Turbomachinery Aeroacoustic Calculations using Nonlinear Methods
Doktorsavhandling, 2011

Noise regulations for aircraft that fly over populated areas are becoming continuously stricter. This in combination with increasing computational capabilities has boosted interest in aeroacoustic computations in the aerospace industry. New numerical methods that are able to predict noise will play a major role in future aircraft and engine designs, and validation and possibly improvements of these new methods are needed for results with satisfying accuracy. This thesis shows how nonlinear blade row interaction computations that focus on aeroacoustics can be made in an accurate and efficient way. It is shown how the computations of a succession of blade rows with non-matching blade count can be made more efficient by utilizing the chorochronic periodicity. The tonal acoustic response from a stator vane with rotor wake impingement is calculated with the chorochronic method and compared to a linear method, and the results are in good agreement. The harmonic balance technique was also tested for tone noise predictions and shows a good potential to be a more efficient tool than using standard time stepping for obtaining periodic solutions. The Newton-GMRES method is shown to be a suitable algorithm for obtaining convergence and for better performance of the harmonic balance computations. Broadband noise predictions from rotor wake impingement on stators are calculated with a hybrid RANS/LES method and chorochronic buffer zones. The noise is evaluated with a FWH surface integral method.



Time Spectral


Ffowcs-Williams & Hawkings


Time lag

Computational Aeroacoustics


Rotor-Stator interaction

Buffer layer

Oscillating sphere


Computational Fluid Dynamics

Acoustic analogies


Counter-Rotating Propfan

Harmonic Balance Technique



Chorochronic periodicity


HA2, Hörsalsvägen 4, Chalmers Johanneberg
Opponent: John Coupland, Rolls-Royce plc, UK


Martin Olausson

Chalmers, Tillämpad mekanik, Strömningslära

An Absorbing Inlet Buffer Layer for Rotor Wake/Stator Time Domain Computations

Proceedings of ASME Turbo Expo 2009, June 8-12, 2009, Orlando, Florida, USA,; (2009)p. 709-718

Paper i proceeding

Aeroacoustics and Performance Modeling of a Counter-Rotating Propfan

Proceedings of ASME Turbo Expo 2010, June 14-18, 2010, Glasgow, UK,; (2010)

Paper i proceeding

Evaluation of Nonlinear Rotor Wake/Stator Interaction by using Time Domain Chorochronic Solver

Proceedings of the 8th International Symposium on Experimental and Computational Aerothermodynamics of Internal Flows (ISAIF), Lyon, July 2007,; (2007)

Konferensbidrag (offentliggjort, men ej förlagsutgivet)

Nonlinear Rotor Wake/Stator Interaction Computations

Proceedings of the 18th International Symposium on Air Breathing Engines (ISABE), Beijing, China, 2007,; (2007)

Konferensbidrag (offentliggjort, men ej förlagsutgivet)

Absorbing Inlet Boundary Analysis of Rotor Wake/Stator Time Domain Computations

16th AIAA/CEAS Aeroacoustics Conference, 7-9 June 2010, Stockholm, Sweden,; (2010)

Konferensbidrag (offentliggjort, men ej förlagsutgivet)

Rotor Wake/Stator Broadband Noise Calculations Using Hybrid RANS/LES and Chorochronic Buffer Zones

15th AIAA/CEAS Aeroacoustics Conference, 11-13 May, Miami, Florida,; (2009)

Konferensbidrag (offentliggjort, men ej förlagsutgivet)





Strömningsmekanik och akustik



Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 3162

HA2, Hörsalsvägen 4, Chalmers Johanneberg

Opponent: John Coupland, Rolls-Royce plc, UK