the door, then shook off the water drops on his body before walking into Chang Haonan's office.
While talking, the former placed a sealed file bag on his desk.
Different from the seal they affixed themselves last time, this time the seal had a large seal, indicating that it contained serious factory documents.
While Chang Haonan was unpacking, Lei Zhixing briefly introduced the situation:
“After Samsung Offshore took away our order for 8 LNG ships, The action was very rapid, and the specific technical plan was finalized not long ago.”
"Then, we obtained the design drafts used by Koreans to bid through public channels."
When he said this, Chang Haonan had already taken out the contents of the portfolio.
It is a design drawing.
Or strictly speaking, it is a design plan.
It’s just that a lot of the content has been blacked out, leaving only the design drawing relatively complete.
But that's enough.
Because almost at a glance, Chang Haonan saw a set of structures around the cargo tank that he was very familiar with...
"I'll go..."
He was so shocked that his eyes almost popped out of his head:
“Isn’t this our BOG reliquefaction system?”
"You really dare to steal?"
(End of Chapter)