no velocity drop throughout the flow - LES

ssa_cfd · November 20, 2018, 07:49

Hi all,

I am doing a flow inside a room (x=0.8m length, z=0.4m height, y=0.4m width) with an inlet velocity of 0.225 m/s coming inside the domain through a small window like opening from the top. The simulation was done in LES - dynamickEqn. I did velocity probe at different points along the length of domain and found that there is a very little change in the velocity.
See attached figure. Any idea why it happens..? I have tested it with different boundary conditions and different schemes, but the results remain the same.

Thanks..!

RobertHB · November 21, 2018, 03:51

I guess you are looking for turbulences in your flow. Is it possible that 30s is not enough to devellop the flow and as such you dont see velocity fluctuations?

ssa_cfd · November 21, 2018, 03:59

Hi Robert,

The simulation is lagrangian. So after sometime particles are inserted and I have done the simulation for 1800 seconds. There is no change in the velocity probe after 30 seconds. That is the problem. It is not fluctuating and not reducing throughout the length of the domain.

Thanks.
ssa

November 21, 2018, 03:51		#2
RobertHB Senior Member Robert Join Date: May 2015 Location: Bremen, GER Posts: 292 Rep Power: 12	I guess you are looking for turbulences in your flow. Is it possible that 30s is not enough to devellop the flow and as such you dont see velocity fluctuations? __________________ If you liked my answer to your question, please consider leaving a "Like" in return

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November 21, 2018, 03:59		#3
ssa_cfd Member ssa Join Date: Sep 2018 Posts: 93 Rep Power: 7	Hi Robert, The simulation is lagrangian. So after sometime particles are inserted and I have done the simulation for 1800 seconds. There is no change in the velocity probe after 30 seconds. That is the problem. It is not fluctuating and not reducing throughout the length of the domain. Thanks. ssa