Sail's 2D Section Drag & Surface Roughness

Hi,
Probably a rookie question for CFD specialists:
For instance I wonder what would be the difference in 2D section drag between
1- Moth luff pocket sail with all the sewings of the actual sail
2- A Virtual sistership sail, but with "perfect" surface roughness, similar to monofilm sail fabric for instance.
I have been investigating TurbulentBoundary Layers/ Turbulent Kinetic Dissipation/ among others, but could not find any workpapers adressing the "Surface Roughness" in the context of Turbulent Boundary Layers.
Thanks in advance for your "enlightments"
Regards
E

 

A first source is always Hoerner's Fluid Dynamic Drag:
https://ia600707.us.archive.org/13/...65/Fluid-dynamic_drag__Hoerner__1965_text.pdf
Chapter V

 

Thank You so much Remmlinger,
Ironicaly I have the Hoerner's Fluid Dynamic Lift book, and I thought it was "The Hoerner's".
So now, I have two 500 pages fluid dynamic books, as a result, rainning sundays will not be boring days anymore.
Thank you again, and continue to post your great research, with Mikka's posts your are my prefered BDN 's reading.
From Manfred Curry to Hoerner via Horten brothers, it seems you have some well established traditions, in addition to Oktober Fest.
Fair wind and thank you again
Best Regards
Erwan