# surface profile

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 July 27, 2011, 02:32 surface profile #1 New Member   navid maroofi Join Date: Jul 2011 Posts: 3 Rep Power: 8 Sponsored Links I am studing about self aeration on open channels with Flow-3d softeware.I want to ask a problem about surface profile. I solve one geometry of slope with 15 degree and q=1m^3/s with ks=.001 with step by step method and run it with flow-3d for this problem but I cant match these result. flow-3d gives much bigger rusult. can anybody help me to find why flow-3d cant give the good result about surface profile? Last edited by navid.maroofi; July 27, 2011 at 03:13.

July 29, 2011, 00:22
#2
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michael barkhudarov
Join Date: Mar 2009
Posts: 332
Rep Power: 11
Quote:
 Originally Posted by navid.maroofi I am studing about self aeration on open channels with Flow-3d softeware.I want to ask a problem about surface profile. I solve one geometry of slope with 15 degree and q=1m^3/s with ks=.001 with step by step method and run it with flow-3d for this problem but I cant match these result. flow-3d gives much bigger rusult. can anybody help me to find why flow-3d cant give the good result about surface profile?
What are the inlet/outlet BC?

 July 29, 2011, 03:34 #3 New Member   navid maroofi Join Date: Jul 2011 Posts: 3 Rep Power: 8 I tried 3 types for inlet Bc. but didnt catch good result yet: 1.specified pressure with height "11.6" (m) with vent that open "0.35" (m) 2.specified velocity, u=2.64 (m/s) & w= -1.093 (m/s) ,h=11.07 3.volume flow rate, q=1 (m^3/s), x flow direction vector=1 , z flow direction vector= -0.2679 and continuative for outlet BC. The geometry has 40 (m) lenghth and 10.72 (m) height-15 degree- The normal depth is near 0.108 m with formula but with flow3d is near 0.2 m.why? Last edited by navid.maroofi; July 29, 2011 at 03:54.

 August 1, 2011, 07:08 #4 Member   Armen A. Ghirghidov Join Date: Mar 2009 Posts: 50 Rep Power: 10 Dear navid maroofi. Try to use outflow BC. BTW 2 and 3 is not quite correct BC. Regards.

August 1, 2011, 09:59
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navid maroofi
Join Date: Jul 2011
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Quote:
 Originally Posted by Ghirghidov Dear navid maroofi. Try to use outflow BC. BTW 2 and 3 is not quite correct BC. Regards.
i used that but no change happend because our flow is supercritical and control from up

 August 2, 2011, 04:06 #6 Member   Armen A. Ghirghidov Join Date: Mar 2009 Posts: 50 Rep Power: 10 Will roughness affect? try to use another mesh. for example number of cells across channel are integer. regards.

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