how can i create a transient analysis ?

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

 December 4, 2007, 09:44 how can i create a transient analysis ? #1 KADONED Guest   Posts: n/a hello i would like to have a FSI 2way where the input will change pressure from 10 bar to 100 and then to 2000. the transient analysis will take 1 second , from the beginning the pressure will be 0 bar then until 0.3 second it will increase to 10 bar and it will stay there until 0.6 second, at the 0.6 the pressure will increase to reach the 2000 bar at second 1. any help how to do the expressions? thanks in advance

 December 4, 2007, 15:15 Re: how can i create a transient analysis ? #2 jakjak Guest   Posts: n/a KADONED, where do you plan to implement this transient pressure effect ? i.e. at inlet/outlet? jakjak

 December 4, 2007, 16:40 Re: how can i create a transient analysis ?------W #3 CycLone Guest   Posts: n/a You can either create an expression for the changes using step functions, or create a 1D function in Pre with the values and use this for your boundary condtion. The 1D function will interpolate between points, so you may need to put two points close together to get a sharp change at 0.3 and 0.6 seconds (i.e. 0 [bar] at .29 [s] and 10 [bar] at 0.3 [s]. The step function would look like this: Pinlet = 10 [bar] * step((t-0.2999 [s])/1[s]) + (2000 [bar] - 10 [bar]) * step((t-0.5999 [s])/1[s]) The step() function takes a non-dimensional argument (hence dividing by 1 [s]) and evalues to 0 if the operand is negative, 0.5 if it is equal to zero, and 1 if it is positive. Just be careful about having sudden changes in pressure like this. It's actually quite non-physical, so using the 1D function and leaving a little more time between pressure increments may yield better results. -CycLone

 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 Hikachu OpenFOAM Native Meshers: blockMesh 0 June 20, 2011 09:03 kmgraju CFX 4 May 11, 2011 04:30 naveen_010 STAR-CD 0 February 1, 2011 14:17 hcy FLUENT 0 September 16, 2009 16:41 Richard CFX 1 December 4, 2008 18:40

All times are GMT -4. The time now is 11:50.