Computational strategy for predicting CROR noise at low-speed Part II: investigation of the noise sources computation with the chorochronic approach

摘要

This paper is the second part of a series of three papers dedicated to the prediction of low-speed interaction noise of an isolated Contra-Rotating Open Rotor (CROR). The objective is to investigate the URANS chorochronic approach for computing the unsteady flow across both rotors. The stress is to be put on the correct description and propagation of the wake deficit, which is essential for capturing the unsteady loading onto the rear row and thus the resulting interaction noise. Chorochronic methods are attractive because they require the computation of a single channel only and thus are less costly than full-annulus CFD computations (such as sliding mesh or Chimera techniques). Therefore, the chorochronic technique is used in this study to investigate various mesh topologies. It is shown that the method presents very good agreement with experimental data in absolute levels at a very reasonable cost.