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Neutral condition

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Hi all

can someone explain to me the meaning of the "neutral condition" of the velocity, and what is the difference between this condition and "no slip" condition ?

thank you

3 Replies Last Post 09.11.2011, 03:56 GMT-5
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 07.11.2011, 10:58 GMT-5
Hi

I belive you should be slightly more specific, if you want a reply, ie. physics, BC case, something about your model, or ?

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Good luck
Ivar
Hi I belive you should be slightly more specific, if you want a reply, ie. physics, BC case, something about your model, or ? -- Good luck Ivar

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Posted: 1 decade ago 08.11.2011, 03:22 GMT-5
Hi Ivar,

thank you for the reply, i'm using "convection conduction" and "Navier stokes equations" to simulate natural convection due to one heated plate, my domain is a rectangle, i want to know which condition for the "navier stokes equation" must i impose on the heated plate boundary ? neutral or no slip ? what is the difference between this two boundaries ?
Hi Ivar, thank you for the reply, i'm using "convection conduction" and "Navier stokes equations" to simulate natural convection due to one heated plate, my domain is a rectangle, i want to know which condition for the "navier stokes equation" must i impose on the heated plate boundary ? neutral or no slip ? what is the difference between this two boundaries ?

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 09.11.2011, 03:56 GMT-5
Hi

I'm not following you, because in my v4.2a I cannot identify the BC you are referring to (probably you are in an older version and the naming has changed. Again it depends on the physics and model you have, normally a fluid is sticking to the wall so no-slip is the "natural one" with zero velocity at the border. But that depends somewhat on the fluid and the wall properties (and the scale of phenomena you are studying)

--
Good luck
Ivar
Hi I'm not following you, because in my v4.2a I cannot identify the BC you are referring to (probably you are in an older version and the naming has changed. Again it depends on the physics and model you have, normally a fluid is sticking to the wall so no-slip is the "natural one" with zero velocity at the border. But that depends somewhat on the fluid and the wall properties (and the scale of phenomena you are studying) -- Good luck Ivar

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