[CFD] Porous Zones in CFD

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Fluid Mechanics 101

Fluid Mechanics 101

Күн бұрын

Пікірлер: 193
@tianxiaoxie6437
@tianxiaoxie6437 4 жыл бұрын
Thank you very much Doctor Aidan for your excelent explaination. But there might be a mistake about the definition of the "superficial velocity". I have read different explainations about the "superficial velocity" online, The superficial velocity ist defined as the volume flow rate divided by the cross area, which is, i think, the velocity "U", that you mentioned in your video. The "Us", which you called superficial velocity is maybe the physical velocity. In the the superficial velocity is equal to porosity times physical velosity, which means the superficial velocity is smaller than the physical velocity. But according to your definition the superficial velocity will be bigger than the physical velocity. maybe its just a mistake :)
@fluidmechanics101
@fluidmechanics101 4 жыл бұрын
Yes this is a mistake. I have pinned your comment so everyone can see 😊
@raheemnabi2989
@raheemnabi2989 Жыл бұрын
Mate, I’m a research engineer with a full-on doctorate in CFD and after all these years I still come back to your videos over any text book or technical paper if I need to recap or familiarise myself with some aspect in OpenFOAM or fluid dynamics in general. There are students out there paying over 10 grand for an engineering education that is 10 thousand times more shitty in quality and you’re providing all of this for free. You’re an absolute legend. Keep up the good work.
@fluidmechanics101
@fluidmechanics101 Жыл бұрын
Thank you, it means a lot 🙂
@shuangtu8067
@shuangtu8067 3 жыл бұрын
Excellent lecture! The unit of C1/t should be kg/(m^3-s) instead of kg/m^3.
@fluidmechanics101
@fluidmechanics101 3 жыл бұрын
Yes, well spotted 😅 thanks for the correction
@TheManolis1984
@TheManolis1984 4 жыл бұрын
Great video as always. Another resource with a lot of empirical C2 or K coefficients is the "Handbook of Hydraulic Resistance" by I. E. Idelchik If there are no manufacturer's data or you can't find a C2 or K coefficient in literature there is a 3rd way Run a virtual wind tunnel CFD simulation of a small portion of your grill/louver/heat exchanger etc for increasing face velocities and plot the pressure drop. You can then extract C2 or K with a polynomial fit as with the 2nd method you described.
@fluidmechanics101
@fluidmechanics101 4 жыл бұрын
Yes! Completely agree with all your points. Thanks Manolis
@danmorris9533
@danmorris9533 3 жыл бұрын
do you run this CFD sim assuming no porous zones?
@CFDER-zw8rz
@CFDER-zw8rz Жыл бұрын
@@danmorris9533 I think what @themanolis1984 meant was to make a small part of the material that you want to study as porous zone, as realistic as you can; meaning actually designing the geometry of the domain (as a realistic porous zone, not using porous zone option in your CFD simulation) and running the simulation to get the "pressure drop vs velocity" data, then use that data for simulation in larger scale using "porous zone" option in CFD code. One assumption for this approach I think is that the porous material is isotropic and homogeneous.
@anshumandas9710
@anshumandas9710 4 жыл бұрын
Thanks a lot, this video particularly helped me to get a an understanding of simulating flows through barrier.
@md.ridwanulhassanrafi6851
@md.ridwanulhassanrafi6851 3 ай бұрын
Explained it in a real easy way..thank you.
@naldofrasco1467
@naldofrasco1467 5 жыл бұрын
Thanks Aidan. Other applications are items like filters (gas or liquid) and exhaust baffles.
@fluidmechanics101
@fluidmechanics101 5 жыл бұрын
Yes!
@木瓜-h1b
@木瓜-h1b 3 жыл бұрын
Thank you ! I just search info about the porous region and i got ur video))))
@user-hs3dg8jy3t
@user-hs3dg8jy3t 3 жыл бұрын
GOAT fluid dynamics teacher
@sehr_nice
@sehr_nice Жыл бұрын
Great video, helped me a lot with my understanding! Good job!
@CallumSamuels
@CallumSamuels 3 жыл бұрын
Dude , your videos are brilliant! Thanks so much!
@harshakorlur1007
@harshakorlur1007 3 жыл бұрын
Excellent information. Thank you for the video.
@mahmutkaplan590
@mahmutkaplan590 4 жыл бұрын
Thank you. It is very clear and useful.
@mustafasahinturk9651
@mustafasahinturk9651 7 ай бұрын
Absolutely amazing channel!
@leechulmin5033
@leechulmin5033 4 жыл бұрын
This lecture is so helpful and so easy to follow thanks so much!
@parisa_moradi93
@parisa_moradi93 2 жыл бұрын
It was amazing thank you so much for perfect explanation. Have a good day
@naeemsadiq4656
@naeemsadiq4656 Жыл бұрын
Thanku so much sir. It is so interesting and informating. Please keep it up
@mitikuamanumesele3975
@mitikuamanumesele3975 3 жыл бұрын
thank you for your brief explanation endeed..your presentation has always been so helpfull.and detailed ...but, isnt the unit of (c1/t=kg/m3s)?
@fluidmechanics101
@fluidmechanics101 3 жыл бұрын
Hmmm I think I might have made a small typo here. Let me get back to you on this one
@rpapa
@rpapa 3 жыл бұрын
Thanks a lot !!!!! this video is very very very helpful!!!!!
@omidtutunchian3304
@omidtutunchian3304 3 жыл бұрын
your explanations is very useful and great. thank you so much
@abdelazizbammoune8976
@abdelazizbammoune8976 2 жыл бұрын
very important lesson .... thank you
@cronos864
@cronos864 Жыл бұрын
Great video as always. Thanks!
@ahamed68_CFD
@ahamed68_CFD 9 ай бұрын
Excellent explanation. I have a question about C1, what is the recommended value for it in the solid direction ?
@fluidmechanics101
@fluidmechanics101 9 ай бұрын
10 or 100 times the value in the fluid direction is normally fine. You just need the resistance to be higher than the fluid direction, so that the flow is encouraged to straighten and flow in the fluid direction. A small amount of flow in the solid direction is fine and makes convergence a lot easier
@romanskrasek2939
@romanskrasek2939 3 жыл бұрын
Dear Mr. Wimshurst, I appreciate your work, it's a big help for me. All your videos are very helpful. Can I have a question: are you planning to make a video about FAN boundary conditions (in OpenFoam etc.)? Thank you :-)
@ammarlaichi8474
@ammarlaichi8474 Жыл бұрын
Thank you Dr for this seance, I have questions: 1- in higher reynolds number what is the model suitable for pouros media Darcy or Darcy-Forchheimer? 2- How does the setup of pours media in ansys fluent?
@sayujs7118
@sayujs7118 5 жыл бұрын
I think the definition of superficial velocity is incorrect. It is a volume averaged velocity where averaging is done over the volume containing both fluid and solid. This velocity is basically the product of porosity times the intrinsic average velocity where now the averaging is done over the fluid volume only. The velocity you mentioned in the schematic is the pore velocity or the intrinsic average velocity.
@fluidmechanics101
@fluidmechanics101 5 жыл бұрын
Thanks for the correction Sayuj! Im going to pin this post so everyone can see it 😄
@sayujs7118
@sayujs7118 5 жыл бұрын
Thank you Aidan. I like all your videos.
@EclecticVibe
@EclecticVibe 5 жыл бұрын
Is the intendic average velocity also the true velocity?
@aidealczar6075
@aidealczar6075 5 жыл бұрын
@@fluidmechanics101 Hi Aidan and Sayuj, So in method 1 where data for pressure difference vs velocity is given by suppliers, is that "velocity" : superficial velocity?
@fluidmechanics101
@fluidmechanics101 5 жыл бұрын
Yep, it is the volume averaged velocity
@nageshjamge1372
@nageshjamge1372 4 жыл бұрын
Thanks. This is easy to understand porous zone.
@NachoPage92
@NachoPage92 Жыл бұрын
muchas gracias por la explicación
@HighVoltageCarnage
@HighVoltageCarnage 5 жыл бұрын
Thank you very much for the explanation!
@fluidmechanics101
@fluidmechanics101 5 жыл бұрын
No problem, glad you found it useful 😊
@ManojDash87
@ManojDash87 Жыл бұрын
Hi, sir thank you so much for such a clear and lucid explanation about porous media. I am calculating the porous coefficients for a thin perforated flow in the turbulent regime. While calculating the porous constants from polynomial curve fittings, I am getting viscous porous resistance, C1 as negative. Can you please explain such scenarios are possible and the physics behind the same.
@EclecticVibe
@EclecticVibe 5 жыл бұрын
Thank you for a great explanation of porous models! Saves a ton of time having to go through lots of notes to understand it. I can see that the correction about superficial velocity explanation is already mentioned in the comments. Can you please explain the difference between superficial velocity and true velocity?
@ehsansadeghi4486
@ehsansadeghi4486 4 жыл бұрын
Excellent explanation. thank you very much
@dazbazzabzad7658
@dazbazzabzad7658 5 ай бұрын
Nice video, thank you! I am using a porous medium to represent a spiral tube bank so the flow has a non negligible radial and circumferential velocity, how can I calculate c1 and c2 values for this?
@Jankinli
@Jankinli 8 ай бұрын
Thank you very much Doctor Aidan for your excelent explaination.I would like to ask whether it is necessary to add boundary conditions at the interface between the porous medium and the fluid region? When I simulate porous media, there is always a droplet splash phenomenon at the free surface or side wall, and then the vof analysis problems, the program can not run, I have not found the reason, want to ask the teacher what may cause this situation?
@zyama79
@zyama79 3 жыл бұрын
Thanks for this lecture and your clear art of explanation! One question, why you choose to set C_2 as big number and not C_1 to describe wall or very high flow resistance in particular direction?
@fluidmechanics101
@fluidmechanics101 3 жыл бұрын
If you just want to block the flow, you could do either C1 or C2 👍
@zyama79
@zyama79 3 жыл бұрын
@@fluidmechanics101 thank you for answering. I‘m struggling now with one problem connected to this lecture. I‘m modeling two-phase flow (h2o + h2) through porous media with Eulerian approach, capillary pressure and relative permeability in Fluent. Maybe you have some lecture or can suggest some good material dealing with similar issues and explains the theory behind it. Thanks & Kind Regards
@AMANPANDOH
@AMANPANDOH 2 ай бұрын
Thank you for this video it is really helpful. I just have one question, since we know the pressure drop across the porous media, during simulation can i convert my 3D geometry into a 2D geometry and while putting in coefficients divide by the actual length of porous media.?
@뉴레스
@뉴레스 2 жыл бұрын
Thank you for your very detailed explanation about porous domain in CFD. Could you please handle about heat transfer in porous domain also? I'm now using porous domain to calculate conjugate heat transfer of plate heat exchanger, I have difficulty in setting a heat transfer model.
@fluidmechanics101
@fluidmechanics101 2 жыл бұрын
Good suggestion, I will see what I can do
@tobiasjustesen308
@tobiasjustesen308 7 ай бұрын
Thank you very much Doctor! Do you have references for the theory?
@AmineAmine-kd1tq
@AmineAmine-kd1tq Жыл бұрын
Thank you very much sir. Please, how can i calculate these factors when ther is a melting of a phase change material (wax for example). So there is no flow. Just the solid wax melt inside the closed foa(porous media) when the temperature rises. Thank you before.
@fluidmechanics101
@fluidmechanics101 Жыл бұрын
Solidification and melting is very hard to do in CFD. Unfortunately I don't think I can help you. You might need specialist software for those calculations
@studyforfun5648
@studyforfun5648 Жыл бұрын
Great job, thanks a lot. I am trying to model a capillary membrane, can I use this model? Do u have any tips to calculate the c1,c2 if the porous media is as fine as a membrane (pore size is 7 µm)
@fluidmechanics101
@fluidmechanics101 Жыл бұрын
The flow is probably laminar through the holes (you can check Re). If it is laminar then you can use the analytical solution for flow through a pipe / parallel sides channel to derive the coefficients C1 and C2. In pretty sure if it is laminar then you will find that C2 = 0, and the C1 will depend on the viscosity and pore size
@HeitorvitorC
@HeitorvitorC 5 жыл бұрын
Hello Aidan, excellent presentation again, congratulations. Would you say we ought to use a porous zone method if the viscous forces are dominant in the flow? Im just trying to figure if it would be possible to simplfy even further the computational cost when one deals with a porous zone and choses to deal with the problem using Darcy law (first order velocity equation) instead of the NS equation... Best regards
@fluidmechanics101
@fluidmechanics101 5 жыл бұрын
I suppose it depends on your geometry. Adding an extra source term to NS doesnt really increase the computational cost (adding a porous zone). So if your overall geometry is simple, you could probably just use Darcys Law in a hand calculation. If your overall geometry is complex, just throw in the porous zone 😊
@jaimeavalosgauna771
@jaimeavalosgauna771 3 жыл бұрын
Thank you for this video. You really helped me. But I have a doubt in slide No. 16… when you are talking about the units. I can see the permeability unit is m^2 but what happened with the unit of seconds of the dynamic viscosity?
@范锷
@范锷 2 жыл бұрын
Hi! I found the same doubt, the units of pressure and C1/mu are both incorrect. Dimension of pressure shall be [M][L]^(-1)[T]^(-2), and dimensional of C1/t shall be [M][L]^(-3)[T]^(-1). However, the resulting dimension of alpha is correct as [L]^(2), LOL.
@tigo01
@tigo01 3 жыл бұрын
Thanks, super helpful! Just to clarify, you should mesh your porous zone as 1 cell thick in the porous direction, so when you divide your Coeff.s by t, it would come out right, correct? or if you have n-cells in the flow direction, you need to divide t by n?
@fluidmechanics101
@fluidmechanics101 3 жыл бұрын
Just divide by t. The source terms are applied per unit volume so they will multiply by the volume of the cells. More cells just distributes the source over more cells
@jakubrajnosek1619
@jakubrajnosek1619 Жыл бұрын
Quick question. When you were talking about C1/t being equal to dynamic viscosity/permeability it should be in kg/(m^3*s) should´t it? Because dynamic viscosity unit is kg/(m*s) and permeability is m^2. So when you divide it it should get kg/(m^2*s) or I am missing something? Because when I use polynomial formula in my pressure drop data the units check up because of delta_pressure=C1*U+C2*0,5*density*U^2 you need to get Pa = kg/(m/s^2). Correct me please if I´m wrong. :) Anyway thank you for great contect it was really helpful.
@sarathy319
@sarathy319 5 жыл бұрын
One suggestion . Can u present the topic regarding the modelling volumetric heat source within the components .The reason for asking this is it follows the same approach as the porous medium (Defining the source terms and how this source term works in defining the temperature) .Would highly appreciate .Thanks in advance .
@fluidmechanics101
@fluidmechanics101 5 жыл бұрын
What kind of heat source are you thinking? Im pretty sure you just take the actual heat source (in Watts) then divide by the volume of the cell zone (to get Watts/m3). You might need to use a UDF or User-Fortran or fvOptions if your source is more complicated
@bhootmehra
@bhootmehra Жыл бұрын
Thanks a lot. However, the pressure drop data is mostly available with respect to flow rate and not versus velocity in industry so curve fitting of DP versus flow rate to get the coefficients remain valid ? thanks
@fluidmechanics101
@fluidmechanics101 Жыл бұрын
If you think carefully about the flow area, then you can probably do the conversion to velocity
@onurmutlu4364
@onurmutlu4364 5 жыл бұрын
Thanks for your video. It is very useful to understand how to porous media is work. I want to model blood clot as a porous media but some paper publish only porosity and permeability values. How can I get C2 (head loss coefficient) without using velocity-pressure drop data?
@behnoushdaryaee
@behnoushdaryaee 4 ай бұрын
Excellent thank you so much for your time
@mashelbr
@mashelbr 2 жыл бұрын
Hello, this video was very useful for me thank you very much
@zhichaozhao172
@zhichaozhao172 3 жыл бұрын
Hi Dr.Aidan. In a car company, We use one set of the viscous and inertial coefficients for the pressure drop across the porous media(heat exchange), instead of three set of coefficients. that means air will flow in all direction, which is not correct behaviors, we expect air will only flow in one direction. Do you know why? Nobody knows in our company, we bought CFD methods.
@fluidmechanics101
@fluidmechanics101 3 жыл бұрын
Hi there! If you are expecting flow in a single direction, then you can make the loss coefficients much larger in the other directions. This will encourage the flow to go in the direction you want and give the correct loss coefficients. Remember: the flow will always try and follow the path of least resistance 👍
@furkanyildirim76
@furkanyildirim76 2 жыл бұрын
I see in many cases that people say we use the porous medium to define a geometry where there is no flow actually. Sir, do you know how we define a porous medium that does not allow any flow through it?
@fluidmechanics101
@fluidmechanics101 2 жыл бұрын
Yep, just set the resistance coefficients to be high. This will block most of the flow. Values of around 1000 seem to work quite well. If you set them too high the flow will stop completely and the solver may diverge, so be careful!
@sekhounekhalida6629
@sekhounekhalida6629 4 жыл бұрын
so useful, THANK YOU SO MUCH
@aleks7964
@aleks7964 4 жыл бұрын
In the video you mention that coefficients can be found in some textbooks. Could ypu specify which textbooks? I am particulary interested in heat exchangers. Thank you!
@fluidmechanics101
@fluidmechanics101 4 жыл бұрын
‘Internal Flow Systems’ by Miller is a really good source for loss coefficients. Sorry i forgot to mention it!
@vantrex3859
@vantrex3859 Жыл бұрын
Awesome Video, Thanks!
@akshaymugeraya782
@akshaymugeraya782 4 жыл бұрын
What about C1x & C1y? What should be the value as there will be high resistances in those directions as well
@fluidmechanics101
@fluidmechanics101 4 жыл бұрын
Yes, you can usually just pick a very high resistance coefficient and that is enough to stop the flow in those directions. Around 5000 should do it 👍
@ayseseymaarslantas592
@ayseseymaarslantas592 3 жыл бұрын
ı wathced the lesson carefully. thanks a lot. Do these coefficients change for heterogeneous and homogeneous porous regions?It does not change when it is calculated as an area. but i think it can change physically. my case study is airflow through people who are standing cramped up so heterogeneous permeability.
@fluidmechanics101
@fluidmechanics101 3 жыл бұрын
I suppose you could either average the people and do a homogeneous porous media or break your porous media into regions and assign different resistance coefficients for each region? (So effectively heterogeneous)
@mr.h.k.rashid1001
@mr.h.k.rashid1001 2 жыл бұрын
Thank you very much Doctor Aidan the porous media can be used for tube bundle. please , How I can used porous media with tube bundle using ANSYS, or what is the equations of C1/t and C2/t thank you very much Hayder kraidi Rashid
@fluidmechanics101
@fluidmechanics101 2 жыл бұрын
You will need to look up empirical equations for the pressure drop (Euler number) for arrays of horizontal cylinders. Then you can equate these equations to the formulae for the source terms in Fluent and rearrange for the coefficients C1 and C2
@RakeshKumar-jy1zx
@RakeshKumar-jy1zx 2 жыл бұрын
How can we double the porosity value for the current case with respect to governing equations. Means which term in the governing equation will tell me about the porosity value?
@santhoshinib8684
@santhoshinib8684 2 жыл бұрын
Hi.. Your lectures are very easy to understand.. Can you please make a video on conjugate heat transfer...
@fluidmechanics101
@fluidmechanics101 2 жыл бұрын
Good idea! I will add it to my list
@himanshubanait9166
@himanshubanait9166 5 жыл бұрын
Sir, Your videos are very good and easy to understand. Will you please upload a video on multiphase flow and free surface flow.
@fluidmechanics101
@fluidmechanics101 5 жыл бұрын
Yep, I am working on this one. It all really depends on the interface sharpening algorithm used for the convection term (have a look at my Eulerian multiphase video for a brief overview)! Interface sharpening is quite tricky, so I am still working on it 😄
@gagank9199
@gagank9199 3 жыл бұрын
@8:27 you said that velocity will be increased due to reduction in area but as you considered before a cross section of equal area as that of pore then there will be no increase in velocity ,so what about superficial velocity then
@eshetugetahunmulat1138
@eshetugetahunmulat1138 3 жыл бұрын
Very nice lecture
@MalcolmAkner
@MalcolmAkner 4 жыл бұрын
Super useful stuff, thank you for all of this! :D
@fluidmechanics101
@fluidmechanics101 4 жыл бұрын
I would have a look and see if you can find any papers or textbooks with loss coefficients for heat exchangers. I cant recommend any off the top of my head but you should be able to find some with a quick google search
@omidtutunchian3304
@omidtutunchian3304 3 жыл бұрын
I have a question. the velocity we use in pressure drop equation to calculate C1 and C2 is physical velocity or superficial velocity in porous medium?
@fluidmechanics101
@fluidmechanics101 3 жыл бұрын
Superficial 👍
@rajatthakur5438
@rajatthakur5438 Жыл бұрын
Kindly do detail video for MSMD models
@ravikarantripathi7228
@ravikarantripathi7228 2 жыл бұрын
Really very very helpful.....
@JohnDoe-oe2xw
@JohnDoe-oe2xw 5 жыл бұрын
Shouldn’t the units be m^2/s in slide 16?
@fluidmechanics101
@fluidmechanics101 5 жыл бұрын
Ive just been checking through and it looks like ive made a mistake 😅 especially after insisting on being careful with units! C1/t should have units of [kg/m3 s]. Hence the time unit in the numerator should cancel out to give the correct units of [m2] for alpha (the face permeability). Sorry for the slip up guys, and well spotted on the mistake!
@hirashijas5378
@hirashijas5378 7 ай бұрын
can porous zones be used to model a membrane like the one used in water treatment like reverse osmosis or membrane distillation?
@sangappardasar.3223
@sangappardasar.3223 4 жыл бұрын
thank you so much professor, How to input the values of relative humidity (moisture content) as inlet condition and check the moisture content in the porous zone? Please tell us how to do this.
@osckar095
@osckar095 2 жыл бұрын
U are a legend mate!!
@闫建东
@闫建东 4 жыл бұрын
Thank you very much! One more question about the relationship between the volume porosity and the pressure loss through the porous domain. i am using the CFX to simulate the flow through a gauze. And I've ran lots of cases and found that the total pressure loss not only determined by the loss coefficient but also the volume porosity as well. can you explain this a little bit? fantastic video , thank you again.
@joseyovanygalindodiaz4767
@joseyovanygalindodiaz4767 2 жыл бұрын
I love u man, great video
@kanglingwu5224
@kanglingwu5224 3 жыл бұрын
Thank you so much for this wonderful videos! And I still have a question: How about the energy equation of fluid in the Porous zones? Some papers seems only considered the heat conduction between fluid & solid porous layers, while Ansys Fluent seems used different method, and I'm still quite confused about this.
@lorenzopiazza9935
@lorenzopiazza9935 4 жыл бұрын
Thanks a lot !!!!! this video is very helpful
@sakurasuper
@sakurasuper 3 жыл бұрын
Thanks a lot for your excellent videos, really helpfull ! I have a question regarding method 1 for deriving c1 and c2 (Curve fitting on experimental data). Whic velocity is considered as x-axis ? Local velocity through the obstacle or velocity just upstream the obstacle ?
@fluidmechanics101
@fluidmechanics101 3 жыл бұрын
Velocity just upstream (so based on the superficial velocity)
@sakurasuper
@sakurasuper 3 жыл бұрын
@@fluidmechanics101 thanks a lot 👍
@fadakfadak9781
@fadakfadak9781 4 жыл бұрын
Hello sir, if I have open channel flow with gravel bed can I simulate it as a porous zone and is thickness of gravel bed can be consider the thickness for porose media (t )
@fluidmechanics101
@fluidmechanics101 4 жыл бұрын
Yep! You sure can
@CyBeRpw
@CyBeRpw 4 жыл бұрын
Hello, can you please recommend some text book for coeff. calculation?
@fluidmechanics101
@fluidmechanics101 4 жыл бұрын
Yes, have a look at ‘internal flow systems’ by D.S.Miller. I think there are pdfs online, so you probably dont even need to buy the book 👍
@muhammadishaq6417
@muhammadishaq6417 4 жыл бұрын
Thanks very much. Very informative.
@ismahanmaazouz6847
@ismahanmaazouz6847 3 жыл бұрын
Hello professeur In the porous zone is the value of the source terms in the solid or fluid (in fluent )?
@fluidmechanics101
@fluidmechanics101 3 жыл бұрын
Your cell zones should be a fluid. Then you need to tick the box 'porous zone'. This will open up the options which allow you to fill in the coefficients for the zone
@ismahanmaazouz6847
@ismahanmaazouz6847 3 жыл бұрын
@@fluidmechanics101 think you professeur
@barrjohnm
@barrjohnm 5 жыл бұрын
How does somebody get familiar with CFD? Mainly I am talking about the programming. I am comfortable using python, MATLAB and very proficient with calculus as well as vector calculus. Any advice would be extremely appreciated. However, I have no experience with CAD.
@jonasmuller4856
@jonasmuller4856 5 жыл бұрын
I can recommend you this course from Boston University: kzbin.info/www/bejne/aWbYn4SdiMaHbpo with additional material on this website: lorenabarba.com/blog/cfd-python-12-steps-to-navier-stokes/
@fluidmechanics101
@fluidmechanics101 5 жыл бұрын
Or you could just jump in and try some OpenFOAM 😄 all the source code is there and there are plenty of test cases, so you wont need to do any CAD/meshing if you just want to have a go and see how the code works. (Just google OpenFOAM and you can find it)
@qingren3221
@qingren3221 2 жыл бұрын
what about for the situation that Re is large and the flow is compressible?
@fluidmechanics101
@fluidmechanics101 2 жыл бұрын
Good question. It's not something I have looked into. I am guessing that there may be additional terms needed to account for the increased losses
@balapesar
@balapesar 4 жыл бұрын
Thanks for the very nice lecture! One question: If a porous media is made of entangled fibers and the liquid is wicked into it by capillary force, how the C values should be calculated there? (Do we need a microscopic image to measure the average size of microchannels between the fibers, or what)
@fluidmechanics101
@fluidmechanics101 4 жыл бұрын
Do you have any measurements of the pressure drop?
@balapesar
@balapesar 4 жыл бұрын
Fluid Mechanics 101 We have a graph for wicking length vs. time. Can we use the wicking rate to determine C value?
@fluidmechanics101
@fluidmechanics101 4 жыл бұрын
Sorry Hossein, i dont really know what a wicking length is? Maybe ask your colleagues
@gauravkhantwal1353
@gauravkhantwal1353 4 жыл бұрын
The explanation for superficial velocity was incorrect; the one you described is called interstitial velocity.
@fluidmechanics101
@fluidmechanics101 4 жыл бұрын
Yes, i am aware that this is a mistake! Sorry all 🤦‍♂️
@jakubrajnosek1619
@jakubrajnosek1619 Жыл бұрын
Hi, thank you for Your great content. I wanted to ask if it would be possible to model a metal foam for heat transfer in natural and forced convection like this. :) Thank you.
@schrummy14
@schrummy14 3 жыл бұрын
Hello, I have been looking into modeling porous domains in regards to grain storage and was wondering if you had any thoughts on this. Looking at the literature, I have found pressure drops of (say corn) across a meter bed. Using the curve fitting method, I have found values of the linear term to be in the order of 10+ Million and the quadratic term to be in the order of 10,000. I would be happy to share the google spread sheet with you if you want to see it. Thank you.
@fluidmechanics101
@fluidmechanics101 3 жыл бұрын
From your values it looks like you can just neglect the viscous term and go with just the quadratic term. 10,000 is high so maybe do a quick easy CFD simulation with flow in a cuboid shaped domain with a block of porous material and check that you are getting the pressure drop you expect. If that works and you are happy then go ahead with your full CFD calculation
@schrummy14
@schrummy14 3 жыл бұрын
@@fluidmechanics101 Went back and redid the papers test in cfd, and the values are correct. I ended up using simpleFoam with different relaxation factors (0.2 for pressure and 0.3 for velocity and turbulence values) and everything is working better and, more importantly, converging. Thank you.
@fluidmechanics101
@fluidmechanics101 3 жыл бұрын
Amazing! Nice work!
@bhootmehra
@bhootmehra Жыл бұрын
I have a cooling circuit including multiple components like motor, inverter, compressor etc. I want to model the circuit in Fluent while incorporating the pressure drop of each component using porus media. However i am not sure how to take care about the thickness as each component has its cold plate and i do not know their dimensions. Is this a correct approach i am adopting ? thanks
@fluidmechanics101
@fluidmechanics101 Жыл бұрын
Do you know the pressure drop from each component? Or do you have any data / can approximate it? You can use an incorrect thickness as long as you ensure that the pressure drop is the same by adjusting the loss coefficient
@punkisinthedetails1470
@punkisinthedetails1470 4 жыл бұрын
How would the tube banks work? Is this a heat exchanger?
@fluidmechanics101
@fluidmechanics101 4 жыл бұрын
Yes, it is a type of heat exchanger. If you think of a cross-sectional slice through the tube banks, then you can model this as a porous zone. The reason that you might not want to model the tubes explicitly is that the flow separation off the cylinders is complex, unsteady and requires a high level of grid (and temporal) resolution. So it is often easier to model a set of cylinders as a porous zone instead. This also allows you to perform a steady simulation 😊
@punkisinthedetails1470
@punkisinthedetails1470 4 жыл бұрын
@@fluidmechanics101 Thanks for the feedback. Extra layers on all the tubes would be excessive and vortex street for each one. My other question was how to handle something that doesn't just hold up the flow like a filter but something that redirects flow like a louvre or parallel plates at an angle to the incoming flow? Another great video and explanation all the best for 2020.
@nileshgaikwad5021
@nileshgaikwad5021 2 жыл бұрын
Any specific reason to write modulus of velocity (IUI) in the inertial term of pressure drop equation ?
@fluidmechanics101
@fluidmechanics101 2 жыл бұрын
Yep, to make sure that the pressure drop is in the opposite direction to the velocity vector, regardless of coordinate system (- U |U|) will always have a sign that is the opposite of U)
@gsaikumarreddy7355
@gsaikumarreddy7355 3 жыл бұрын
thank you...
@cristinaboscariol533
@cristinaboscariol533 4 жыл бұрын
Hi! Thanks for the amazing video, it' very interesting. I have one question about how the solver takes in account the of porous media. Does the volume of fluid recognize there is a solid medium in the domain? So for example, if I have a full region of porosity with a percentage of void area of 50%, will the fluid be able to fill only half of the region?
@kartikjain4885
@kartikjain4885 2 жыл бұрын
ANSYS fluent doesn't recognize any solid domain. It only applies the momentum sink term once you activate the porous media model.
@swinmosh
@swinmosh 9 ай бұрын
Absolute legend
@ivanettbarreto9249
@ivanettbarreto9249 4 жыл бұрын
Hi, Can you please recommend me a book where I can get empirical data for C2?
@fluidmechanics101
@fluidmechanics101 4 жыл бұрын
‘Internal Flow Systems’ by D.S.Miller has lots of empirical data. I normally use that 👍
@ivanettbarreto9249
@ivanettbarreto9249 4 жыл бұрын
@@fluidmechanics101 Thank you! Your video was very helpful!
@MrZorfan
@MrZorfan 2 жыл бұрын
thanks for your eplanation
@sanjaykumaryadav3186
@sanjaykumaryadav3186 4 жыл бұрын
sir can you make videos on discreption of turbulent flow navier stokes equation
@fluidmechanics101
@fluidmechanics101 4 жыл бұрын
You can find a good description of the discretisation of N-S in my fundamentals course (which is on my website: www.fluidmechanics101.com ) or check out my video titled ‘The Finite Volume Method’ 👍
@sanjaykumaryadav3186
@sanjaykumaryadav3186 4 жыл бұрын
Thank u sir.
@kaushik6502
@kaushik6502 5 жыл бұрын
Hello, Great explanation. Is it possible to use this method for the simulation of flow through swirl diffuser? I am doing the simulation of airflow in a clean room which has diffuser inlets. Thanks
@fluidmechanics101
@fluidmechanics101 5 жыл бұрын
Yep, you can use it for the filters on the inlet and outlets to the clean room. Try and get some measures data for the pressure drop across the filters (usually the manufacturer will have this)
@punkisinthedetails1470
@punkisinthedetails1470 4 жыл бұрын
@@fluidmechanics101 how can the porous zone discharge with the swirl flow won't it discharge perpendicular. Same concerns for a louvre. How do you make sure it has the desired polarizing effect in terms of flow.
@nimisha9849
@nimisha9849 5 жыл бұрын
Sir...really helpful...thanks...I have to model an earthen dam by using ANSYS...can it possible...have you any related vedios?
@fluidmechanics101
@fluidmechanics101 5 жыл бұрын
What are you trying to simulate? A dam break or the hydrostatic load?
@vineetsingh8047
@vineetsingh8047 4 жыл бұрын
Useful Video!!!
@alpabhatt8101
@alpabhatt8101 3 жыл бұрын
hi its indeed useful to me ... i want to learn specific issues of cfd can you pls help me?
@studyforfun5648
@studyforfun5648 2 жыл бұрын
Thanks a lot for this video, it helped me understand where to start learning about the porous zone. I have to model a capillary-membrane, whose wall is permeable and the water enters from the right side. Hier one has a laminar flow, which means Darcy's law is accepted. I am trying to find out c1, c2, could you please support me with some tipps? best wishes, Venesa
@fakezedd
@fakezedd 2 жыл бұрын
Can porous zones be applied to filter media in CFD?
@fluidmechanics101
@fluidmechanics101 2 жыл бұрын
Pretty sure they can if you know the pressure drop across the filter media
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