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Showing 1 to 16 of 16 for “"Trailing Edge Noise"”.
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Bio-Inspired Control of Roughness and Trailing Edge Noise
Noise from fluid flow over rough surfaces is an important consideration in the design and performance of certain vehicles with high surface-area-to-perimeter ratios. A new method of noise control based on the anatomy of owls is developed and consists of fabric or fibrous canopies suspended above …
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Prediction of Trailing Edge Noise from Two-Point Velocity Correlations
… developed by Glegg et al. (2004) for solving the trailing edge noise problem. This method is based on the premises that the noise produced by a surface can be computed by the integral of the cross product between the velocity and vorticity fields, of the boundary layer and shed vorticity (Howe …
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Bio-Inspired Trailing Edge Noise Control: Acoustic and Flow Measurements
Trailing edge noise control is an important problem associated mainly with wind turbines. As turbulence in the air flows over a wind turbine blade, it impacts the trailing edge and scatters, producing noise. Traditional methods of noise control involve modifying the physical trailing edge, or the …
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Numerical Study of Synthetic-Jet Actuation Effect on Airfoil Trailing Edge Noise
… Synthetic Jet Actuators (SJAs) as active noise control devices for reduction of airfoil acoustic radiation. High-accuracy numerical efforts employ a sixth-order accurate Navier-Strokes solver implementing a low-pass filtering of poorly resolved high-frequency solution content to retain …
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Effect of Boundary-Layer Tripping on Turbulence Generation and Trailing-Edge Noise in Transitional Airfoils
… focus here on attempting to directly predict the noise associated with airframe by considering a single isolated airfoil. Developing an ability to directly predict the radiated noise and how it is generated is a first step for passive or active control of the generated noise. We choose herein a …
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Understanding the Impact of a Serrated Trailing Edge on the Unsteady Hydrodynamic Field
Trailing edge noise is a common noise source in aerodynamic applications, such as wind turbines, duct fan blades, and propellers. As sound is a nuisance for people near this machinery, methods of reducing trailing edge noise are being investigated. A proven method of trailing edge noise reduction …
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Clean Wing Airframe Noise Modeling for Multidisciplinary Design and Optimization
A new noise metric has been developed that may be used for optimization problems involving aerodynamic noise from a clean wing. The modeling approach uses a classical trailing edge noise theory as the starting point. The final form of the noise metric includes characteristic velocity and length …
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Mathematical Modelling of Acoustic Diffraction Noise Embracing Diverse Boundary Conditions
… tools for modelling acoustic diffraction noise in various contexts and explore improved models for aerofoil-turbulence interaction noise. The thesis is divided into two parts. The first explores variants of half-plane scattering problems and the analytical requirements for their solutions. …
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Boundary Layer Characteristics on a Tiltrotor Blade Model
Boundary layer characteristics at the trailing edge of a tiltrotor blade model were measured using a flattened pitot probe and a single hot wire. The blade was mounted in Virginia Tech Stability Wind tunnel stationary on a turntable on the wind tunnel's upper wall with the tip pointing down. The …
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Numerical Studies of Jet-Wing Distributed Propulsion and a Simplified Noise Metric Method
… research capabilities on reducing emissions and noise produced by aircraft. Modern aircraft use two to four engines arranged on the wing or behind to produce thrust that is concentrated directly behind the engine. Kuchemann suggested a way to improve the propulsive efficiency by changing the …
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Pressure Shielding Mechanisms in Bio-Inspired Unidirectional Canopy Surface Treatments
… mechanism which find application particularly in trailing edge noise reduction.
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Aerodynamic and Acoustic Modeling for eVTOL Rotor Noise Prediction
… 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 …
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Broadband Noise Prediction of an Axial Compressor Operating at Low Reynolds Number
… into the production and prediction of broadband noise in axial compressors operating at low Reynolds number. The low Reynolds number (chord based $Re_C \leq 5\times 10^4$) regime presents new flow physics by the large regions of laminar flow that are present in the compressor. As such it is …
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Aerodynamic broadband noise from contra-rotating open rotors
… their introduction is their very high levels of noise emissions. There is therefore a need for schemes by which the noise from CRORs can be predicted and hence reduced. Nearly all of the research effort on the prediction and reduction of CROR noise has been so far focused on the tonal component, …
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Bio-Inspired Axial Fan Design, 3D Printing Fabrication and Characterization for Noise and Flow Performance Optimization
Noise pollution from mechanical ventilation systems is an increasingly critical issue in the context of global energy transition, post-pandemic air quality requirements, and stringent environmental acoustic regulations. In this context, axial-flow fans represent a key technological component, …
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Numerical investigation of slat noise attenuation using acoustic liners
Noise generated by high-lift devices such as slats on a wing is a major contributor to the overall airframe noise during the landing approach of a commercial aircraft. In this work the concept of attenuating slat noise using absorptive acoustic liners in the slat/main element gap is explored using …