{"id":{"repo_id":"soton","oai_identifier":"oai:eprints.soton.ac.uk:64784"},"canonical_url":"https://search.dev.ndltd.org/etd/soton/oai:eprints.soton.ac.uk:64784","repository":{"repo_id":"soton","name":"University of Southampton","base_url":"https://eprints.soton.ac.uk/cgi/oai2"},"display":{"title":"A statistical jet-noise model based on the acoustic analogy and a RANS solution","abstract":"We introduce a hybrid model for the evaluation of jet noise. The model uses the information from a solution of the Reynolds-averaged Navier-Stokes equations (RANS). It evaluates the jet-noise power spectral density (PSD) in the quiescent region outside the turbulent jet. It includes the following components:1. A propagation model based on the high- and low-frequency approximations of the Lilley analogy Green's function. The high-frequency approximation is determined by combining a moving-medium Lighthill analogy and ray acoustics. The low-frequency model is made by using a flow-factor approach on each component of the source two-point CPSD. Weuse available analytical expressions of flow factors evaluated in the low-frequency limit.2. A fixed-frame source model based on the source terms of the Goldstein (2001) expression for the Lilley analogy. Both the applied-stress and applied-force equivalent acoustic sources are retained. The used acoustic analogy allows for expressing the 2-point covariance of the applied-stress source by using 2-point velocimetry measurements in a turbulent jet. Specifically the applied-stress source can be put in correspondence to the unit-density Reynolds-stress statistics. Available measurements of the unit-density Reynolds-stress 2-point statistics are here used to derive an analytical model for the applied-stress 2-point correlation coefficient. Also the applied-force 2-point statistics, required for modelling noise source mechanisms at the presence of density inhomogeneities in the flow, is expressed on the basis of the unit-density Reynolds-stress 2-point statistics. Numerical methods are used to derive the frequency-wavenumber expression for a volumetric source-strength tensor.3. A jet-flow prediction by using a commercial RANS solver and a set of connection relations expressing source-model parameters starting from the RANS solution. The RANS system includes Reynolds Stress modelling (RSM) closure equations. Turbulence anisotropy is then incorporated in the flow-statistics estimation. The proposed connection relations introduce a set of empirical parameters which are evaluated by matching model components to both velocimetry and acoustics measurements. Modelled far-field jet-noise 1/3-octave spectra are compared to corresponding measurements for isothermal, unheated and hot jets.","abstract_html":"We introduce a hybrid model for the evaluation of jet noise. The model uses the information from a solution of the Reynolds-averaged Navier-Stokes equations (RANS). It evaluates the jet-noise power spectral density (PSD) in the quiescent region outside the turbulent jet. It includes the following components:1. A propagation model based on the high- and low-frequency approximations of the Lilley analogy Green's function. The high-frequency approximation is determined by combining a moving-medium Lighthill analogy and ray acoustics. The low-frequency model is made by using a flow-factor approach on each component of the source two-point CPSD. Weuse available analytical expressions of flow factors evaluated in the low-frequency limit.2. A fixed-frame source model based on the source terms of the Goldstein (2001) expression for the Lilley analogy. Both the applied-stress and applied-force equivalent acoustic sources are retained. The used acoustic analogy allows for expressing the 2-point covariance of the applied-stress source by using 2-point velocimetry measurements in a turbulent jet. Specifically the applied-stress source can be put in correspondence to the unit-density Reynolds-stress statistics. Available measurements of the unit-density Reynolds-stress 2-point statistics are here used to derive an analytical model for the applied-stress 2-point correlation coefficient. Also the applied-force 2-point statistics, required for modelling noise source mechanisms at the presence of density inhomogeneities in the flow, is expressed on the basis of the unit-density Reynolds-stress 2-point statistics. Numerical methods are used to derive the frequency-wavenumber expression for a volumetric source-strength tensor.3. A jet-flow prediction by using a commercial RANS solver and a set of connection relations expressing source-model parameters starting from the RANS solution. The RANS system includes Reynolds Stress modelling (RSM) closure equations. Turbulence anisotropy is then incorporated in the flow-statistics estimation. The proposed connection relations introduce a set of empirical parameters which are evaluated by matching model components to both velocimetry and acoustics measurements. Modelled far-field jet-noise 1/3-octave spectra are compared to corresponding measurements for isothermal, unheated and hot jets.","abstract_has_math":false,"creators":["Bassetti, Alessandro"],"institution":"University of Southampton","degree_name":"Ph.D.","degree_level":"doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Astley, R.J.","Morfey, Christopher L."],"committee_chairs":[],"committee_members":[],"year":2009,"date_issued":"2009-01","date_published":"2009-01","updated_at":"2026-07-24T04:35:54Z","subjects":[],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Astley, R.J.","Morfey, Christopher L."]},{"key":"dc:creator","label":"Author","values":["Bassetti, Alessandro"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2009-01"]},{"key":"dc:date.issued","label":"Date","values":["2009-01"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Fluid Dynamics & Acoustics Group (pre 2011 reorg)","Institute of Sound and Vibration Research"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Southampton"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://eprints.soton.ac.uk/64784/"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Ph.D."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://eprints.soton.ac.uk/64784/1/bassett.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["We introduce a hybrid model for the evaluation of jet noise. The model uses the information from a solution of the Reynolds-averaged Navier-Stokes equations (RANS). It evaluates the jet-noise power spectral density (PSD) in the quiescent region outside the turbulent jet. It includes the following components:1. A propagation model based on the high- and low-frequency approximations of the Lilley analogy Green's function. The high-frequency approximation is determined by combining a moving-medium Lighthill analogy and ray acoustics. The low-frequency model is made by using a flow-factor approach on each component of the source two-point CPSD. Weuse available analytical expressions of flow factors evaluated in the low-frequency limit.2. A fixed-frame source model based on the source terms of the Goldstein (2001) expression for the Lilley analogy. Both the applied-stress and applied-force equivalent acoustic sources are retained. The used acoustic analogy allows for expressing the 2-point covariance of the applied-stress source by using 2-point velocimetry measurements in a turbulent jet. Specifically the applied-stress source can be put in correspondence to the unit-density Reynolds-stress statistics. Available measurements of the unit-density Reynolds-stress 2-point statistics are here used to derive an analytical model for the applied-stress 2-point correlation coefficient. Also the applied-force 2-point statistics, required for modelling noise source mechanisms at the presence of density inhomogeneities in the flow, is expressed on the basis of the unit-density Reynolds-stress 2-point statistics. Numerical methods are used to derive the frequency-wavenumber expression for a volumetric source-strength tensor.3. A jet-flow prediction by using a commercial RANS solver and a set of connection relations expressing source-model parameters starting from the RANS solution. The RANS system includes Reynolds Stress modelling (RSM) closure equations. Turbulence anisotropy is then incorporated in the flow-statistics estimation. The proposed connection relations introduce a set of empirical parameters which are evaluated by matching model components to both velocimetry and acoustics measurements. Modelled far-field jet-noise 1/3-octave spectra are compared to corresponding measurements for isothermal, unheated and hot jets."]},{"key":"dc:format","label":"Dc Format","values":["text"]},{"key":"dc:title","label":"Title","values":["A statistical jet-noise model based on the acoustic analogy and a RANS solution"]}]}],"canonical_facts":{"dc:contributor.advisor":["Astley, R.J.","Morfey, Christopher L."],"dc:creator":["Bassetti, Alessandro"],"dc:date":["2009-01"],"dc:date.issued":["2009-01"],"dc:description.abstract":["We introduce a hybrid model for the evaluation of jet noise. The model uses the information from a solution of the Reynolds-averaged Navier-Stokes equations (RANS). It evaluates the jet-noise power spectral density (PSD) in the quiescent region outside the turbulent jet. It includes the following components:1. A propagation model based on the high- and low-frequency approximations of the Lilley analogy Green's function. The high-frequency approximation is determined by combining a moving-medium Lighthill analogy and ray acoustics. The low-frequency model is made by using a flow-factor approach on each component of the source two-point CPSD. Weuse available analytical expressions of flow factors evaluated in the low-frequency limit.2. A fixed-frame source model based on the source terms of the Goldstein (2001) expression for the Lilley analogy. Both the applied-stress and applied-force equivalent acoustic sources are retained. The used acoustic analogy allows for expressing the 2-point covariance of the applied-stress source by using 2-point velocimetry measurements in a turbulent jet. Specifically the applied-stress source can be put in correspondence to the unit-density Reynolds-stress statistics. Available measurements of the unit-density Reynolds-stress 2-point statistics are here used to derive an analytical model for the applied-stress 2-point correlation coefficient. Also the applied-force 2-point statistics, required for modelling noise source mechanisms at the presence of density inhomogeneities in the flow, is expressed on the basis of the unit-density Reynolds-stress 2-point statistics. Numerical methods are used to derive the frequency-wavenumber expression for a volumetric source-strength tensor.3. A jet-flow prediction by using a commercial RANS solver and a set of connection relations expressing source-model parameters starting from the RANS solution. The RANS system includes Reynolds Stress modelling (RSM) closure equations. Turbulence anisotropy is then incorporated in the flow-statistics estimation. The proposed connection relations introduce a set of empirical parameters which are evaluated by matching model components to both velocimetry and acoustics measurements. Modelled far-field jet-noise 1/3-octave spectra are compared to corresponding measurements for isothermal, unheated and hot jets."],"dc:format":["text"],"dc:identifier.uri":["https://eprints.soton.ac.uk/64784/1/bassett.pdf"],"dc:publisher.department":["Fluid Dynamics & Acoustics Group (pre 2011 reorg)","Institute of Sound and Vibration Research"],"dc:publisher.institution":["University of Southampton"],"dc:relation.isreferencedby":["https://eprints.soton.ac.uk/64784/"],"dc:title":["A statistical jet-noise model based on the acoustic analogy and a RANS solution"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["doctoral"],"dc:type.qualificationname":["Ph.D."]},"updated_at":"2026-07-24T04:35:54Z"}