outflow boundary condition

Hi All,

first of all “happy new year” to all, folks! Presently I’m doing some simulations, where I compare to results obtained with navier stokes methods using a non-reflecting outlet BC. I was asking myself, if there is a compareable BC implementation in context of LBM? Please, it would be great, if anyone could provide me with some information on various types of outflow BC’s. Since the term “non-reflecting” is pretty new for me, and since I’m not an expert in neither LBM nor BC’s, help is highly appreciated!

Kind Regards,


Hi Fred,

interestingly, this article by Zhaoxia Yang has just been published. Take a look at it (I have not yet), there will be additional references for sure.



Even though my topic of research is LB acoustics, I have so far unfortunately not had the time or the need to look deeply into BCs that are non-reflecting for sound waves. However, I did come across an interesting preprint recently, found here. I have not given it a proper read yet, but it develops a new non-reflecting BC for LB. It also refers to many previous articles on non-reflecting LB BCs. The article that Timm referred to does likewise, so you might want to look into both of these and the articles they refer to.