Hi! how far does one should extend the outer boundary in order to simulate real free-stream condition in Fluent, say in simulating flow across airfoils/aircrafts and what would the boundary conditions be? would it be specified as outflow?

thanks in advance!

yin

(1). It is a function of the Mach number. (2). At the transonic speed, the wave and shock wave will extend to a large distance. (3). The mesh independent solution is the basic guideline. Try to extend the outer boundary until the solution around the object is no longer changing vs the boundary location. (4). In case you are not sure of the boundary location, make it very large relative to the object. The larger the better.

Hi

As a general rule of thumb, the domain lenght should be in the at least 30 times larger than the chord length. Out here the imposed BC does not affect the results obtained for the aerofoil.