CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > CFX

Exporting results and Mach number calculation

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Search this Thread Display Modes
Old   July 14, 2010, 14:05
Default Exporting results and Mach number calculation
New Member
Pawan Kumar
Join Date: Apr 2010
Posts: 15
Rep Power: 10
pawan1989 is on a distinguished road
Good afternoon. A few quick questions, nothing life-threatening but was interested to know if anyone had any insight.

1) Mach number. The speed sound as per CFX is calculated using \sqrt{ \frac{\gamma P}{\rho}}
I am using air ideal gas. Pressure, I have set the reference pressure as 5500 pascal (such that for my problem the relative static pressure is 0, hence my total/absolute pressure is 5500). Gamma is 1.4. How does CFX calculate \rho from the molar mass (kg /kmol ) ?
In fluent, i used to set the Mach number to what I wanted (around 6) and it gave me a corresponding velocity it used to initialize the problem. The same velocity, when input into CFX gave me a free stream mach (I found from my results) closer to 7.

I did a simple interpolation and figured out my new velocity and am running at the desired mach now but I am still curious.

2) Exporting results. I am exporting to cgns. My domain has about 5 boundaries (2 inlets, 1 outlet, 1 wall, 1 sym plane).
When I export, is it possible to export just the results of the symmetry plane instead of all the boundaries? The "export boundary values only" solves half the problem (I think) in that it only exports the boundary information, not the vast fluid domain inside. But still the results file (that includes all 80 transient timesteps) is enormous, on the order of a couple gigs. It would really really help if I could export just the sym plane solution.

Thanks for the help
pawan1989 is offline   Reply With Quote


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
mach number and selection of the fluent solver turbinesv FLUENT 4 April 24, 2011 01:14
Strong oscillation at transonic mach number martingariepy FLUENT 2 May 12, 2009 12:40
mach number and CFX 11.0 solver turbinesv CFX 5 January 5, 2009 06:43
Mach number in Post processor Ramu Maddi CFX 3 August 17, 2007 11:06
non-dimensional analysis in Fluent Endee FLUENT 8 September 7, 2005 17:16

All times are GMT -4. The time now is 16:13.