Need a help concerning a pure convection problem

March 14, 2009, 12:14

Hello all.

I am studying a book entitled 'An Introduction to CFD : FVM approach' by versteeg.

I found two dimensional pure convection problem with discontinuity, and QUICK solver was developed for that problem.

However, my code blowed up in the middle of running. I think source term of the discretized equation is so big which cause the system of the discretized equation to be unstable.

Is there anyone who have an experience to deal with my trouble?

I have a document of the relating equations and numerical descriptions and i can share if leaving e-mail address.

Please reply.

Regards.

harishg · March 15, 2009, 20:44

What was the time marching scheme that was employed ? The explicit schemes have issues with stability. Did you test your code for a simple case like 1-D shock tube problem to check the implementation.

9mile · March 15, 2009, 22:26

My code use space marching called line-by-line method mentioned in chapter 7 of the book. I think the method may be implicit.
What is your opinion applying line-by-line method with QUICK to pure convection problem?
I think my discretized equation applied by QUICK is ok but next step related to line-by-line method is not sure whether is good or bad in this case.
Do you have any suggetions to marching method?
Now, i'm trying to implement relaxation technique but i can not be sure what results i'll get because the author does not mention in the book which marching method he used.
Also i'll consider 1-D shock tube problem.
Thank you for reply!

Far · March 16, 2009, 08:55

which scheme you are using for pressure correction

9mile · March 16, 2009, 10:48

Thank you for reply.

It doesn't need any pressure correction.
The governing equation is as follows.

rho*u*(partial phi)/(partial x) + rho*v*(partial phi)/(partial y) =0

And each of face value for 'phi' in FVM is applied by QUICK method and for multi-dimension, line-by-line method is used.

That's all.

jugghead · March 17, 2009, 06:12

If it has discontinuities you can use CICSAM scheme.

Nishu · July 8, 2009, 14:24

Hi,

Can someone send me the 1D code for shock tube problem at babuu.nishu@gmail.com? I need it for my research.

Thanks alot
Nishant

March 14, 2009, 12:14	Need a help concerning a pure convection problem	#1
happysmile Guest Posts: n/a	Hello all. I am studying a book entitled 'An Introduction to CFD : FVM approach' by versteeg. I found two dimensional pure convection problem with discontinuity, and QUICK solver was developed for that problem. However, my code blowed up in the middle of running. I think source term of the discretized equation is so big which cause the system of the discretized equation to be unstable. Is there anyone who have an experience to deal with my trouble? I have a document of the relating equations and numerical descriptions and i can share if leaving e-mail address. Please reply. Regards.

March 16, 2009, 08:55	scheme	#4
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	which scheme you are using for pressure correction

March 16, 2009, 10:48		#5
9mile New Member Neo Join Date: Mar 2009 Posts: 18 Rep Power: 17	Thank you for reply. It doesn't need any pressure correction. The governing equation is as follows. rhou(partial phi)/(partial x) + rhov(partial phi)/(partial y) =0 And each of face value for 'phi' in FVM is applied by QUICK method and for multi-dimension, line-by-line method is used. That's all. Last edited by 9mile; March 16, 2009 at 11:17.

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March 15, 2009, 20:44		#2
harishg Senior Member N/A Join Date: Mar 2009 Posts: 189 Rep Power: 17	What was the time marching scheme that was employed ? The explicit schemes have issues with stability. Did you test your code for a simple case like 1-D shock tube problem to check the implementation.

March 15, 2009, 22:26		#3
9mile New Member Neo Join Date: Mar 2009 Posts: 18 Rep Power: 17	My code use space marching called line-by-line method mentioned in chapter 7 of the book. I think the method may be implicit. What is your opinion applying line-by-line method with QUICK to pure convection problem? I think my discretized equation applied by QUICK is ok but next step related to line-by-line method is not sure whether is good or bad in this case. Do you have any suggetions to marching method? Now, i'm trying to implement relaxation technique but i can not be sure what results i'll get because the author does not mention in the book which marching method he used. Also i'll consider 1-D shock tube problem. Thank you for reply!

March 17, 2009, 06:12		#6
jugghead New Member Join Date: Mar 2009 Posts: 27 Rep Power: 17	If it has discontinuities you can use CICSAM scheme.

July 8, 2009, 14:24		#7
Nishu Member Nishant Kumar Join Date: Jun 2009 Posts: 32 Rep Power: 17	Hi, Can someone send me the 1D code for shock tube problem at babuu.nishu@gmail.com? I need it for my research. Thanks alot Nishant