In the contest of Urban Air Mobility (UAM), where electric vertical take-off and landing aircraft (eVTOL) are considered the next generation of green and fast transportation in the growing city environment, social acceptability and noise emission are major issues. For this very reason, it is crucial to take in consideration and study the noise generated by this type of vehicles, with the ultimate goal of reducing it. This work aims to investigate the noise generated by the interaction between propellers and wing, typical of such type of aircraft. To do so, in this work a mid-fidelity solver for the flow field is employed and coupled with a classical integral formulation FW-H to compute the far-field acoustic propagation. Through the use of such tools, the noise generated under various operational configurations is analyzed. Initially, a wing with only one propeller mounted near the wing tip is studied, varying the wing-propeller distance. Subsequently, two additional propellers are introduced along the span of the wing to study how the presence of multiple propellers influences the problem and whether different relative propellers positioning affect it. The results show how the relative position of the single propeller with respect to the wing influences the noise generated by the propeller, particularly in some direction. Tho this differences are not excessively intense in the cases analyzed, since wing and propeller always present a relevant distance, the effects found need to be taken carefully in account since a closer positioning of the propeller to the wing could much more affect the noise it generates. Further, the three propellers configuration show how the addition of more propellers over the span of the wing results in a very relevant increase of the noise produced by each propeller in some directions and how this is affected by different propellers streamwise distancing.
Nel contesto della Mobilità Aerea Urbana (UAM), dove i velivoli elettrici a decollo e atterraggio verticali (eVTOL) sono considerati la prossima generazione di forma di trasporto veloce e sostenibile nei crescenti ambienti urbani, l'accettabilità sociale e le emissioni di rumore rappresentano problemi significativi. Per questa ragione, è fondamentale prendere in considerazione e studiare il rumore generato da questo tipo di veicoli, con l'obiettivo finale di ridurlo. Questo lavoro mira a investigare il rumore generato dall'interazione tra eliche e ala, tipica di tali aerei. A tal fine, in questo studio viene utilizzato un solutore di media fedeltà per il campo di flusso, accoppiato con una formulazione integrale classica FW-H per il calcolo della propagazione acustica lontano dalla sorgente. Attraverso l'uso di tali strumenti, viene analizzato il rumore generato sotto varie configurazioni operative. Inizialmente è osservato il comportamento di un modello con un solo motore a elica montato sulla punta dell'ala, analizzando come questo vari cambiando la distanza tra ala e eliche. Successivamente viene studiato come l'introduzione di altri due motori sull'ala modifichi i risultati e che influenza abbia su questi il loro posizionamento relativo. I risultati nel caso con singolo motore, mostrano come il suo posizionamento influisca sul rumore generato solo in alcune direzioni. In particolare, nonostante le differenze percepite nelle configurazioni in analisi non risultino eccessivamente rilevanti per via della presenza di una distanza ala-motore sempre elevata; rimane necessario considerare tale interazione in quanto per casi con i due corpi più ravvicinati il rumore generato potrebbe risultare più intenso. Per quanto riguarda il caso con 3 motori, i risultati mostrano come questi si influenzino vicendevolmente in maniera rilevante, aumentando notevolmente il rumore in alcune direzioni, e come questo sia influenzato da un diverso posizionamento.
Aeroacoustic analysis of the wing-propeller interaction of wingtip-mounted and distributed propulsion configurations for different propeller streamwise positioning
Marindi, Simone
2023/2024
Abstract
In the contest of Urban Air Mobility (UAM), where electric vertical take-off and landing aircraft (eVTOL) are considered the next generation of green and fast transportation in the growing city environment, social acceptability and noise emission are major issues. For this very reason, it is crucial to take in consideration and study the noise generated by this type of vehicles, with the ultimate goal of reducing it. This work aims to investigate the noise generated by the interaction between propellers and wing, typical of such type of aircraft. To do so, in this work a mid-fidelity solver for the flow field is employed and coupled with a classical integral formulation FW-H to compute the far-field acoustic propagation. Through the use of such tools, the noise generated under various operational configurations is analyzed. Initially, a wing with only one propeller mounted near the wing tip is studied, varying the wing-propeller distance. Subsequently, two additional propellers are introduced along the span of the wing to study how the presence of multiple propellers influences the problem and whether different relative propellers positioning affect it. The results show how the relative position of the single propeller with respect to the wing influences the noise generated by the propeller, particularly in some direction. Tho this differences are not excessively intense in the cases analyzed, since wing and propeller always present a relevant distance, the effects found need to be taken carefully in account since a closer positioning of the propeller to the wing could much more affect the noise it generates. Further, the three propellers configuration show how the addition of more propellers over the span of the wing results in a very relevant increase of the noise produced by each propeller in some directions and how this is affected by different propellers streamwise distancing.File | Dimensione | Formato | |
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https://hdl.handle.net/10589/223541