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navid.maroofi July 27, 2011 02:32

surface profile
 
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 00:22

Quote:

Originally Posted by navid.maroofi (Post 317646)
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 03:34

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 07:08

Dear navid maroofi.

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

Regards.

navid.maroofi August 1, 2011 09:59

Quote:

Originally Posted by Ghirghidov (Post 318293)
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 04:06

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

regards.


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