# Help with Boundary Conditions

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

 October 6, 2007, 02:34 Help with Boundary Conditions #1 chun wee Guest   Posts: n/a Hi, I have problem in assigning BC for propeller simulation. I use fan BC to represent the propeller. I draw a tube isolating the fan surface. The BC is pressure inlet --> fan --> pressure outlet and the skin of the tube is symmetry. Am I using the right BC? I have Thrust vs RPM data from experiment. I can calculate the induced velocity and pressure jump using momentum theory. I set the P operating as 1 atm. I notice that the P total in inlet should be around 1 atm and at inlet the P static is 1 atm, whereas the P total is unknown. What should I put in gauge pressure column at Pressure inlet and outlet BC? Right now, I keep it 0. It gives me wrong physical characteristics. the velocity is almost uniform everywhere, while the Velocity at oulet (V advance is 0 for hover condition) should be 2x the velocity at the fan surface. I think I have made a mistake....

 October 6, 2007, 08:09 Re: Help with Boundary Conditions #2 jesse Guest   Posts: n/a 1.formula to calculate P total in respective to mach number 2.operating number at inlet set to 0 when not big pressure drop 3.specify the BC at Propell in cell zone Fluid?(i am also not sure about that,cos so far i dealt not too much with propell)

 October 6, 2007, 09:01 Help with Boundary Conditions #3 chun wee Guest   Posts: n/a Hi jesse, Thank for your answer. Isn't that total pressure as M function is for compressible flow? I'm simulating incompressible flow since the velocity is very low. Have you tried similar model before? maybe you can share your experience.

 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 lost.identity CFX 41 May 22, 2013 07:21 Anindya Main CFD Forum 24 January 11, 2012 14:40 NickolasPl OpenFOAM Programming & Development 2 May 19, 2011 05:37 vaina74 Open Source Meshers: Gmsh, Netgen, CGNS, ... 2 May 27, 2010 09:38 michele OpenFOAM Other Meshers: ICEM, Star, Ansys, Pointwise, GridPro, Ansa, ... 2 July 15, 2005 04:15

All times are GMT -4. The time now is 15:58.