SIMPLE method problem...

siqma · March 5, 2014, 13:23

I intend to simulate the geometry shown in the figure by simple algorithm to find V U and P in an unsteady system in which current flows from bottom to top. following boundary conditions were used in outlet of the system:
U(:,JN)=U(:,JN-1)
V(:,JN)=V(:,JN-1)
But at some time intervals ,as it can be seen in the figure, there is a fluctuation in velocity(V). After the red line designated in the figure, velocity (V) decreases at different time intervals.
What can be done dealing with this problem???
by the way the program used for simulation is FORTRAN. and this code works for a 2D pipe.

Thanks a million.

siqma · March 7, 2014, 16:35

No body?
I think p boundary conditions at outlet must change to unsteady but I dont know how

March 5, 2014, 13:23	SIMPLE method problem...	#1
siqma New Member Hamed Join Date: Feb 2013 Posts: 7 Rep Power: 13	I intend to simulate the geometry shown in the figure by simple algorithm to find V U and P in an unsteady system in which current flows from bottom to top. following boundary conditions were used in outlet of the system: U(:,JN)=U(:,JN-1) V(:,JN)=V(:,JN-1) But at some time intervals ,as it can be seen in the figure, there is a fluctuation in velocity(V). After the red line designated in the figure, velocity (V) decreases at different time intervals. What can be done dealing with this problem??? by the way the program used for simulation is FORTRAN. and this code works for a 2D pipe. Thanks a million.

March 7, 2014, 16:35	Please Help	#2
siqma New Member Hamed Join Date: Feb 2013 Posts: 7 Rep Power: 13	No body? I think p boundary conditions at outlet must change to unsteady but I dont know how

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