Aerodynamics and Fluid Mechanics Commons^™

Aerodynamic And Acoustic Modeling For Evtol Rotor Noise Prediction, Daniella Bezuidenhout, Anastasios S. Lyrintzis, Vladimir V. Golubev

Doctoral Dissertations and Master's Theses

This thesis presents the development and validation of a methodology for predicting total acoustic emissions from a one-fifth scale electric vertical takeoff and landing (eVTOL) rotor in both hover and edgewise flight conditions. The approach couples sectional two-dimensional Reynolds-Averaged Navier-Stokes (2D-RANS) airfoil simulations with rotor loading predictions from the Comprehensive Hierarchical Aeromechanics Rotorcraft Model (CHARM), tonal noise calculations using the acoustic solver PSU-WOPWOP, and broadband noise predictions from the UCD-QuietFly framework. Boundary-layer inputs traditionally obtained from the viscous-inviscid solver, XFOIL, were replaced with higher-fidelity 2D-RANS results from OpenFOAM to better capture low-Reynolds-number flow physics, including laminar-turbulent transition and laminar separation …

Propeller Noise Prediction Of An Urban Air Mobility Vehicle In Urban Environment, Jie Hua

Doctoral Dissertations and Master's Theses

Urban Air Mobility (UAM) vehicles operate in complex, unsteady aerodynamic environments where wake interactions, gust and turbulence significantly affect both performance and noise generation. Understanding these mechanisms is critical for developing quieter and more efficient eVTOL systems that meet future community noise and certification requirements. This dissertation focuses on the high-fidelity numerical investigation of propeller noise in three representative unsteady loading scenarios: (i) transition (tilt) flight, (ii) edgewise inflow, and (iii) wake–propeller interaction. Each case emphasizes different physical mechanisms that dominate noise generation in UAM operations. Hybrid turbulence-resolving approaches—Detached Eddy Simulation (DES) and Delayed Detached Eddy Simulation (DDES)—are coupled with …

High-Fidelity Modeling Of Evtol Rotor Unsteady Aerodynamic And Aeroacoustic Response To Time-Harmonic Gust, Vadim Voropayev

Doctoral Dissertations and Master's Theses

The rapid emergence of Urban Air Mobility (UAM) demands accurate prediction and mitigation of noise generated by electric vertical take-off and landing (eVTOL) aircraft operating in complex urban environments. Among the various noise sources, the aerodynamic and acoustic response of rotors to unsteady inflow represents a major uncertainty in community-noise assessment and certification. This thesis investigates the aerodynamic and aeroacoustic behavior of a representative eVTOL rotor subjected to time-harmonic inflow disturbances, providing a detailed numerical framework to quantify how periodic gusts influence rotor performance, unsteady loading, and sound radiation.

The study employs a three-stage computational methodology using the open-source solver …

An Engineering Solution For Fan Aeroacoustics Measurements Correction In A Non-Anechoic Testing Environment, Saad-Eldin Taha, Mohamed Y.Zakaria, Mohamed Abdelgaied, M.M. Bassuoni Prof. Dr.

Journal of Engineering Research

Abstract- Nowadays, acoustic signatures of daily used applications are to be minimized. The study of noise generated through aerodynamic interaction with moving bodies has passed through different phases since the early 50s, and this leads to the evolvement of many analytical, empirical and computational techniques in order to be able to estimate the emitted noise. Concerning fan blades, until now the researches are still going for a reliable method for noise estimation during the early phases of design which help in the development of blades with a lower aeroacoustic signature, the Brooks, Pope and Marcolini (BPM) model was chosen to …

The Interaction Of A Transient Forward Axial Disturbance Flow With A Rotor, Zhuorui Li

Doctoral Dissertations and Master's Theses

This research presents an in-depth investigation of the aeroacoustic characteristics of a scaled-down Joby Aviation rotor, focusing on its performance under realistic conditions for urban air mobility (UAM). Utilizing a high-fidelity numerical simulation approach that combines Large-Eddy Simulation (LES) and Unsteady Reynolds-Averaged Navier-Stokes (URANS) models, the study effectively captures the complex aerodynamic and acoustic interactions inherent in rotor operations. Validation of the numerical framework was achieved through comprehensive comparisons with available experimental data, demonstrating a high level of accuracy in predicting both aerodynamic performance metrics, including thrust and torque, as well as acoustic emissions. The simulation revealed significant impacts resulting …

Aeroacoustics Applications To Jets And Rotors, Michael Marques G.

Doctoral Dissertations and Master's Theses

Aeroacoustics plays a critical role in the advancement of propulsion technologies for both conventional and emerging aerial systems. This dissertation investigates two key topics: noise suppression in supersonic rectangular jets and rotor noise characterization in hover and ground effect. Using high-fidelity numerical simulations and theoretical analyses, this research aims to develop effective noise mitigation strategies and improve predictive methodologies.

The first part of this study focuses on the reduction of noise in supersonic rectangular jets through active control techniques. A novel approach utilizing unsteady microjet actuation at the nozzle lip is explored to disrupt the formation of large-scale turbulent structures …

Bi-Modal Excitation Of A Supersonic Rectangular Jet, Benjamin Malczewski

Doctoral Dissertations and Master's Theses

This work addresses the issue of supersonic rectangular jet noise via bi-modal excitation. A Mach 1.5 heated rectangular jet with a 2:1 aspect ratio is considered. Theoretical work is presented in which a Reduced-Order Model (ROM) is used in conjunction with the Linearized Euler Equations to predict the nonlinear growth and decay of various frequencies due to the interaction between harmonically related modes and the mean flow. Scope is limited to a symmetric disturbance. The case of no interaction is used to help identify a dominant coherent structure, referred to as “f”. For the symmetric disturbance, a Strouhal number of …

Dynamics Of A 3-D Inlet/Isolator Measured With Fast Pressure-Sensitive Paint, Andrew N. Bustard, Mark E. Noftz, Mitsugu Hasegawa, Hirotaka Sakaue, Joseph S. Jewell, Nicholas J. Bisek, Thomas J. Juliano

Publications

Fast pressure-sensitive paint (PSP) was applied to an inlet/isolator designed using the Osculating Internal Waverider Inlet with Parallel Streamlines (OIWPS) method. The dorsal isolator surface pressure was measured using anodized-aluminum PSP through transparent cast acrylic that makes up the ventral portion of the isolator. Temperature-sensitive paint was utilized to correct for the PSP’s temperature sensitivity. The model was tested under Mach 5.7 flow at Re = 8.5 ×106 /m and 10.2 ×106 /m in the AFOSR–Notre Dame Large Mach-6 Quiet Tunnel (ANDLM6QT) under conventional noise conditions. Flow phenomena, such as shocks originating in the inlet and flow separation at the …

The Numerical Study Of Aeroacoustics Performance Of Wings With Different Wavelength Leading-Edge Tubercles, Youjie Zhang

Honors Undergraduate Theses

The leading-edge tubercle is a type of airfoil modification that inspired by the humpback whale. It was found that the aerodynamic performance of the wing would increase compared to the wing without tubercles. In the past several years, a lot of numerical and experimental studies have been accomplished to explore this leading-edge modification. Besides the aerodynamic performance change, this research explores the aeroacoustics behavior of airfoils with leading-edge tubercles. A numerical study based on Computational Fluid Dynamics (CFD) is established, and simulations using Star CCM are accomplished based on reasonable set-ups. The airfoil chosen to create the wing is NACA …

Mitigation Of Aeroacoustic Noise Of A Fixed Wing Using Passive Flow Control, Cameron L. Perry

College of Graduate Studies: Theses & Dissertations

As the world becomes more environmentally conscious, noise pollution is of increasing concern. In this study, shallow dimples are applied to a NACA 0012 airfoil at multiple angles of attack (AoA) with the intent of reducing aeroacoustic noise emissions. Both Reynolds Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) models are used for aerodynamic and aeroacoustic investigations, respectively, at a fixed Reynolds number of 4.8 x 10⁵. Altering the dimple depth to diameter ratio (d/D) from 2.5% to 15% is first investigated, with a d/D of 5% or lower resulting in the least aerodynamic impact. The transition from …

Jet Noise Reduction: A Fresh Start, Christopher K. Tam, Fang Q. Hu

Mathematics & Statistics Faculty Publications

Attempts to reduce jet noise began some 70 years ago. In the literature, there have been many publications written on this topic. By now, it is common knowledge that jet noise consists of a number of components. They possess different spectral and radiation characteristics and are generated by different mechanisms. It appears then that one may aim at the suppression of the noise of a single component instead of trying to reduce jet noise overall. The objective of the present project is to reduce large turbulence structures noise. It is the most dominant noise component radiating in the downstream direction. …

On The Implementation And Further Validation Of A Time Domain Boundary Element Method Broadband Impedance Boundary Condition, Fang Q. Hu, Douglas M. Nark

Mathematics & Statistics Faculty Publications

A time domain boundary integral equation with Burton-Miller reformulation is presented for acoustic scattering by surfaces with liners in a uniform mean flow. The Ingard-Myers impedance boundary condition is implemented using a broadband multipole impedance model and converted into time domain differential equations to augment the boundary integral equation. The coupled integral-differential equations are solved numerically by a March-On-in-Time (MOT) scheme. While the Ingard-Myers condition is known to support Kelvin-Helmholtz instability due to its use of a vortex sheet interface between the flow and the liner surface, it is found that by neglecting a second derivative term in the current …

Aeroacoustics Of Supersonic Jet Interacting With Solid Surfaces And Its Suppression, Seyyed Saman Salehian

Doctoral Dissertations and Master's Theses

The noise generated by supersonic jet is of primary interest in the high-speed flight. In several flight conditions jet exhaust of the propulsion system interacts with solid surfaces. For example, jet impingement on ground for a rocket lift-off, or interactions influenced by the integration of the engine with the airframe. Such complex applications require consideration of the role of acoustic-surface interactions on the noise generation of the jet and its radiation. Numerical analysis of supersonic jet noise involved in these scenarios is investigated by employing Hybrid Large Eddy Simulation – Unsteady Reynolds Averaged Simulation approach to model turbulence.

First, the …

Rotor-On-Rotor Aeroacoustic Interactions Of Multirotor In Hover, Eduardo Alvarez, Austin Schenk, Tyler Critchfield, Andrew Ning

Faculty Publications

Multirotor configurations introduce complicated aerodynamic and aeroacoustic interactions that must be considered during aircraft design. In this paper we explore two numerical methods to model the acoustic noise caused by aerodynamic rotor-on-rotor interactions of rotors in hover. The first method uses a conventional mesh-based unsteady Reynolds-average Navier-Stokes (URANS) solver, while the second consists of a meshless Lagrangian solver based on the viscous vortex particle method (VPM). Both methods are coupled with an aeroacoustics solver for tonal and broadband noise predictions. Noise predictions are validated for single and multi-rotor configurations, obtaining with the VPM a similar accuracy than URANS while being …

2d Aeroacoustic Analysis Of Flow In The Flame Trench, Meghan Pokorski

Doctoral Dissertations and Master's Theses

We present here a methodology for using the commercial software ANSYSFLUENT to predict the acoustic field associated with Space-Launch System (SLS). We consider a two-dimensional model of flame deflector, and flame trench. The ANSYS code is then used to simulate the internal flow. Both the steady state case is considered along with other cases where the inflow has a harmonic component. A Ffowcs-Williams Hawking (FWH) surface is then constructed within the computational domain to use the computed flow fluctuations to obtain the acoustic field. The acoustic data was then compared to the experimental data.

When using the ANSYS code for …