[cwl]

Hi

I have a simple axisymmetric simulation: cylinder with ends as inlet and outlet - and an additional inlet that is a separated part of side cylinder surface, just a winded rectangle it would be in 3D. No problems converting to 2D, setting Axis boundary condition.

Cylinder has R = 0.25 m and additional inlet has length of l = 0.05 m;
so Inlet Area should be S1=Pi*R^2 and additional inlet area should be S2=2*Pi*R*l; their ratio S1/S2 = 2.5

I'm still confused on how Area is computed in Axisymmetric case: Report (no matter - Sum of Area on surface or Surface Integral of Field Function with Definition set to "1") returns S1 = 3.125E-2 m^2 and S2 = 1.25E-2 m^2.
These values have the same ratio of 2.5.

If i get it right - surface is calculated not for angle of 2*Pi, but for angle of 1 rad.

Has anyone got any ideas of whether i understand thing right and .. why the hell is it 1 rad - not 2*Pi?

[yannaos]

For asysymetrical calculations, effectively, STAR-CCM+ assumes the non-resolved dimension to be 1 rad. (For 2D cases, 1 m).
​I suppose they preferred to strictly use 1 SI (m) or 1 SI derived (rad) u​nit.

[sina_sls]

Originally Posted by cwl

Hi

I have a simple axisymmetric simulation: cylinder with ends as inlet and outlet - and an additional inlet that is a separated part of side cylinder surface, just a winded rectangle it would be in 3D. No problems converting to 2D, setting Axis boundary condition.

Cylinder has R = 0.25 m and additional inlet has length of l = 0.05 m;
so Inlet Area should be S1=Pi*R^2 and additional inlet area should be S2=2*Pi*R*l; their ratio S1/S2 = 2.5

I'm still confused on how Area is computed in Axisymmetric case: Report (no matter - Sum of Area on surface or Surface Integral of Field Function with Definition set to "1") returns S1 = 3.125E-2 m^2 and S2 = 1.25E-2 m^2.
These values have the same ratio of 2.5.

If i get it right - surface is calculated not for angle of 2*Pi, but for angle of 1 rad.

Has anyone got any ideas of whether i understand thing right and .. why the hell is it 1 rad - not 2*Pi?

Hello Chaotic Water,

I want to compute the area in 2D axisymmetric that fluent use for computational , Does it obtain from pi*r^2?

Best Regards,