[PCFD]

Hi,

I am currently writing a small tool which helps me to set up blade geometries in a turbomachine.
In order to define the blade camberlines, I am using either a m' / theta (m' = m_prime) or a m/r*theta (m = meridional coordinate) coordinate system. I found both definitions in the handbook of Mises (Drela).

Now, I am asking myself which coordinate system is more senseful. I know that some "comercial" tools prefer the m'/theta-definition because it shell be angle-preserving - but why is this not the case with m/r*theta? Can this be proven mathematically?

Is the m'/theta coordinate-system senseful if the fluid is _not_ following a streamline (e.g. in a deswirler which turns the flow from radial to axial), as described in the mises manual?

Thx for the help.