# time step in flow3D

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

 March 27, 2014, 10:22 time step in flow3D #1 Member   mina salehi Join Date: Jan 2014 Posts: 30 Rep Power: 5 Hi All. I have many questions about Flow 3D. I've just started working with the software. 1) selection of time step in Flow 3D is basedon? I don't know, how select time step? 2)what is selected finish condition based on ? finish time or fill fraction? 3) How to determine the number of mesh cells? Thanks alot for your guiding.

 March 28, 2014, 06:39 #2 New Member   Maxime Join Date: Mar 2014 Posts: 16 Rep Power: 5 Hello, 1) What do you mean by "basedon" ? Flow 3D calculates the best time step during simulation. But you can define min and max time step in "numerics" option (optional). 2) Depend on what you search. What do you want to simulate with Flow 3D ? If you simulate cavity filling (for exemple casting process), "Fill fraction" is good. To watch water comportment into a tube, you have to select "Finish time". 3) With the "FAVOR" method ("Mesh & Geometry" tab). You apply a cell size (or cells number), then you can watch your geometry modelisation with these mesh conditions. Reduce cell size if the geometry isn't correctly modelised. Good luck mina00 likes this.

 March 30, 2014, 04:02 #3 Member   mina salehi Join Date: Jan 2014 Posts: 30 Rep Power: 5 Dear macsim Thanks a lot. I do not know how I would choose the time step? I want to simulate flow over a weir. Which one should I choose? Fill fraction or Finish time? Thanks.

 March 30, 2014, 07:23 #4 New Member   Maxime Join Date: Mar 2014 Posts: 16 Rep Power: 5 Hello mina, I think you can do a first simulation with an initial time step at 0.01 (numerics option). And depending results, try to minimize this initial time step. For flow over a weir you have to choose finish time. For its value, try to calculate it depending of your simulation conditions (where the fluid is starting, during how many time you want to see flow over the weir...). Have a nice Sunday. mina00 likes this.

 April 4, 2014, 13:40 #5 Member   mina salehi Join Date: Jan 2014 Posts: 30 Rep Power: 5 Thanks a million

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Artex85 OpenFOAM Running, Solving & CFD 11 February 16, 2017 14:40 chrisb2244 OpenFOAM Running, Solving & CFD 3 July 1, 2014 16:40 sivakumar OpenFOAM Running, Solving & CFD 7 March 17, 2013 07:37 cyberbrain OpenFOAM 4 March 16, 2011 10:20 zhajingjing OpenFOAM 0 April 28, 2010 04:35

All times are GMT -4. The time now is 07:51.