# Streamlines at the boundary of rotating and stationary domains are malformed

I am simulating a turbine and have divided the mesh into domains: the piping before and after the blade and the turbine blades. The domain containing the blades rotates at 2000 rpm while the other domains are stationary.

The mesh is structure and the mesh (between the domains) is conformal.

The turbine I am simulating is an axial-flow Wells turbine. The solution is steady state. This turbine has 8 blades (360 / 8 = 45° angle between blades). Due to the circumferential symmetry, only one-eighth of the annulus has been computed, imposing periodic boundary conditions in the tangential direction. In my model, the computational domain has been restricted in the axial direction to four chord lengths upstream and eight chord lengths downstream of the blade. Blades are symmetry (Naca00XX).

The computational domain is as follows:

According the following figures,

I want to obtain streamlines as in the following image from Insight analysis of biplane Wells turbine performance (Fig. 7):

Shaaban, S., & Hafiz, A. A. (2012). Effect of duct geometry on Wells turbine performance. Energy Conversion and Management, 61, 51-58.

• It seems like a setup fault, at first sight. Is this your first time running a turbine blade with periodic bc? Mar 20, 2016 at 12:52
• This is converged solution. And also, This turbine have rotational periodic bc. Please see more explanation in above question. Mar 22, 2016 at 9:38
• The gradients are right at the mesh interfaces, as far as I see from the images. There might be some numerical (mesh) problems. I'm not a CFD guy (anymore) so this is the limit of my thoughts. Btw, this is a nicely posted question. Good luck. Mar 22, 2016 at 18:22