NASA LogoNTRSNTRS - NASA Technical Reports ServerSearchmore_vertCollectionsAboutNewsHelpLogin Back to ResultsUnified aeroacoustics analysis for high speed turboprop aerodynamics and noise. Volume 3: Application of theory for blade loading, wakes, noise, and wing shieldingResults of the program for the generation of a computer prediction code for noise of advanced single rotation, turboprops (prop-fans) such as the SR3 model are presented. The code is based on a linearized theory developed at Hamilton Standard in which aerodynamics and acoustics are treated as a unified process. Both steady and unsteady blade loading are treated. Capabilities include prediction of steady airload distributions and associated aerodynamic performance, unsteady blade pressure response to gust interaction or blade vibration, noise fields associated with thickness and steady and unsteady loading, and wake velocity fields associated with steady loading. The code was developed on the Hamilton Standard IBM computer and has now been installed on the Cray XMP at NASA-Lewis. The work had its genesis in the frequency domain acoustic theory developed at Hamilton Standard in the late 1970s. It was found that the method used for near field noise predictions could be adapted as a lifting surface theory for aerodynamic work via the pressure potential technique that was used for both wings and ducted turbomachinery. In the first realization of the theory for propellers, the blade loading was represented in a quasi-vortex lattice form. This was upgraded to true lifting surface loading. Originally, it was believed that a purely linear approach for both aerodynamics and noise would be adequate. However, two sources of nonlinearity in the steady aerodynamics became apparent and were found to be a significant factor at takeoff conditions. The first is related to the fact that the steady axial induced velocity may be of the same order of magnitude as the flight speed and the second is the formation of leading edge vortices which increases lift and redistribute loading. Discovery and properties of prop-fan leading edge vortices were reported in two papers. The Unified AeroAcoustic Program (UAAP) capabilites are demonstrated and the theory verified by comparison with the predictions with data from tests at NASA-Lewis. Steady aerodyanmic performance, unsteady blade loading, wakes, noise, and wing and boundary layer shielding are examined.Document ID19910014537Acquisition SourceLegacy CDMSDocument TypeContractor Report (CR)AuthorsHanson, D. B.*(Hamilton Standard Windsor Locks, CT, United States)*Mccolgan, C. J.*(Hamilton Standard Windsor Locks, CT, United States)*Ladden, R. M.*(Hamilton Standard Windsor Locks, CT, United States)*Klatte, R. J.*(Hamilton Standard Windsor Locks, CT, United States)*Date AcquiredSeptember 6, 2013Publication DateMay 1, 1991Subject CategoryAcousticsReport/Patent NumberNAS 1.26:185193NASA-CR-185193Accession Number91N23850Funding Number(s)PROJECT: RTOP 535-03-01CONTRACT_GRANT: NAS3-23720Distribution LimitsPublicCopyrightWork of the US Gov. Public Use Permitted.Available DownloadsNameType19910014537.pdfSTIcloud_downloadcontent_copyvisibilityRelated RecordsThere are no records associated with this record.visibility_offNo Preview Available
 No Fear Act | Freedom of Information Act | Office of the Inspector General | Agency Financial ReportsNASA Web Privacy Policy and Important Notices | NASA Guidelines for Quality of InformationDisclaimers, Copyright, Terms of Use | Accessibility | NASA OCIO | USA.gov | NASA.govContact Us | Site MapSTI LogoNASA Official: JoAnne R. Calhoun Site Curator: STI Compliance and Distribution Services Last Modified: September 12, 2024