Laboratory for Mechanisms of Noise Generation and Modal Analysis

• The Laboratory has developed and tested a method for azimuthal decomposition of noise of reactive jet near a deflecting surface. For the first time in the world we have completed measurements of azimuthal modes of an aircraft engine using a full-scale test rig.

• We have developed a method for measuring the modal composition of noise in the air intake channel of an aircraft engine. For the fist time in Russian practice we have gathered experimental data on azimuthal composition of noise in an air intake channel and performed localization of noise sources in a modern aircraft engine.

• The Laboratory has developed method for experimental research of acoustic and aerodynamic and flight characteristics of moving multipole sources of various sizes. The research has been conducted using multi-channel measurements. We have developed and tested a method for beamforming for localization of noise sources of the dipole type.

• We have developed and tested a method for measuring azimuthal and radial structure of noise field in the presence of impedance reflection on the walls. A method has been developed for choosing placement schemes for cells of sound-absorbing surfaces with increased sound-absorbing abilities in a wide range of frequencies, as well as a method for determining acoustic characteristics of large-scale sound-absorbing structures under a selected set azimuthal modal composition of the noise field.

Implemented results of research:

• We have created computer software for determining the optimal location of microphones in flat and ring multi-microphone grids. We have processed measurements of acoustic data that allowed us to determine the modal structure of noise in an aircraft engine. Two registration certificates for computer software. These programs have been used for tuning the experiment program and processing results of acoustic measurements of an aircraft engine on an open test bed.

• Computer software has been created to design efficient sound-absorbing structures for channels of aircraft engines. Using this software we have developed sound-absorbing structures with resonance cells that have new configurations. Such structures have better sound-absorption capabilities in a wide range of frequencies. 3 patents and 4 registration certificates for computer software have been obtained.

• A technology has been developed for producing sound-absorbing structures with enhanced sound-absorption capabilities that can be installed onto prospective Russian aircraft engine, 1 patent has been obtained.

• An input device for a 40-channel spinning mode generator has been developed, 1 patent has been obtained.

• An interferometer with control of the pressing force of the acoustic liner sample has been developed, which makes it possible to reduce the spread of the obtained acoustic characteristics, 1 patent has been obtained.

Education and career development:

• 7 disciplines have been developed and launched into the learning process of the Perm National Research Polytechnic University for maters students: «Aircraft engines»: «Mathematical basics of acoustics», «Basics of acoustics research», «Modern methods of acoustic measurements», «Theory and practice of acoustic signals and fields processing», «The finite element method for problems of acoustics», «Quantitative modeling of acoustic processes in aircraft engines».

• Two additional training programs have been created for professionals of other organizations. 21 professional has completed the programs.

• 14 members of the academic staff of the Laboratory have been admitted to postgraduate schools.

• 1 doctoral dissertation, 4 candidate dissertations, 5 specialists dissertations, 4 masters dissertations, 5 bachelors dissertations have been defended.

Organizational and structural changes:

A unique scientific facility «Acoustic anechoic chamber with aerodynamic noise sources» that has been actively used for research within grant-sponsored and commercial projects.

Collaborations:

• Central Aerohydrodynamic Institute (Russia), OJSC Aviadvigatel» (Russia): joint research, publication, internships of students, postgraduates and young scientists
• Bruel&Kjaer (Denmark): joint research, creation of an optimized antenna for identifying modal structure of noise in cylindrical channels