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Use the results of a study as model input in another study.
Posted 22 set 2016, 16:35 GMT-4 Heat Transfer Version 5.2 2 Replies
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Hello!
I am trying simulate how the thermal state of a bubbling fluid evolves over time. To do so I am trying to run a stationary simulation using Comsol's Turbulent Bubbly Flow module and then use the results of that study, namely the liquid's motion, in a time dependent simulation using Comsol's Heat Transfer i Fluids module.
The first simulation runs well and gives the expected results, however I have not been able to use the results of that study as model input in my time dependent simulation. In the settings of the Heat Transfer in Fluids module I specify that the Velocity field should be the results from the first study, yet Comsol seems to run the simulation with no motion what so ever in the fluid.
I have also tried to use a User defined Velocity field, by exporting the result of the first study as data, and then creating a interpolating function which I use to define the Velocity field. I did not get that to work either.
I assume that using the results of one simulation as model input to another must be a common technique, yet I have found very little information on how to do so. Is there anyone who have done this that could point me in the right direction? Or in the direction of resources I could use to figure it out?
Thanks in advance.
Edit: I have attached my project in case anyone wants to take a look.
I am trying simulate how the thermal state of a bubbling fluid evolves over time. To do so I am trying to run a stationary simulation using Comsol's Turbulent Bubbly Flow module and then use the results of that study, namely the liquid's motion, in a time dependent simulation using Comsol's Heat Transfer i Fluids module.
The first simulation runs well and gives the expected results, however I have not been able to use the results of that study as model input in my time dependent simulation. In the settings of the Heat Transfer in Fluids module I specify that the Velocity field should be the results from the first study, yet Comsol seems to run the simulation with no motion what so ever in the fluid.
I have also tried to use a User defined Velocity field, by exporting the result of the first study as data, and then creating a interpolating function which I use to define the Velocity field. I did not get that to work either.
I assume that using the results of one simulation as model input to another must be a common technique, yet I have found very little information on how to do so. Is there anyone who have done this that could point me in the right direction? Or in the direction of resources I could use to figure it out?
Thanks in advance.
Edit: I have attached my project in case anyone wants to take a look.
Attachments:
2 Replies Last Post 24 set 2016, 06:22 GMT-4
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Posted:
8 years ago
When you tell the Heat Transfer interface to use the Bubbly Flow velocity field, what that means is that, during computation, the flow fields will be coupled. It has nothing to do with initial conditions.
What you need is to go into Study 2/Step 1. In the Settings window go to Values of Dependent Variables. For the second option, "Values of variables not solved for," you want the following settings:
Settings: User controlled
Method: Solution
Study: Study 1, Stationary
Selection: Automatic
Keep in mind that this will be very fast, but will not adjust the flow based on the heat transfer. If this is acceptable (assuming the effect of natural convection is minimal compared with the flow itself) you can just use the fully developed flow field without modification. If you want to allow the flow to react to the heat input, enable Turbulent Bubbly Flow in Study 2 and set "Initial values of variables solved for" to the same settings as you did above. I think everything should work at that point, but be sure to double check your results, as always.
Since I'm a relative newbie at COMSOL it would be nice if someone with more experience can confirm there's nothing I missed.
What you need is to go into Study 2/Step 1. In the Settings window go to Values of Dependent Variables. For the second option, "Values of variables not solved for," you want the following settings:
Settings: User controlled
Method: Solution
Study: Study 1, Stationary
Selection: Automatic
Keep in mind that this will be very fast, but will not adjust the flow based on the heat transfer. If this is acceptable (assuming the effect of natural convection is minimal compared with the flow itself) you can just use the fully developed flow field without modification. If you want to allow the flow to react to the heat input, enable Turbulent Bubbly Flow in Study 2 and set "Initial values of variables solved for" to the same settings as you did above. I think everything should work at that point, but be sure to double check your results, as always.
Since I'm a relative newbie at COMSOL it would be nice if someone with more experience can confirm there's nothing I missed.
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Posted:
8 years ago
Thank you Justin. It worked and the simulation runs as expected. You have saved me from a lot of frustration. Thanks again, I hope you enjoy your weekend!