Menu

Discussion Forum

New Discussion
Filter

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Supersonic flow

Posted Jul 23, 2012, 3:11 p.m. EDT 1 Reply

Jhon Freddy Alfonso Serrano
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

I´ve a problem when I try to simulate a basic nozzle inducing supersonic flow in hmnf. I define a subsonic inlet (Mach number/ high pressure) and an outlet (pressure or supersonic condition). Trying to solve the model, i've encountered with a problem that I don´t understand; the message is:

Failed to find a solution.
Segregated group 1

Singular matrix.

There are 33 void equations (empty rows in matrix) for the variable mod1.hmnf.TWall.
at coordinates: (-32.0383,580.87), (-33.1644,583.411), (-34.5208,585.837), (-70,600), (-36.0958,588.127), ...
and similarly for the degrees of freedom (empty columns in matrix).
Returned solution is not converged.

My question is. ¿What´s the meaning of "mod1.hmnf.TWall?¿How I define it in High Mach Number Flow?

Thanks.
1 Reply Last Post Sep 4, 2012, 8:25 a.m. EDT
COMSOL Moderator

Hello Jhon Freddy Alfonso Serrano

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.

Friedrich Baumann
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Sep 4, 2012, 8:25 a.m. EDT
Hi,

you can't find "mod1.hmnf.TWall since you haven't a solution. I was wondering too. I think you have a problem with your initial values and boundary-conditions. Or there is a sharp edge or point in your geometry you should supress before meshing.

I suppose it stopped in iteration no 1?

Bye
Hi, you can't find "mod1.hmnf.TWall since you haven't a solution. I was wondering too. I think you have a problem with your initial values and boundary-conditions. Or there is a sharp edge or point in your geometry you should supress before meshing. I suppose it stopped in iteration no 1? Bye

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content