Cloud tracking

jllamas · October 4, 2017, 06:40

Dear all,

I would like to simulate an elbow from Fluent first practice adding particles to the flow.

I want to implement cloud tracking but I do not well understand how to set up the main parameters for it. I have read fluent theory guide about cloud particle tracking but still I do not get succesful results.

With a very low "max number of steps", insufficient to cover the lenght of the model, it works. When I increment the size step it does not. It does not simply finish any DPM iteration.

I would appreciate any ideas and advices to solutionate this problem.

jllamas · October 9, 2017, 06:18

Anybody has an idea about cloud tracking? I am quite lost on this and I would like to learn how to use it.

I would appreciate your help.

obscureed · October 9, 2017, 15:15

I'm afraid I cannot help you much, but perhaps this indicates that you might want to reconsider your choice of model: I have *never* seen cloud tracking used in Fluent DPM (and I have seen many applications of DPM). I would advise normal DPM tracking. You probably want to add Turbulent Dispersion (in the definition of the Injection). If you have enough injection locations and enough Tries in the random walk model, you will get some kind of statistical sample of where the particles go, better than the cloud stuff. Leave the numerics at the defaults, but increase the number of steps so that most particles reach the outlet. If the particles are small and dilute, then they do not affect the flow, so you do not need to activate Interaction with Continuous Phase, and you can track particles without iterating the flow solution.

jllamas · October 10, 2017, 06:55

Dear obscureed,

First of all, thank you very much for your answer. I appreciate it.

I agree with you and most of applications I have also seen are setted up with "Stochastic Tracking", if not say all. However, It has reached to my ears that "Cloud Tracking" could be a better method when turbulent flow and dispersion is presented in the model. With better method I mean that the results obtained are clearer or more defined.

I have used normal DPM tracking several times but I would like to use cloud tracking and make a specific comparison between both methods.

I am using a very basic geometry to start with but the idea is to apply cloud tracking to a more complicated model where combustion is presented.

If someone else wants to contribute with some more additional information about cloud tracking is welcome.

Thanks for your answer obscureed.

October 4, 2017, 06:40	Cloud tracking	#1
jllamas New Member Join Date: Mar 2017 Posts: 4 Rep Power: 9	Dear all, I would like to simulate an elbow from Fluent first practice adding particles to the flow. I want to implement cloud tracking but I do not well understand how to set up the main parameters for it. I have read fluent theory guide about cloud particle tracking but still I do not get succesful results. With a very low "max number of steps", insufficient to cover the lenght of the model, it works. When I increment the size step it does not. It does not simply finish any DPM iteration. I would appreciate any ideas and advices to solutionate this problem.

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October 9, 2017, 06:18		#2
jllamas New Member Join Date: Mar 2017 Posts: 4 Rep Power: 9	Anybody has an idea about cloud tracking? I am quite lost on this and I would like to learn how to use it. I would appreciate your help.

October 9, 2017, 15:15		#3
obscureed Senior Member Join Date: Sep 2017 Posts: 246 Rep Power: 11	I'm afraid I cannot help you much, but perhaps this indicates that you might want to reconsider your choice of model: I have never seen cloud tracking used in Fluent DPM (and I have seen many applications of DPM). I would advise normal DPM tracking. You probably want to add Turbulent Dispersion (in the definition of the Injection). If you have enough injection locations and enough Tries in the random walk model, you will get some kind of statistical sample of where the particles go, better than the cloud stuff. Leave the numerics at the defaults, but increase the number of steps so that most particles reach the outlet. If the particles are small and dilute, then they do not affect the flow, so you do not need to activate Interaction with Continuous Phase, and you can track particles without iterating the flow solution.

October 10, 2017, 06:55		#4
jllamas New Member Join Date: Mar 2017 Posts: 4 Rep Power: 9	Dear obscureed, First of all, thank you very much for your answer. I appreciate it. I agree with you and most of applications I have also seen are setted up with "Stochastic Tracking", if not say all. However, It has reached to my ears that "Cloud Tracking" could be a better method when turbulent flow and dispersion is presented in the model. With better method I mean that the results obtained are clearer or more defined. I have used normal DPM tracking several times but I would like to use cloud tracking and make a specific comparison between both methods. I am using a very basic geometry to start with but the idea is to apply cloud tracking to a more complicated model where combustion is presented. If someone else wants to contribute with some more additional information about cloud tracking is welcome. Thanks for your answer obscureed.