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-   -   Ship with Impeller BC choosing (https://www.cfd-online.com/Forums/openfoam-solving/154485-ship-impeller-bc-choosing.html)

Daveman945 June 15, 2015 16:41

Ship with Impeller BC choosing
 
Hey guys,
i make my Bachelors degree with this Openfoam case.

There is a boat with in impeller on the bottom side.
Because it would be too complicated and time consuming to simulate the instationary case with the rotating propeller, i consider the alternative to make a circle plane in the impeller cylinder and set a bc on this plane to accelerate the water and twist like a propeller would do.

At the moment i simulate with LTSInterFoam the Boat at a speed prox. 5 m/s without the thrust.

Now i want to implement the thrust, but i dont know how i can make a plane, that
1. lets the water pass through
2. accelerates it like a simplified propeller.

Hope you can help me.

Best regards

Daveman945

Daveman945 June 17, 2015 15:32

I forgot to add the sketch.

http://img4web.com/t/YEBYD.jpg

David

Daveman945 June 21, 2015 06:27

Hello,
i now found the actuationdisksource in the fvOption path.

But the Headerfile doesn´t say too much about the usage.

Is there a tutorial anywhere?

How can i use it with LTSInterFoam?

David

al_th June 23, 2015 10:50

Hi Dave,

I am not sure this will be exactly what you are looking for but my guess is that it is pretty close :

You may want to look at the tutorial "TJunctionFan" ($FOAM_TUTORIALS/incompressible/pimpleFoam/TjunctionFan).
It includes a section of a tube where the BC is of type fan, derived from the cyclic BC that basicall connects two identical patch together.

Using this BC you can represent your thrust by encoding it into a pressure drop between the two sides of the patch, thus accelerating the fluid.

I hope this tutorial can help you achieve what you want.

Best,

Al_th

Daveman945 June 26, 2015 16:25

Okay,
i solved the problem with following settings:

I made a cellzone with cylinderAnnulusToCell.
in this cellzone a made the pressureGradientExplicitSource
then i added a MRFSource to the same Zone.


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