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CFX Piston Motion (CEL)

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Old   October 4, 2005, 20:34
Default CFX Piston Motion (CEL)
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Dante
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Can anybody help me to write down a CEL to define a piston motion with moving grid?
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Old   October 5, 2005, 14:27
Default Re: CFX Piston Motion (CEL)
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Robin
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How about A/2*(1+sin(omega*t)) Assuming your piston starts at the bottom position and A is equal to the sweep distance. Omega should be the frequency in radians per second (i.e. omeaga=2*pi*f, where f is the frequency).

The mesh distortion will be less if you start the piston in the middle position, in which case you should use A/2*sin(omega*t).

Regards, Robin
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Old   October 5, 2005, 19:27
Default Re: CFX Piston Motion (CEL)
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Glenn Horrocks
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Hi,

Actually Robin, for piston motion mesh deformation with the current model available in CFX5 you have to start the piston at top dead centre. You then define the piston motion relative to the TDC position.

If you start anywhere else, when you get to TDC later in the stroke you often get elements turning inside out.

Regards, Glenn Horrocks
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Old   May 28, 2012, 05:40
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Mohammed
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Quote:
Originally Posted by Glenn Horrocks
;73382
Hi,

Actually Robin, for piston motion mesh deformation with the current model available in CFX5 you have to start the piston at top dead centre. You then define the piston motion relative to the TDC position.

If you start anywhere else, when you get to TDC later in the stroke you often get elements turning inside out.

Regards, Glenn Horrocks
please help me in do the motion meshing in a hydrolic cylinder with grade 45 oil
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Old   May 28, 2012, 07:08
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Glenn Horrocks
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Your question is just about exactly the example of how not to ask a question on the forum in the FAQ: http://www.cfd-online.com/Wiki/Ansys...ible_answer.3F
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