[zcheng]

Hello everyone,

Does anyone knows how to put cube root in OpenFOAM?

[clapointe]

Yes, this is quite straightforward. Knowing that we can calculate the square root of something e.g. x with :

sqrtX = sqrt(x)

we might guess that foam would use similar abbreviation for the cube root. So we guess that cbrt is likely and search the code for "cbrt" and see many matches. You could try computing a cube root of x as :

cbrtX = cbrt(x)

I've not used this myself before, so be sure to make sure it does what we expect. Another straightforward option that I use sometimes is the pow function :

cbrtX = pow(x,1.0/3.0)

Caelan

[zcheng]

Thanks a lot!

[anon_q]

For a more safe result (including negative numbers) you can use the following:

 // calculate the cube root of abs(x)
cbrtAbsX = pow(abs(x), 1.0/3.0)
 // the cube root is returned according to the sign of x
cbrtX = (x < 0)? -cbrtAbsX:cbrtAbsX

[zcheng]

Thanks for the suggestion!