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 purushotam85 April 16, 2013 13:22

Calculating volume of 3D object from its co-ordinates

Dear Friends,

I am working on geometric reconstruction method for volume of fluid method. It is a 3D code. For this i need to evaluate the volume created by intersection of a cell (cube or cuboid) and a plane (may not be aligned with cell faces). I can calculate all the points of the geometry created by the intersection and store in (x,y,z) array but I do not know how to evaluate the volume of the entity.

It would be great help if you can suggest me of any existing idea or literature.

Sincerely,
Purushotam

 FMDenaro April 16, 2013 18:02

Quote:
 Originally Posted by purushotam85 (Post 421012) Dear Friends, I am working on geometric reconstruction method for volume of fluid method. It is a 3D code. For this i need to evaluate the volume created by intersection of a cell (cube or cuboid) and a plane (may not be aligned with cell faces). I can calculate all the points of the geometry created by the intersection and store in (x,y,z) array but I do not know how to evaluate the volume of the entity. It would be great help if you can suggest me of any existing idea or literature. Sincerely, Purushotam
if you can subdivide your object in tethraedron (Lagrangian simplex) then you can compute volume from the four-node obiect by means of a simple formula you find in books on Finite Element.

 ztdep April 16, 2013 20:29

The volume of any volume in3D can be calculated with Gauss theorem.

int(divergence(xi))dV=int(xc*Sx)dS=sigma (xc*Sx)

that means the volume can be calcualted as the sum of (face center x coordinate multiply the surface vector x component)

 sbaffini April 18, 2013 07:25

Once you have all the points of the surface you can triangulate it and use the following (already discussed by someone above):

http://www.public.iastate.edu/~zjw/p...1999-AIAAJ.pdf

In general, however, you should check some VOF literature to know if there are some specific issues to consider when applying this with VOF.

 ok___ko April 18, 2013 08:14

hi, do you know how to creat a geometry and could change the length in different conditions.

 Ahmed April 18, 2013 11:34

Guys
It is much more simpler
It is the scaler tripple product of your linear algebra text book
Good Luck

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