Flow promoter meshing
 

Hello everyone ,
I have been trying to learn meshing lately and while doing so , I came across a problem in my research. This is a microchannel with some flow promoters that I have been trying to mesh. So far I have tried to apply multizone meshing and edge sizing. I also tried to use inflation without multizone , however the quality of the mesh decreases badly . I was wondering if I am missing something here. I have been unable to mesh in either of the methods used. Note the top wall is a plane wall and no vortex generators have been used there