# Extrapolation of axisymmetric data

I have results from a 2D axisymmetric simulation and would like to extrapolate this into 3D by rotation around the axis. The filters Rotational Extrusion or VolumeOfRevolution work well for scalar quantities but I can I rotate the velocity field ? The orientation of the initial vectors should change from one radial plane to the other…with for instance the X component transformed into the radial component but I cannot get such a result. Does any of you have experience with this problem ? Thank you in advance,

EJMD

To transform vector data, such as velocity, you might need to use the Python Calculator, although this process can be cumbersome.

For instance, if you have an axisymmetric model on the x-z plane that needs to be rotated around the z-axis and converted into 3D, the vector data for velocity would need to be transformed using the Python Calculator as follows:

from copy import deepcopy
import numpy as np

# Here, the vector array is assumed to be named velocity.
outputArray = deepcopy(velocity)
r = np.sqrt(points[:,0]**2 + points[:,1]**2)
ids = np.where(r>0)

outputArray[ids,0] = velocity[ids,0] * points[ids,0] / r[ids]
outputArray[ids,1] = velocity[ids,0] * points[ids,1] / r[ids]

return outputArray

A simple sample State file is attached below.
axis_sym.zip (53.6 KB)

I hope this is useful to you.

It is very helpful. Thanks a lot.
EJMD