[seasoul]

I want to suppress the turbulence in a pre-defined region although i know it is not physically true. In the user guide, it also claims that "one possible approach to define a region in space in which turbulence is suppressed would be to identify an entire region in the volume mesh".

But I cannot find any option in region tree to apply the turbulence suppress to a specific region. I tried to create two physics, one of which with turbulence suppression activated. But in this way, the interface between the turbulence suppressed region and normal region becomes baffle interface (not internal interface any more).

So is this region-based turbulence suppression implementable in StarCCM+? Or It is indeed not region-based but near-wall turbulence suppression?

[ping]

you need to read the user guide again and you will see that you can do exactly what you are asking within a region based on a wall set to be the transition wall - the image in there shows you the cells that are then suppressed

or you can also supress it in a whole region so to use this you need two of more regions which are interfaced to allow flow between them

you can only have one physics continua in regions that transfer flow - a bad error of yours

and of course you could always use the more advanced gamma re theta transition model which predicts where transition occurs rather than you specifying the location in the above approach