In this paper, non-reflecting boundary conditions based on the NSCBC method for three-dimensional compressible viscous flows, especially outlet boundary conditions, are examined and numerical tests for a curved duct flow are made. Using the subsonic non-reflecting outflow boundary conditions, curvature effects for compressible flow are investigated. First, numerical flows in a straight duct was tested for the stability of the solution and the efficiency of the subsonic non-reflecting outflow conditions extended to 3D problems. Numerical tests show that the non-reflecting NSCBC method provides accurate results for very low Reynolds number flow with isothermal no-slip walls. Second, the unsteady Navier-Stokes equations in cylindrical coordinates were numerically solved using the non-reflecting outflow conditions for a curved duct flow with isothermal no-slip walls. The numerical results show the consistency of the solution. Finally, analyzing the curved duct flow results, effects of the duct curvature were studied. A comparison of the numerical results between two curved ducts, the curvature is 102 times larger than smaller one, shows that the maximum intensity of secondary flow appeared at the outlet section of the more curved duct is about 102 times larger.

This content is only available via PDF.
You do not currently have access to this content.