[CFD] Meshing Guide for Pipes and Ducts (O-grid, hexcore, polyhedra)

Рет қаралды 17,770

Күн бұрын

An overview of different methods for meshing a 90 degree pipe bend for modern CFD codes:
Timestamps
0:00 Introduction
2:32 Tetrahedral only
6:56 Tetrahedral with layers
8:58 Inefficient volume fill
15:11 Hexcore volume fill
16:19 Polyhedral volume fill
17:39 Numerical diffusion
31:45 Tetrahedral fill (revisit)
32:45 Hexcore (revisit)
34:23 Single block
37:31 Standard O-grid
40:11 Curved O-grid
42:41 Bell-shaped O-grid
46:24 Mapped approach
52:57 Outro
#computationalfluiddynamics #ansa #cfd
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Disclaimer
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The methods, algorithms, equations, formulae, diagrams and explanations in this talk are for educational and demonstrative purposes only. They should never be used to analyse, design, accredit or validate real scientific / engineering / mathematical structures and flow systems. For such applications, appropriate trained, qualified and accredited (SQEP) engineers / scientists should be consulted along with the appropriate documentation, procedures and engineering standards. Furthermore, the information contained within this talk has not been verified, peer reviewed or checked in any way and is likely to contain several errors. It is therefore not appropriate to use this talk itself (or any of the algorithms, equations, formulae, diagrams and explanations contained within this talk) as an academic or technical reference. The reader should consult the original references and follow the verification and validation processes adopted by your company / institution when carrying out engineering calculations and analyses. Fluid Mechanics 101 and Dr. Aidan Wimshurst are not accountable or liable in any form for the use or misuse of the information contained in this talk beyond the specific educational and demonstrative purposes for which it was intended.

Пікірлер: 60

@kauffman_47 Жыл бұрын

Wow, this video has been a game-changer for my doctoral thesis research! 🌟 Your clarity and depth of knowledge on the topic are truly impressive. Thanks so much for creating and sharing this invaluable resource with us. Your work is truly inspiring and a valuable contribution to the academic community. Keep up the great work! 👏👍

@TheManolis1984 Жыл бұрын

Fantastic video on meshing. I have used polyhedral meshing for complex geometries (compressors, fan impellers) and I have to say I am blown away with the amount of time I can save per simulation, without sacrificing solution accuracy. I also use hexahedral meshing a lot and I very rarely use tetrahedrals anymore.

@fluidmechanics101 Жыл бұрын

It is just so satisfying to get a solution with the same accuracy but with a smaller mesh. Faster solution time, faster post processing, smaller files. Everything is just so much easier 😊 People often focus on the smaller matrices and faster solution time, but in practice you set off a simulation and then forget about it. It is the faster loading times, faster post processing and smaller file sizes that really make life better!

@sandipgewali641 Жыл бұрын

Loved it !! Need more meshing videos. This is neither taught nor found in an understandable way in textbooks.

@laidmessaoudi5335 Жыл бұрын

All the questions are answered in this amazing presentation. Thanks a lot for sharing your experience.

@darshangohel6873 Жыл бұрын

Amazing work, professor Aidan ❤️

@simonrammel3464 5 ай бұрын

one of the BEST videos in the field, congrats - Simon!

@tomofford9914 Жыл бұрын

Thanks Dr. A, your explanation of numerical diffusion was very enlightening. I've only seen this discussed before in the context of discretisation schemes and hadn't appreciated the importance of mesh alignment. I like both this style of video and the "first principles" style, they complement each other nicely.

@fluidmechanics101 Жыл бұрын

Yep, people often forget the mesh!

@sakurasuper Жыл бұрын

thanks a lot for this meshing guide, it is really nice to have a complete overview of the different meshing approaches available. Meshing is a key element in cfd but it is often overlooked, because it can be tedious a time consuming. i would surely appreciate more contents on Ansa, like a step by step guide on how to achieve high quality mesh with optimal volume filling on a more complex/real geometry. Ansa seems really powerful but i am having trouble getting out of my meshing habits (i.e. triangular surface mesh > prism layers > tetra filling) !

@edwardagim7235 3 ай бұрын

best video on meshing I have seen. Thank you so much!

@lfmantilla Жыл бұрын

Thank you so much for sharing this type of content

@eig_himanshu Жыл бұрын

Sir you are doing a great work!!

@romanskrasek2939 Жыл бұрын

Thank you for your explanation of the mesh diffusivity, now it seems clear for me. I am also using ANSA & META software in a daily basis. Regarding the topics which are in my wishlist, I want to ask you for the topics about FAN boundary conditions (OF, Fluent/StarCCM) and fans in cfd in general and then about the NVD ant TVD diagrams? These topics are not solved in YT and you are the man, who can do it (as always) as best🙂🌬

@delvonei Жыл бұрын

Thank you very much indeed. Great and usefull video!! I loved it.

@chathukawickramasinghe5532 Ай бұрын

Thank you, the video is very clear!

@francootaola9172 Жыл бұрын

Yes yes yeeees more videeeeos about meshing 😍😍😍 still waiting for a video in cut blocking 😁 (this would also be an awesome udemy cours!)as always great video man!

@tmgi9123 Жыл бұрын

Excellent 🎉

@EngrAly-qr6yg Жыл бұрын

Excellent

@samisri7188 Жыл бұрын

More! More! More! More! More!

@MusAbssiAbssi Жыл бұрын

A very nice video thank you

@yavuzaks1348 Жыл бұрын

Best of the bests

@redhotminipepper1 Жыл бұрын

Im afraid the audio is distorted Aidan.

@nathansanchez3035 Жыл бұрын

^^ :(

@fluidmechanics101 Жыл бұрын

How strange, I wonder why it distorted the audio. I will look into this and try and fix it. Sorry everyone!

@Toni999985 Жыл бұрын

Great video Aidan! Could you please make a video on solution initialisation?

@Owningmovies Жыл бұрын

Thank you very much! If I may ask, could you expand on why tetrahedral cells do not give better resolution? The way I picture it in my head is that if I have n points of information in a volume, greater n means greater resolution.

@yashkaushik4992 7 күн бұрын

I have a very important question that I have trying to find the answer to in your meshing playlist. From what I see, the boundary layers are always hexahedral cells and its the volume cells that we chose whether to keep tet,hex,poly. My professor wants me to do the boundary layers also as polyhedral cells. This option is normally not there in OpenFOAM or Alter., is there a possiblity to use poly cells for boundary layers too. I know that when we double the cell size with each layer for square cell, one face of the bigger cell accomodates 4small faces so that is indeed polyhedral, but I am talking about the weirdly shaped poly cells.

@Leo-cg4fe 2 ай бұрын

hi ! thank you very much for this video, it is very well explained ! what do you think about a radial mapping with a growth rate instead ? if I'm right the issue with numerical diffusion is non transverse to the flow meshing, radial meshing with prisms would not be an issue.

@deepeshmeena20 Жыл бұрын

Please make a video on advective and periodic boundary condition

@ammarlaichi8474 Жыл бұрын

Hello Dr, what is the mesh suitable for simple circular pipe and circular pipe with circular corrugated in the inner wall?

@kanekanekun Жыл бұрын

Great content! Does anyone have recommendations of free meshing softwares?

@ahmad.s94 Жыл бұрын

Thank you so much ❤ Please, could you make a special video on one of the topics: Phase change models, The porous media model, Combustion models

@fluidmechanics101 Жыл бұрын

... all the difficult topics!

@ahmad.s94 Жыл бұрын

@@fluidmechanics101 These are really difficult topics If you have enough time to talk about some of these topics, it will be very useful Thank you Dr. Aidan for all your efforts

@ChuYanWong-ob5xj Жыл бұрын

Thanks Dr. Aidan for this useful video on this topic. Could you please share some experience on the sector meshing? Normally, what do we need to consider for meshing a sector of a pipe, I have found that the first cell at the bottom near the sharp corner, the quality is particularly bad. Thanks in advanced

@fluidmechanics101 Жыл бұрын

If you are using ICEM CFD (block structured) you can use a 'Y block'. If you are using an unstructured mesh, you can fit a triangle into the corner. The key is to not make your sector too small. I would try and keep your sector angle at least 15 degrees. If your sector is any smaller, it is better to just use a 2D axisymmetric model.

@uditsharmaification Жыл бұрын

Absolutely incredible video, every concept was perfectly explained! I have one question however, why do we see (mathematically) numerical diffusion when the mesh is tilted/skewed? I can understand it intrinsically, but is there a mathematical explanation as well?

@fluidmechanics101 Жыл бұрын

The mathematical explanation is in the book by Patankar 'Numerical Heat Transfer and Fluid Flow'

@selimhandogan6693 Жыл бұрын

Is there any chance we can get a video about gap modelling?

@mahdikh1822 Жыл бұрын

Thank you for the very useful information in this video. Using O-grid meshing, it seems that the elements near the wall have high aspect ratio. Does it harm the accuracy of solution, especially when you have turbulence anisotropy?

@fluidmechanics101 Жыл бұрын

That depends on your Turbulence model 🙂 For LES it definitely will, for RANS less so (but you can always do a mesh refinement study to check)

@edwardagim7235 3 ай бұрын

Do you have same video using ansys design modeler or space claim?

@felipeescalona4694 6 ай бұрын

HI, THESE VIDEOS ARE HELPING ME A LOT TO DO CFD ANALYSIS, AND MANY CONCEPTS THAT SUPPORT THE THEORY ARE VERY USEFUL IN THE DIFFERENT APPLICATIONS. I WOULD LIKE TO HAVE THE NAMES OF BOOKS THAT I CAN REFERENCE TO CITE THEM IN A THESIS PAPER.

@fluidmechanics101 6 ай бұрын

You can cite this video 😎

@praneshdewangan Жыл бұрын

Great one again, Aiden! i have a question about the number of inflation layers for internal flows. I watched your video about inflation layers and it clearly explains the method but for a fully developed internal flow, the boundary layer meets up in the middle of the pipe, in that case how many inflation layers should we consider? i am sure we should not take the pipe radius as yt. It would be great if you can clarify this. Thanks!

@fluidmechanics101 Жыл бұрын

Great question. Normally for pipe flow we would look to try and get a smooth transition between the edge of the layers and the mesh in the core. This often results in the inflation layer thickness being ~ 20% of the pipe diameter. You are of course correct. Once the flow is fully developed, the boundary layer fills the entire pipe. We are just using the layers to try and increase the resolution of the near wall region, where the gradients are strongest

@praneshdewangan Жыл бұрын

@@fluidmechanics101 Awesome. Thanks man!

@alaaeddinelhemmali1370 Жыл бұрын

I wich if you do a complete comutional fluid course with codes for turbulence, I will buy it with what ever price

@fluidmechanics101 Жыл бұрын

That sounds like a big undertaking! Maybe one day if I have the time 😅 for now, the SIMPLE algorithm course is pretty extensive and can get you most of the way there (it doesn't have a turbulence model in it yet)

@jan-henrikrieger4661 Жыл бұрын

Very informative video, but I have one more question: What type of mesh should one choose when the diameter of the pipe varies along its length and also when the cross-section is not an ideal circle, but rather a jagged and wavy shape? Or can the presented meshes also be used for that purpose?

@fluidmechanics101 Жыл бұрын

These methods should still work. You might need to try them out and check the cell quality / distribution of cells. It is hard to say ahead of time, but I suspect that they will all work (the block structured mesh may struggle and have worse quality cells in the core region, but I suspect the near wall region should be fine)

@jan-henrikrieger4661 Жыл бұрын

@@fluidmechanics101 Thank you!

@sandipgewali641 Жыл бұрын

Intro and Outro parts' audio seem robotic. Might need to address this issue in future videos.