Symmetry vs Free-slip wall in open sea condition
 

Hi all,

I am currently simulating a turbine farm with dimensions 30 (depth)* 125 (width) * 280 (length). There are 3 turbine (diameter=20) in a row. This farm is a part of an open sea.
What is the difference between symmetry and free-slip condition for outer walls in such a domain (it is worth mentioning that there is no free surface in this simulation and all six sides are treated the same) ? I heard from an expert that these two BCs in current farm does not make significant difference. Please explain it more for me.

King Regards,
Soheil