@article {Lilly:2020:0736-2935:935,
title = "Noise Generated by Stiffening Rods in a Flat Oval HVAC Duct",
journal = "INTER-NOISE and NOISE-CON Congress and Conference Proceedings",
parent_itemid = "infobike://ince/incecp",
publishercode ="ince",
year = "2020",
volume = "262",
number = "1",
publication date ="2020-10-12T00:00:00",
pages = "935-941",
itemtype = "ARTICLE",
issn = "0736-2935",
url = "https://ince.publisher.ingentaconnect.com/content/ince/incecp/2020/00000262/00000001/art00109",
author = "Lilly, Jerry",
abstract = "The sound power level generated by airflow across 1/4" diameter vertical stiffening rods placed inside a 47" x 12" flat oval duct were measured in a reverberation chamber at airflow velocities ranging from 2,000 fpm to 4,500 fpm. The purpose of the stiffening rods was
to prevent the duct walls from sagging and to reduce the low frequency breakout noise. The test results revealed that the regenerated noise was dominated by narrow band noise near the aeolian tone frequency with a sound power level that is proportional to the 6th power of the airflow velocity
and the total length of rods exposed in the airstream.",
}