Convergence - Mixed Convection - Circular Cylinder

Aarthy Meena · May 30, 2016, 05:51

Hello Everyone,

I am trying to model, mixed convection heat transfer around a circular cylinder using FLUENT.

Following are the details of my setup:
1) Polar co-ordinate system.
2) The Cylinder of diameter 1m is placed at the origin and the boundaries are placed 150m away form the cylinder surface.
3) The Reynolds number is 40 and Richardson number is 4.
4) Corresponding inlet velocity is 0.000584293 m/s and the gravity is -8.1935e-05 m/s2.
5)Boussinesq approximation.

Problem
The solution is not at all converging. (Reversed flow at x faces at pressure-outlet).

I have already tried
1) Changing the outlet boundary to outflow.
2) Moving the boundary far away from cylinder (I tried even upto 1000m).
3) Using PISO, PRESTO methods.
4) Gradually increasing the Ri value.
5) Unsteady solution.
6) Reducing URF values

Kindly please help me solve this. THANK YOU.

Far · August 16, 2016, 13:31

did you solve your problem?

May 30, 2016, 05:51	Convergence - Mixed Convection - Circular Cylinder	#1
Aarthy Meena New Member Aarthy Meena Join Date: Oct 2015 Location: Trichy Posts: 29 Rep Power: 11	Hello Everyone, I am trying to model, mixed convection heat transfer around a circular cylinder using FLUENT. Following are the details of my setup: 1) Polar co-ordinate system. 2) The Cylinder of diameter 1m is placed at the origin and the boundaries are placed 150m away form the cylinder surface. 3) The Reynolds number is 40 and Richardson number is 4. 4) Corresponding inlet velocity is 0.000584293 m/s and the gravity is -8.1935e-05 m/s2. 5)Boussinesq approximation. Problem The solution is not at all converging. (Reversed flow at x faces at pressure-outlet). I have already tried 1) Changing the outlet boundary to outflow. 2) Moving the boundary far away from cylinder (I tried even upto 1000m). 3) Using PISO, PRESTO methods. 4) Gradually increasing the Ri value. 5) Unsteady solution. 6) Reducing URF values Kindly please help me solve this. THANK YOU. __________________ Aarthy, PG Student, National Institute of Technology, Trichy, India.

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August 16, 2016, 13:31		#2
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	did you solve your problem?