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Natural convection in enclosure with heat generating source

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Old   February 2, 2017, 04:03
Default Natural convection in enclosure with heat generating source
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Swapnil P
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Facing big confusion regarding understanding of the flow in enclosure with heat generating strip at the middle.

The strip is placed in the middle of the square enclosure and generating uniform heat. The top and bottom walls are adiabatic and vertical side walls are isothermal at ambient temperature. The temperature profile and velocity profile is similar on both side of the strip but how come the intensity of the contours (stream function) is different on both sides of strip?

For reference providing the stream function, isotherms and velocity magnitude profile.
Attached Images
File Type: jpg Stream Function.jpg (99.0 KB, 16 views)
File Type: jpg Temp. Profile.jpg (88.7 KB, 13 views)
File Type: jpg Velocity Vector magnitude.jpg (150.0 KB, 12 views)
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Old   February 2, 2017, 04:34
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The solution seems reasonable, is steady (very low Re number?) and symmetric, the temperature field show a stratification. What is strange is that you do not have zero velocity at walls
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Old   February 2, 2017, 04:43
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Quote:
Originally Posted by FMDenaro View Post
The solution seems reasonable, is steady (very low Re number?) and symmetric, the temperature field show a stratification. What is strange is that you do not have zero velocity at walls
Yes its steady state natural convection problem with high Rayleigh number 10^9. Also, the amount of heat generation is very low as compare to the length of the geometry.
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Old   February 2, 2017, 04:55
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Quote:
Originally Posted by nuclear_swapnil View Post
Yes its steady state natural convection problem with high Rayleigh number 10^9. Also, the amount of heat generation is very low as compare to the length of the geometry.

and the velocity at the walls??
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Old   February 2, 2017, 05:10
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Quote:
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and the velocity at the walls??
At the wall velocity is zero. I have scaled up the vectors for better view therefore it shows flow at the wall but actually it is near the wall.
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Old   February 2, 2017, 05:26
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Ok, then I don't see problems in the solution...just consider to do the grid refinement study to assess convergence of the solution
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Old   February 2, 2017, 06:36
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Ok, then I don't see problems in the solution...just consider to do the grid refinement study to assess convergence of the solution
Actually, there is no problem in the solution but the understanding of the stream function in the enclosure, which is not uniform inside the enclosure. If you check the stream function contours, it is more intense on one side of the heat generating strip as compare to other side. How come this is possible?
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Old   February 2, 2017, 06:44
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could you plot the contour lines instead of the shaded contour? I suggest to superimpose the streamline contours to the vector plot....when two streamlines are close, the velocity is greater than when they are more far..
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ansys fluent, fluid flow, heat transfer, natural convection, stream function

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