wall roughness
 

for wall roughness E 9.8 is used for smooth wall. For rough wall what value should E have ?

i was wondering if you ever found a solution to the E value?

im trying to understand the parameters set for the wall functions, but i have been struggling to find out the exact meaning of E and the sorta values it requires

im aware that E=9.8 is the standard value in the source code

thanks