{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/70568"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/70568","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Effect of liner thickness on acoustic wave propagation in ducts","abstract":"The acoustic characteristics of a point-reacting duct liner that consists of a porous facing sheet backed by cellular cavities are derived by examining the wave propagation within the liner. The relation between the derived expression for the liner acoustic admittance and a semi-empirical formula that is widely used in the literature is discussed. The influence of the liner on acoustic propagation in a duct is examined for the case of a plane duct that carries a uniform mean flow. Numerical results for the attenuation rates vs. frequency are presented. These results. are of three types: (1) comparisons with previously published results for no backing cavity and no mean flow are made, and these results are extended to include the effects of the mean flow; (2) results of parametric variations of the liner dimensions are presented to assess the relative influence of the facing-sheet thickness and the cavity depth; (3) results from the derived expression for liner specific admittance and from the semi-empirical formula are compared in order to determine the significance of the wave propagation within the porous material and to determine the range of validity of the semi-empirical formula.","abstract_html":"The acoustic characteristics of a point-reacting duct liner that consists of a porous facing sheet backed by cellular cavities are derived by examining the wave propagation within the liner. The relation between the derived expression for the liner acoustic admittance and a semi-empirical formula that is widely used in the literature is discussed. The influence of the liner on acoustic propagation in a duct is examined for the case of a plane duct that carries a uniform mean flow. Numerical results for the attenuation rates vs. frequency are presented. These results. are of three types: (1) comparisons with previously published results for no backing cavity and no mean flow are made, and these results are extended to include the effects of the mean flow; (2) results of parametric variations of the liner dimensions are presented to assess the relative influence of the facing-sheet thickness and the cavity depth; (3) results from the derived expression for liner specific admittance and from the semi-empirical formula are compared in order to determine the significance of the wave propagation within the porous material and to determine the range of validity of the semi-empirical formula.","abstract_has_math":false,"creators":["Shaker, B. 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The relation between the derived expression for the liner acoustic admittance and a semi-empirical formula that is widely used in the literature is discussed. The influence of the liner on acoustic propagation in a duct is examined for the case of a plane duct that carries a uniform mean flow. Numerical results for the attenuation rates vs. frequency are presented. These results. are of three types: (1) comparisons with previously published results for no backing cavity and no mean flow are made, and these results are extended to include the effects of the mean flow; (2) results of parametric variations of the liner dimensions are presented to assess the relative influence of the facing-sheet thickness and the cavity depth; (3) results from the derived expression for liner specific admittance and from the semi-empirical formula are compared in order to determine the significance of the wave propagation within the porous material and to determine the range of validity of the semi-empirical formula."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Effect of liner thickness on acoustic wave propagation in ducts"]}]}],"canonical_facts":{"dc:contributor.department":["Engineering Science and Mechanics"],"dc:creator":["Shaker, B. S."],"dc:date.accessioned":["2016-04-21T15:35:25Z"],"dc:date.available":["2016-04-21T15:35:25Z"],"dc:date.issued":["1974"],"dc:description.abstract":["The acoustic characteristics of a point-reacting duct liner that consists of a porous facing sheet backed by cellular cavities are derived by examining the wave propagation within the liner. The relation between the derived expression for the liner acoustic admittance and a semi-empirical formula that is widely used in the literature is discussed. The influence of the liner on acoustic propagation in a duct is examined for the case of a plane duct that carries a uniform mean flow. Numerical results for the attenuation rates vs. frequency are presented. These results. are of three types: (1) comparisons with previously published results for no backing cavity and no mean flow are made, and these results are extended to include the effects of the mean flow; (2) results of parametric variations of the liner dimensions are presented to assess the relative influence of the facing-sheet thickness and the cavity depth; (3) results from the derived expression for liner specific admittance and from the semi-empirical formula are compared in order to determine the significance of the wave propagation within the porous material and to determine the range of validity of the semi-empirical formula."],"dc:description.degree":["Master of Science"],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/10919/70568"],"dc:language.iso":["en"],"dc:publisher":["Virginia Polytechnic Institute and State University"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["Effect of liner thickness on acoustic wave propagation in ducts"],"dc:type":["Thesis"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Engineering Science and Mechanics"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:35Z"}