Representing full-scale wind turbine noise

A computer system comprises:

• one or more processor devices;
• memory coupled to the one or more processor devices;
• storage storing executable computer instructions for conducting an air flow simulation, the instructions to configure the one or more processors to:
• import a file containing a digitized representation of a three-dimensional blade geometry;
• extract from the file, blade constructive parameters including at least an airfoil profile, a sectional chord and a twist, and a coordinate shift/rotation matrix from an original 3D to a canonical 2D reference system;
• calculate an air flow past a wind-turbine that includes the three-dimensional blade geometry, based on a Blade Element Momentum Theory (BEMT) that is coupled with a viscous calculation of an airfoil polar to determine a sectional angle of attack and a free-stream velocity, a boundary layer transition, and acoustic noise results;
• perform an air flow simulation for a given number of blade sections of the digitized representation of the three-dimensional blade geometry using a scale-resolving computational fluid dynamics flow simulation;
• compute noise spectra at virtual microphone rings for each blade section;
• import noise spectra generated by every blade section for each virtual microphone of the virtual microphone rings;
• blend the noise spectra generated by each blade section into a smooth variation over one rotor revolution;
• generate synthetic noise signals from each noise spectra by applying an inverse Fourier transform of the noise spectra along a rotor revolution and random phase variation;
• and
• convert the noise spectra into audio tracks.

A computer program product tangibly stored on a computer readable non-transitory storage device that stores executable computer instructions for conducting an air flow simulation, the instructions for causing a computing system to:

• import a file containing a digitized representation of a three-dimensional blade geometry;
• extract from the file, blade constructive parameters including at least an airfoil profile, a sectional chord and a twist, and a coordinate shift/rotation matrix from an original 3D to a canonical 2D reference system;
• calculate an air flow past a wind-turbine that includes the three-dimensional blade geometry, based on a Blade Element Momentum Theory (BEMT) that is coupled with a viscous calculation of an airfoil polar to determine a sectional angle of attack and a free-stream velocity, a boundary layer transition, and acoustic noise results;
• perform an air flow simulation for a given number of blade sections of the digitized representation of the three-dimensional blade geometry using a scale-resolving computational fluid dynamics flow simulation;
• compute noise spectra at virtual microphone rings for each blade section;
• import noise spectra generated by every blade section for each virtual microphone of the virtual microphone rings;
• blend the noise spectra generated by each blade section into a smooth variation over one rotor revolution;
• generate synthetic noise signals from each noise spectra by applying an inverse Fourier transform of the noise spectra along a rotor revolution and random phase variation;
• and
• convert the noise spectra into audio tracks.