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add mass for floating busddy

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haloo
I am modeling floating budy. the experiments i did I add masss for my floating budy. how could i do that in comsol

Salim

2 Replies Last Post May 5, 2010, 7:11 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago May 4, 2010, 3:42 p.m. EDT
Hi

Well it depends I beleive on the type of modelling you are doing, if its structural + fluidic, you could change the density of the structural part, assuming you have a "body force" or "volumic force" of -G*rho.

If its only fliudic and a cavity, then the body force (as pressure) is still gravity*density which gives you a pressure in the direction of the gravity vector, that you must then decompose with respect to the cavity surface normal to get the correct vector direction and amplitudes as pressure.

Hope this helps
Have fun Comsoling
Ivar
Hi Well it depends I beleive on the type of modelling you are doing, if its structural + fluidic, you could change the density of the structural part, assuming you have a "body force" or "volumic force" of -G*rho. If its only fliudic and a cavity, then the body force (as pressure) is still gravity*density which gives you a pressure in the direction of the gravity vector, that you must then decompose with respect to the cavity surface normal to get the correct vector direction and amplitudes as pressure. Hope this helps Have fun Comsoling Ivar

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Posted: 1 decade ago May 5, 2010, 7:11 a.m. EDT
hi
thanks for your hents , there is another thing my fluid look odd its like jumping every where as in picture i attched. it should not be like that . i am using FSI in MEMS mode.
and another thing any advice to avoid the waves refliction which is comming back after hitting the wall? i did it as out let with velocity=0 but its not working



thanks for u r time

salim
hi thanks for your hents , there is another thing my fluid look odd its like jumping every where as in picture i attched. it should not be like that . i am using FSI in MEMS mode. and another thing any advice to avoid the waves refliction which is comming back after hitting the wall? i did it as out let with velocity=0 but its not working thanks for u r time salim

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