Contra-Rotating Open Rotor (CROR) aircraft engines, among others, have been the subject of extensive investigation, as a cause of their increased propulsive efficiency. Due to their unducted fan architecture CROR noise emissions are an issue that needs to be addressed. In the present study, tonal directivity patterns of CROR aircraft engines were investigated and results derived from a computational approach were processed and compared to experimental measurements. The two cases under investigation consisted of tone noise level extractions for similar engine configurations. Both, rotor-alone and interaction tones were accounted for. The final display of computational directivity patterns showed great resemblance to the experimental measurements, despite some slight divergence of the case specifications, thus providing useful conclusions regarding the overall trend of tone noise. This study may thus provide validation for the original numerical model and procedure, while encouraging future research on CROR tone noise directivities.
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