To create a circular plane via a field function, follow these steps:
Define a local coordinate system at the desired location of the circular plane. In this article, the coordinate system is defined through parameters with the y-direction as the plane normal and named CircleSystem (see images 1a and 1b for the parameters and coordinate system, where the pi parameter is obtained with acos(-1)).
a) b)
Figure 1: a) Parameters used to define field functions and coordinate location, b) Local coordinate system
Create a scalar field function with the following form:
if x^2 + z^2 < r^2, Value = 1, else Value = 0
This can be written in Simcenter STAR-CCM+ syntax as:
(pow($$Position(@CoordinateSystem("CircleSystem"))[0],2)+pow($$Position(@CoordinateSystem("CircleSystem"))[2],2) < pow(${Radius},2)) ? 1 : 0
Create a plane section at the desired location and create a threshold with the plane section as input using the field function created above. Setting the threshold above 0.5 will give you the circle, and setting a value lower than 0.5 will give you the outside of the circle. See the pictures below.
a) b)
Figure 2: a) Plane with threshold value above 0.5, b) Plane with threshold value below 0.5
The image below visualizes the z-position on the newly created circular plane. The resolution of the plane will be governed by the underlying mesh, so refining the mesh will give a smoother plane. See the area of the plane in the annotation.
Figure 3: Resolution of the derived circular part depending on the underlying mesh size. 1 - coarse, 2 - medium, 3 - fine.
There is an attached sim file made in Simcenter STAR-CCM+ 2210, to view the methodology.