Aerodynamic sound generated from cylindrical objects, auch as in pantographs of trains, is a prime noise source in high speed vehicles. The objective is to understand the generation mechanism of the aerodynamic sound from two-dimensional cylinders in order to contribute to the prediction and control of high speed vehicle noise. Aerodynamic sound generated from a square cylinder with various angles of attack is measured in relation to the surface pressure fluctuations on the cylinder. Coherent length and the phase characteristics of the surface pressure fluctuations are measured and the aerodynamic sound level is predicted based on the theory of Lighthill-Curle. Flow around a square cylinder changes drastically at the angle of attack at around 13 deg of angle, when the separated flow from the leading edge re-attaches on a side surface, and shows the lowest sound level. Predicted sound pressure level agrees well with the measured value for the most range of angles od attack.
Experimental investigations and prediction of aerodynamic sound generated from square cylinders
Experimentelle Untersuchungen und Vorhersage des von quadratischen Zylindern erzeugten aerodynamischen Schalls
1998
6 Seiten, 14 Bilder, 5 Quellen
Conference paper
English
Schnellbahn , Fahrzeugaerodynamik , Geräuschemission , Pantograph , Schallquelle , Aerodynamik , Zylinder (Körper) , Quadrat , zweidimensionale Darstellung , Vorhersage , Anstellwinkel (Tragflügel) , Schalldruck , Fluktuation (Physik) , Rechenmodell , Wirbelströmung , Vergleichsmessung , Strömungstrennung , Verifikation
Aerodynamic sound from a square cylinder with a downstream wedge
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