Improved block interface conditions for aeroacoustic problems with grid discontinuities

Aeroacoustic simulations are extremely sensitive to numerical errors. To achieve a high order of accuracy, optimized finite difference schemes, such as the wellknown dispersionrelationpreservation schemes, and multiblock structured meshes are often used. Challenges appear in communicating the flow information near grid discontinuities between neighboring blocks, and sophisticated interface treatments are required. The characteristic interface condition has been successful in applications in previous publications, and yet limitations exist that are identified in the present study. This paper proposes a new interface treatment based on the analogy between finite difference and finite volume discretizations. Onesided finite difference schemes are used to calculate the spatial derivatives in the normal direction, and the residuals are reconstructed from a finite volume perspective. Applications to several benchmark cases show an encouraging improvement as compared to the previous characteristic interface treatments.