CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   FLOW-3D (http://www.cfd-online.com/Forums/flow-3d/)
-   -   unit ? (http://www.cfd-online.com/Forums/flow-3d/115123-unit.html)

faris March 24, 2013 12:04

unit ?
 
Dear All,

I'm new in Flow-3D.
I work on physical models. In Weirs "free surface".
I have inquire: When we draw the shape in AutoCAD (eg x = 1 m). We open with MiniMagics shows "x = 1000 mm." When we insert the form in Flow-3D shows me the dimension "x = 1000". Knowing i work in the system (SI).
"x = 1000" in Flow-3D, Does this unit in millimeters or meters?
help me please.

Thank you,
Faris

dmilano March 25, 2013 10:03

FLOW-3D does not track units, so you just need to make sure that all inputs are in a consistent unit system (e.g. SI).

faris March 25, 2013 15:09

Thank you very much for your interest, I will try it.

faris March 27, 2013 05:13

Hi dmilano,

I have entered all the inputs in the system and a consistent unit.
The smaller dimension of the shape is (x = 0.002 m). When we do the mesh, The cell number up to more than 40 million. Is this normal ?

dmilano March 27, 2013 10:35

40M is large, but some problems require this many cells - it just depends on the size of the domain and the required cell size. Even so, it is worth double-checking your inputs to make sure that nothing was missed.

faris March 31, 2013 06:08

Hi dmilano,

I tried several attempts but did not succeed. Simulations stopped after taken a long time and i get an error message "Time-step size < dtmin".
Please if you have time, I send to you a prepin (input file) to investigate and show me the Mistake. Please help me.

saeedtk June 25, 2013 02:24

this error can have several reasons:
first of all check the manual there is part about troubleshooting.
the consider your mesh, first use a very coarse mesh if it again happen chand the order of solver or ur turbulence models.

good luck


All times are GMT -4. The time now is 13:31.