Really looking forward to the next part - the terms of steady, transient, and pseudo-transient are quite vague to novices, especially when there is no sufficient guidance. I stand by what I've commented for the talk about residuals - this channel should be officially recommended for CFD newbies in CFD software manuals and universities.
From what I have understood, Explicit Relaxation is applied to the field (updated) value after they are solved using the conventional AT=B matrix equation. Implicit Relaxation are directly applied to the conventional AT=B equation. Please Dr. Aiden correct me if I am wrong. Thanks again for your efforts!! 😃
you are doing a great job. I never have found u tube channel like this. You explain very well. If you can explain photoacoustic waves and governing physics equations regarding photoacoustic and how photoacoustic effect relates to CFD, I appreciate it a lot..
I have a question. It seems that set alpha to 1 is the same as the unrelaxation case. However, in my interFoam case, setting alpha to 1 a converge is achieved, but deleting the relaxationFactors in fvSolution leads to a divergence. How to explain this? Thanks!
I read the OpenFoam UserGuide: alpha = 1 leads to guaranteed matrix diagonal equality/dominance. It seems that in that case the relaxation algorithm still does something?
This is a really good video. On a side note, are there any textbooks that you can recommend for studying vector calculus and linear algebra? There are engineering textbooks and then there are textbooks that are relevant to CFD research. Have you come across any such textbooks ?
For linear algebra the book by Saad 'iterative methods for sparse linear systems' is really good and it's free! Just give a Google search and you should find it. Sadly I don't have anything good for vector calculus. The OpenFoam manuals are pretty good for vector calculus that is related to CFD
Thank you for the fantastic lecture. Could I please ask is it rare to use very small URF for example 0.01 to solve the problem? I am having convergence difficulties in solving swirling flow, after your lecture, I am thinking to try very small URF to stabilise the simulation as swirling is unsteady phenomenon in nature. Could you please advise a little bit on this? Many thanks in advance.
Thank you! Looking forward to the next part in the series. I can get any run to converge by reducing the pseudo time step Courant number to around 0.1 and using SIMPLEC solver. I wonder why and if the results are accurate
Thanks for ur explanation. Do u know about high order relaxation ? Fluent said it is used for additional term in high order term, but in the formulation, they use phi intermediate instead of phi calc. I don't know what is phi intermediate, can u explain ? thanks
![[CFD] Relaxation in CFD (Part 3) - Pseudo Transients](http://i.ytimg.com/vi/GvgXZC06UgA/mqdefault.jpg)
![[CFD] Relaxation in CFD (Part 3) - Pseudo Transients](/img/tr.png)
![[CFD] Relaxation in CFD (Part 1) - Explicit Relaxation, Under-Relaxation Factor](http://i.ytimg.com/vi/GSsv2ncNJN8/mqdefault.jpg)
![[CFD] Multi-Grid for CFD (Part 1): Smoothing, Aliasing and the Correction Equation](http://i.ytimg.com/vi/4UoJpazu_fU/mqdefault.jpg)
![[CFD] Residuals in CFD (Part 1) - Understanding Residuals](/img/n.gif)
Great lecture. Love the emphasis on information relevant to CFD users. Makes it easier to digest
Really looking forward to the next part - the terms of steady, transient, and pseudo-transient are quite vague to novices, especially when there is no sufficient guidance. I stand by what I've commented for the talk about residuals - this channel should be officially recommended for CFD newbies in CFD software manuals and universities.
Yes! I am planning to clear all of this up by the end of the series
i totally agree
nice explanations!, i like the OpenFOAM details that u give in ur talks.. please keep doing good work.. thanks!
You are just awesome Sir, I really love learning your lectures Sir, you are the BEST!!!
Amazing lecture. big thank you.
Interesting video series. 100% for the explanations. Keep doing good work. Thanks. ☺️👍
Absolutely brilliant video. congrats.
Waiting for it, thank you
Great lecture , you have all my gratitude
Enjoyed as always!
thank you for very informative talk.
Excellent inputs
Please open those private videos as well. Your videos are very informative. Thanks
From what I have understood,
Explicit Relaxation is applied to the field (updated) value after they are solved using the conventional AT=B matrix equation.
Implicit Relaxation are directly applied to the conventional AT=B equation.
Please Dr. Aiden correct me if I am wrong.
Thanks again for your efforts!! 😃
Yes! Exactly correct
@@fluidmechanics101 Thank You!
you are doing a great job. I never have found u tube channel like this. You explain very well. If you can explain photoacoustic waves and governing physics equations regarding photoacoustic and how photoacoustic effect relates to CFD, I appreciate it a lot..
Very informative. Thanks.
I have a question. It seems that set alpha to 1 is the same as the unrelaxation case. However, in my interFoam case, setting alpha to 1 a converge is achieved, but deleting the relaxationFactors in fvSolution leads to a divergence. How to explain this? Thanks!
I am not too familiar with interFoam but simpleFoam definitely needs relaxation factors less than 1!
I read the OpenFoam UserGuide: alpha = 1 leads to guaranteed matrix diagonal equality/dominance. It seems that in that case the relaxation algorithm still does something?
Ahhh ok, I think the latest versions of OpenFOAM may have changed what 'alpha' actually does. I will need to have a read of this
Feels like knowed nice concepts
This is a really good video. On a side note, are there any textbooks that you can recommend for studying vector calculus and linear algebra? There are engineering textbooks and then there are textbooks that are relevant to CFD research. Have you come across any such textbooks ?
For linear algebra the book by Saad 'iterative methods for sparse linear systems' is really good and it's free! Just give a Google search and you should find it. Sadly I don't have anything good for vector calculus. The OpenFoam manuals are pretty good for vector calculus that is related to CFD
@@fluidmechanics101 Thank you.
There’s also Moukalled, Mangani & Darwish (2016):
antivirus.uclv.edu.cu/update/libros/Engineering/The%20Finite%20Volume%20Method%20in%20Computational%20Fluid%20Dynamics%20-%20F.%20Moukalled%2C%20L.%20Mangani%2C%20M.%20Darwish%2C%201st%20ed.%202016%20-%20978-3-319-16874-6.pdf
Thank you for the fantastic lecture. Could I please ask is it rare to use very small URF for example 0.01 to solve the problem? I am having convergence difficulties in solving swirling flow, after your lecture, I am thinking to try very small URF to stabilise the simulation as swirling is unsteady phenomenon in nature. Could you please advise a little bit on this? Many thanks in advance.
Probably better to go with a transient solver 👍
Thank you! Looking forward to the next part in the series. I can get any run to converge by reducing the pseudo time step Courant number to around 0.1 and using SIMPLEC solver. I wonder why and if the results are accurate
Thanks for ur explanation. Do u know about high order relaxation ? Fluent said it is used for additional term in high order term, but in the formulation, they use phi intermediate instead of phi calc. I don't know what is phi intermediate, can u explain ? thanks
Not sure. If the manual doesn't say then I guess we will never know! (Unless we could read the mind of ANSYS 😅)
@@fluidmechanics101 I think it's the same as phi calc :) but i'm not sure, haha
👍
sir, im waiting for ur species transportation lectures...