Blade Noise Reduction

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Moshman Research is developing a new technique for aero-acoustic noise suppression that we believe can have a dramatic reduction on a helicopter’s main rotor blade noise. This could reduce noise in cities and open up precious airspace as well as reduce the warning time for military rotorcraft. We are seeking partners and investors in this technology. The video below was made using our HAM tool.

Simulations of the noise in the plane of a helicopter blade tip rotating at Mach .85 with advance ratio .05 over three revolutions with (Right) and without (Left) our novel noise suppression technique.
Pressure field from transonic flow around a NACA0012 airfoil. The high pressure region around the trailing tip creates a wake that accounts for most of the far-field noise.
The same transonic flow from above using our novel noise suppression technology. The pressure on the trailing tip has been reduced to ambient levels, greatly reducing the far-field noise.
Comparison of the noise levels over time as heard by far-field observers with (Right) and without (Left) our novel noise suppression technology.
Qualitative comparison of the noise power frequency spectrum as heard by the same far-field observers with (Right) and without (Left) our novel noise suppression technology. The lowest frequency noise is at the blade pass frequency and the power in the second and third harmonic are also shown.