fluent problems

annu · December 12, 2013, 09:02

RodriguezFatz sorry sir now i understand,

the value comes out to be estimated wall distance 5.0e-7.
i had taken fluid as incompressible but fluid releasing flow rate is very high so velocity comes out to be very high.

Zaktatir
sir,installations modeled in your tunnel means?

Zaktatir · December 12, 2013, 13:01

Something in the tunnel

Have you monitored what i asked for yesterday!

annu · December 12, 2013, 13:40

Zaktatir
Sir I had decreased the viscosity value in limits, I thought it would decrease the turbulent viscosity ratio. But viscosity ratio value remains as it is and then inc further.

Zaktatir · December 12, 2013, 13:51

you have to increase it! Then monitor the ratio

annu · December 12, 2013, 13:59

Okay sir, I will do it tomorrow..

Thankyou for the response..

annu · December 12, 2013, 23:59

vicosity ratio now increased to 1.0000e+007 in 348 cells.

Zaktatir · December 13, 2013, 06:15

As i said you have to increase it to very high level and then monitor the ratio because i made several Full Scale simulations and it is normal to get very high levels. When the ratio is constant than that is OK if not we have a problem with setup!

Make this and post us your turbulence specifications and models used!

annu · December 13, 2013, 06:23

viscosity ratio limited to 1.00e007 in352 cell then become constant ..is that okay??

Zaktatir · December 13, 2013, 06:27

.....

You have to monitor the max value of that ratio in your domain

annu · December 13, 2013, 08:20

Okay sir, I will update progress soon ,
you are so kind..

annu · December 14, 2013, 05:30

Zaktatir

sir viscosity ratio value disappear when i increase the limit to avery high value..does it come again or is it vanished finally?

annu · December 15, 2013, 08:41

Zaktatir

i had increased the viscosity limits, it means fluent will not act upto this limit,,means problem is still there??

Zaktatir · December 15, 2013, 10:06

As i said a couple of times you have to monitor the value of the ratio and describe the behavior of it.

annu · December 16, 2013, 23:18

Zaktatir
hi..

sir, turbulent viscosity ratio value is varying.

annu · December 17, 2013, 08:48

help me friends..its really urgent.

pakk · December 17, 2013, 10:10

Zaktatir is giving you some good advice, and is/was really trying to help you.

If your problem is really urgent, I suggest that you read his posts more carefully, so he does not have to ask the same thing several times, that would save a lot of time.

Zaktatir · December 17, 2013, 15:38

How high are the variations please post the outfile of the ratio with good scaling

annu · December 19, 2013, 00:18

turbulent viscosity limited to viscosity ratio of 1.000000e+018 in 34 cells
iter continuity x-velocity y-velocity z-velocity energy k epsilon cl2 time/iter
15186 6.8167e+03 3.3742e-02 2.4911e-02 4.4437e-02 1.4350e-16 2.4341e-03 1.4332e-02 6.2606e-03 0:00:26 9

reversed flow in 349 faces on pressure-outlet 6.

turbulent viscosity limited to viscosity ratio of 1.000000e+018 in 50 cells
15187 6.5498e+03 5.7507e-02 6.0878e-02 6.6267e-02 1.4299e-16 4.9059e-03 1.3393e-02 1.1456e-01 0:00:23 8

reversed flow in 348 faces on pressure-outlet 6.

turbulent viscosity limited to viscosity ratio of 1.000000e+018 in 16 cells
15188 6.3025e+03 4.1791e-02 4.3380e-02 3.6034e-02 1.8478e-16 3.3064e-03 1.2526e-02 4.5538e-02 0:00:21 7

reversed flow in 346 faces on pressure-outlet 6.

turbulent viscosity limited to viscosity ratio of 1.000000e+018 in 8 cells
15189 5.8987e+03 2.3631e-02 1.7922e-02 2.2339e-02 1.9696e-16 5.1657e-03 1.1816e-02 9.5634e-02 0:00:16 6

reversed flow in 345 faces on pressure-outlet 6.

turbulent viscosity limited to viscosity ratio of 1.000000e+018 in 4 cells
15190 5.6010e+03 1.2755e-02 9.1244e-03 1.5703e-02 1.9470e-16 2.5350e-03 1.0967e-02 1.9807e-02 0:00:14 5

reversed flow in 345 faces on pressure-outlet 6.

annu · December 19, 2013, 00:21

hii Zaktatir.

values are not stable, sometimes they disappear and they reappear.

annu · December 23, 2013, 05:22

.........................

December 13, 2013, 08:20		#30
annu Member Join Date: Dec 2013 Posts: 47 Rep Power: 12	Okay sir, I will update progress soon , you are so kind.. Last edited by annu; December 14, 2013 at 05:31.

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December 12, 2013, 09:02		#21
annu Member Join Date: Dec 2013 Posts: 47 Rep Power: 12	RodriguezFatz sorry sir now i understand, the value comes out to be estimated wall distance 5.0e-7. i had taken fluid as incompressible but fluid releasing flow rate is very high so velocity comes out to be very high. Zaktatir sir,installations modeled in your tunnel means?

December 12, 2013, 13:01		#22
Zaktatir Senior Member Join Date: Jan 2010 Location: Germany Posts: 268 Rep Power: 17	Something in the tunnel Have you monitored what i asked for yesterday!

December 12, 2013, 13:40		#23
annu Member Join Date: Dec 2013 Posts: 47 Rep Power: 12	Zaktatir Sir I had decreased the viscosity value in limits, I thought it would decrease the turbulent viscosity ratio. But viscosity ratio value remains as it is and then inc further.

December 12, 2013, 13:51		#24
Zaktatir Senior Member Join Date: Jan 2010 Location: Germany Posts: 268 Rep Power: 17	you have to increase it! Then monitor the ratio

December 12, 2013, 13:59		#25
annu Member Join Date: Dec 2013 Posts: 47 Rep Power: 12	Okay sir, I will do it tomorrow.. Thankyou for the response..

December 12, 2013, 23:59		#26
annu Member Join Date: Dec 2013 Posts: 47 Rep Power: 12	vicosity ratio now increased to 1.0000e+007 in 348 cells.

December 13, 2013, 06:15		#27
Zaktatir Senior Member Join Date: Jan 2010 Location: Germany Posts: 268 Rep Power: 17	As i said you have to increase it to very high level and then monitor the ratio because i made several Full Scale simulations and it is normal to get very high levels. When the ratio is constant than that is OK if not we have a problem with setup! Make this and post us your turbulence specifications and models used!

December 13, 2013, 06:23		#28
annu Member Join Date: Dec 2013 Posts: 47 Rep Power: 12	viscosity ratio limited to 1.00e007 in352 cell then become constant ..is that okay??

December 13, 2013, 06:27		#29
Zaktatir Senior Member Join Date: Jan 2010 Location: Germany Posts: 268 Rep Power: 17	..... You have to monitor the max value of that ratio in your domain

December 14, 2013, 05:30		#31
annu Member Join Date: Dec 2013 Posts: 47 Rep Power: 12	Zaktatir sir viscosity ratio value disappear when i increase the limit to avery high value..does it come again or is it vanished finally?

December 15, 2013, 08:41		#32
annu Member Join Date: Dec 2013 Posts: 47 Rep Power: 12	Zaktatir i had increased the viscosity limits, it means fluent will not act upto this limit,,means problem is still there??

December 15, 2013, 10:06		#33
Zaktatir Senior Member Join Date: Jan 2010 Location: Germany Posts: 268 Rep Power: 17	As i said a couple of times you have to monitor the value of the ratio and describe the behavior of it.

December 16, 2013, 23:18		#34
annu Member Join Date: Dec 2013 Posts: 47 Rep Power: 12	Zaktatir hi.. sir, turbulent viscosity ratio value is varying.

December 17, 2013, 08:48		#35
annu Member Join Date: Dec 2013 Posts: 47 Rep Power: 12	help me friends..its really urgent.

December 17, 2013, 10:10		#36
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 26	Zaktatir is giving you some good advice, and is/was really trying to help you. If your problem is really urgent, I suggest that you read his posts more carefully, so he does not have to ask the same thing several times, that would save a lot of time.

December 17, 2013, 15:38		#37
Zaktatir Senior Member Join Date: Jan 2010 Location: Germany Posts: 268 Rep Power: 17	How high are the variations please post the outfile of the ratio with good scaling

December 19, 2013, 00:18		#38
annu Member Join Date: Dec 2013 Posts: 47 Rep Power: 12	turbulent viscosity limited to viscosity ratio of 1.000000e+018 in 34 cells iter continuity x-velocity y-velocity z-velocity energy k epsilon cl2 time/iter 15186 6.8167e+03 3.3742e-02 2.4911e-02 4.4437e-02 1.4350e-16 2.4341e-03 1.4332e-02 6.2606e-03 0:00:26 9 reversed flow in 349 faces on pressure-outlet 6. turbulent viscosity limited to viscosity ratio of 1.000000e+018 in 50 cells 15187 6.5498e+03 5.7507e-02 6.0878e-02 6.6267e-02 1.4299e-16 4.9059e-03 1.3393e-02 1.1456e-01 0:00:23 8 reversed flow in 348 faces on pressure-outlet 6. turbulent viscosity limited to viscosity ratio of 1.000000e+018 in 16 cells 15188 6.3025e+03 4.1791e-02 4.3380e-02 3.6034e-02 1.8478e-16 3.3064e-03 1.2526e-02 4.5538e-02 0:00:21 7 reversed flow in 346 faces on pressure-outlet 6. turbulent viscosity limited to viscosity ratio of 1.000000e+018 in 8 cells 15189 5.8987e+03 2.3631e-02 1.7922e-02 2.2339e-02 1.9696e-16 5.1657e-03 1.1816e-02 9.5634e-02 0:00:16 6 reversed flow in 345 faces on pressure-outlet 6. turbulent viscosity limited to viscosity ratio of 1.000000e+018 in 4 cells 15190 5.6010e+03 1.2755e-02 9.1244e-03 1.5703e-02 1.9470e-16 2.5350e-03 1.0967e-02 1.9807e-02 0:00:14 5 reversed flow in 345 faces on pressure-outlet 6.

December 19, 2013, 00:21		#39
annu Member Join Date: Dec 2013 Posts: 47 Rep Power: 12	hii Zaktatir. values are not stable, sometimes they disappear and they reappear.

December 23, 2013, 05:22		#40
annu Member Join Date: Dec 2013 Posts: 47 Rep Power: 12	.........................