Jason Huang


Thanks for your reply. For the material properties of the left domain, the absorption and scattering coefficient is 0, and the refractive index is 1. Is this the correct setting for the air?

 The strange thing is the attenuation disappears when I set the boundary condition of the front and back surfaces to symmetry(the previous figure is the front view). However, I want to set these two surfaces as pressure outlets instead of symmetry. Is there any other possible reason that led to this error?