Technical Notes: Comment on the "Minimum Weight Design of Helicopter Rotor Blades with Frequency Constraints," Journal of the American Helicopter Society, October, 1989

It appears that most of the weight saving from the reference blade to the minimum-weight blade is in the region of the blade root. Undoubtedly, the reference blade requires this weight increase to accommodate the usual bending fatigue lo...

KB Amer - 《Journal of the American Helicopter Society》

Thermoacoustic Sources and Instabilities

Thermoacoustics deals with the acoustics of flows in which the variation of entropy plays a significant role. A range of processes are thermoacoustic sources. For example, unsteady combustion, diffusion of heat and mass and turbulent tw...

DG Crighton，AP Dowling，JEF Williams，... - Springer London

A new boundary integral formulation for the prediction of sound radiation

A new boundary integral formulation is presented for the evaluation of the noise radiated in a uniform medium by generic sources. To use the method one req...

PD Francescantonio - 《Journal of Sound & Vibration》

Introduction to Generalized Functions with Applications in Aerodynamics and Aeroacoustics

Generalized functions have many applications in science and engineering. One useful aspect is that discontinuous functions can be handled as easily as cont...

F Farassat - NASA Langley Technical Report Server

The Uses and Abuses of the Acoustic Analogy in Helicopter Rotor Noise Prediction

The generation of noise by helicopter rotor blades is considered theoretically, reviewing recent analyses based on the acoustic analogy (where the effect o...

F Farassat，KS Brentner - Aerodynamics and Aeroacoustics

An introduction to generalized functions with some applications in aerodynamics and aeroacoustics

In this paper, we start with the definition of generalized functions as continuous linear functionals on the space of infinitely differentiable functions w...

F Farassat

Rotating Kirchhoff method for three-dimensional transonic blade-vortex interaction hover noise

Three-dimensional transonic blade-vortex interaction (BVI) noise is studied numerically. The unsteady transonic full-potential rotor (FPR) code is used for the simulation of the transonic BVI near-field flow. The rotating Kirchhoff metho...

Y Xue，AS Lyrintzis - 《Aiaa Journal》

Model rotor high-speed impulsive noise - Parametric variations and full-scale comparisons

The results of a 1/7-scale model of the AH-1 series helicopter main rotor test in the German-Dutch anechoic wind tunnel are discussed, with emphasis given on exploring the important scaling parameters of helicopter-rotor high-speed impul...

WR Splettstoesser，KJ Schultz，FH Schmitz，...

The Uses and Abuses of the Acoustic Analogy in Helicopter Rotor Noise Prediction

This paper is theoretical in nature and addresses applications of the acoustic analogy in helicopter rotor noise prediction. It is argued that in many inst...

Farassat，F.，Brentner，... - 《Journal of the American Helicopter Society》

AIAA-87-2675 Quadrupole Source in Prediction of the Noise of Rotating Blades A New Source Description

This paper is theoretical in nature and addresses applications of the acoustic analogy in helicopter rotor noise prediction. It is argued that in many inst...

F Farassat