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Simulation of rotating undershot water wheel

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Old   April 22, 2015, 23:00
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Glenn Horrocks
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There are several problems with the mesh you show:

* I assume you want to model the river with a free surface. In that case you need to mesh a region of air above the river level as well.
* You do not mesh the impeller. This is such a common mistake recently that it would be good if somebody wrote an FAQ about it.
* You model the fluid region around the impeller with the impeller as a cut out region inside the domain. have a look at how the rotating machinery is modelled in the tutorials.
* You put the domain around the impeller in a cylindrical domain and set it to be a rotating frame of reference, and connect this domain to the surroundings with a GGI interface
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Old   April 24, 2015, 02:57
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Miss Anna
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Thank you very much for your comment.
I have made new setup for this simulation by considering your comment. But, this time i use boolean operation to eliminate the water wheel structure. Besides that, I have include the air domain in the analysis to take account the air region in the river. Is it correct if I just eliminate the water wheel just like the picture attached. How can I apply the rotating frame of reference here?
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Old   April 24, 2015, 05:50
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As a rotating frame of reference domain should be cylindrical, you will need to put the impeller in a cylindrical cut out region. You then connect the stationary outer domain to the cylindrical inner domain with a GGI with a frame change condition.
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Old   April 26, 2015, 12:59
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Miss Anna
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Thank you very much for your reply.

Oh I see. So, I have to make a rotating domain in the form of cylindrical right?

I have improved my setup based on your comment. But, when I runned the simulation, it produced no result. I have keep searching where the possible cause of the error. But, I still have no idea why it happened.
Do you have any idea of this problem?

Thank you.
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Old   April 26, 2015, 19:35
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The error message is very clear - it failed to interpolate an initial condition onto this mesh.
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Old   June 7, 2016, 23:24
Default Simulation of rotating undershot waterwheel
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Ana Fadilah
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Hi Everyone.

I am also working on simulation of water wheel in open channel flow. I am using Ansys CFX and using multiphase model which includes water and air as the working fluid.

I setting different inlet for both fluid. For water inlet, I set the velocity 0.03 m/s while for air inlet, I set the velocity to 0 m/s.

For outlet, I set the BC to static pressure with 0 relative pressure.
I attached the figure of my result here.

I am confusing why the water volume fraction is becoming like this. I dont have idea why the flow of water are becoming like this especially at the outlet.

And, Is it possible for the torque to be negative?

Thank you. Best regards.
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