surface profile

navid.maroofi · July 27, 2011, 03:32

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?

MuxaB · July 29, 2011, 01:22

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?

navid.maroofi · July 29, 2011, 04:34

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?

Ghirghidov · August 1, 2011, 08:08

Dear navid maroofi.

Try to use outflow BC. BTW 2 and 3 is not quite correct BC.

Regards.

navid.maroofi · August 1, 2011, 10:59

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

Ghirghidov · August 2, 2011, 05:06

Will roughness affect?
try to use another mesh. for example number of cells across channel are integer.

regards.

July 27, 2011, 03:32	surface profile	#1
navid.maroofi New Member navid maroofi Join Date: Jul 2011 Posts: 3 Rep Power: 16	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 04:13.

July 29, 2011, 04:34		#3
navid.maroofi New Member navid maroofi Join Date: Jul 2011 Posts: 3 Rep Power: 16	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 04:54.

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August 1, 2011, 08:08		#4
Ghirghidov Member Armen A. Ghirghidov Join Date: Mar 2009 Posts: 50 Rep Power: 18	Dear navid maroofi. Try to use outflow BC. BTW 2 and 3 is not quite correct BC. Regards.

August 2, 2011, 05:06		#6
Ghirghidov Member Armen A. Ghirghidov Join Date: Mar 2009 Posts: 50 Rep Power: 18	Will roughness affect? try to use another mesh. for example number of cells across channel are integer. regards.