TOWARD A HIGH-ORDER PRESERVING SLIDING-MESH APPROACH FOR COMPUTATIONAL AEROACOUSTICS IN SUBSONIC TURBOMACHINERY

The aeroacoustic analogy is the hybrid technique most used to predict acoustic noise of open rotor turbo-machines. However it is not appropriate to turbo-machines operating in confined spaces- where the diffractions, reflections and near-field flow effects can not be neglected. To overcome this issue, acoustic sources are propagated using linearized Euler equation and rotor motion is taken into account by using a sliding mesh method. This technique allows relative sliding of one grid adjacent to another grid. In addition, we propose a high-order finite volume solver (based on Moving Least Squares approximation MLS), which works on unstructured grid, in order to address most of the industrial applications and their complex geometries. In this paper, two families of MLS-based sliding mesh method are presented. A comparison between the accuracy of the different sliding mesh approaches is made by using a theoretical acoustic benchmark.