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kiran August 10, 2004 04:09

problem in plotting cl curve
Hi users,

I am calculating the lift force on the fins of a ship.It consists of two fins on either sides of the hull. i want to calculate the lift force on both the fins. When i gave monitor force for both the fins the one that was given last was monitored. could anyone please suggest how to get cl value for both the fins in a single job.

Ajay August 10, 2004 17:48

Re: problem in plotting cl curve
You could use two seperate windows to monitor each.

kiran August 11, 2004 00:49

Re: problem in plotting cl curve
Thanks ajay for the reply.But i find that fluent is only taking one cl monitoring input . i gave monitoring command on separate windows it only monitored one,the one that was given last was only monitored.

shang August 11, 2004 03:41

Re: problem in plotting cl curve
I'm also puzzled with this problem

George August 11, 2004 08:57

Re: problem in plotting cl curve
I think I met with this problem in another for some time ago. It is probably an error in FLUENT - in case you don't find logical explanation for this behaviour, it must be so. Please report the error on FLUENT technical support web pages.

Good luck


Jason August 11, 2004 11:04

Re: problem in plotting cl curve
Currently, you're only able to use one monitor for the drag forces and one monitor for the lift forces.

There's a couple options though. If you're not monitoring any drag forces, then you can use the drag monitor to watch the lift of the second fin. Make the lift monitor watch fin 1, then make the drag monitor watch fin 2. You have to update the force vector for the drag monitor to be in the same direction as the force vector in the lift monitor. Only use this if you're not monitoring any drag forces and the lift forces are of radically different magnitudes.

The easier option, which works well if the lift forces have approximately the same magnitude is to turn on the "per zone" option in the force monitors panel. Then you can select both fins to monitor, and it will plot two lines on the same graph... one for each fin, and they will be labeled, so don't worry about that. If the difference in the forces is too high, then variation in the forces during the iteration process might be smaller then the resolution of the plot. Just something to watch out for.

Hope this helps. Jason

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