Measurements of near-wall pressure fluctuations for trailing-edge serrations and slits

Abstract: Pressure fluctuations on the suction side of a NACA 0018 with trailing-edge add-ons are obtained from integration of time-resolved stereoscopic and tomographic particle image velocimetry data and compared to the ones computed from Lattice–Boltzmann simulations. The airfoil is retrofitted with solid and slitted serrated trailing...

Noise reduction mechanisms of sawtooth and combed-sawtooth trailing-edge serrations

Trailing-edge serrations are add ons retrofitted to wind-turbine blades to mitigate turbulent boundary-layer trailing-edge noise. This manuscript studies the physical mechanisms behind the noise reduction by investigating the far-field noise and the hydrodynamic flow field. A conventional sawtooth and a combed-sawtooth trailing-edge serration...

Computational aeroacoustic approaches for wind turbine blade noise prediction

Acoustic measurements of a DU96-W-180 airfoil with flow-misaligned serrations at a high Reynolds number in a closed-section wind tunnel

Trailing-edge serrations are passive noise reduction add-ons widely used in wind-turbine applications. This study presents acoustic beamforming results of microphone array measurements of a cambered airfoil (DU96-W-180) in a closed-section wind-tunnel at a Reynolds number of industrial interest. Two different serration geometries with different...

Numerical study on combed teeth serrations for wind turbine noise reduction

This study investigates the flow topology and noise emission from a wind turbine airfoil with combed serration trailing edge geometry, to understand the noise reduction observed in earlier experiments. A comparison is made to a straight trailing edge and a serrated trailing edge without combs. The different trailing edges are retrofitted to a...

Numerical analysis of noise reduction mechanisms of serrated trailing edges under zero lift condition

The relation between the far-field noise and the flow field, in presence of serrated and combed-serrated trailing edge, is studied to explain the associated noise reduction mechanisms. Both serration geometries are retrofitted to a NACA 0018 wing. Computations are carried out by solving the fully explicit, transient, compressible Lattice...

Benefits of curved serrations on broadband trailing-edge noise reduction

Far-field noise and flow field over a novel curved trailing-edge serration (named as iron-shaped serration) are investigated. Spectra of the far-field broadband noise, directivity plots and the flow-field over the iron-shaped serration are obtained from numerical computations performed using a compressible Lattice-Boltzmann solver. The new...

Near-wall pressure fluctuations over noise reduction add-ons

Concave serrations on broadband trailing edge noise reduction

The far-field noise and flow field of a novel curved trailing-edge serration (i.e. iron-shaped) are investigated. Spectra of the far-field broadband noise, directivity plots and the flow-field over the iron-shaped serration are obtained from numerical computations performed using a compressible Lattice-Boltzmann solver. The new design is...

On the aeroacoustic properties of a beveled plate

The flow around a beveled flat plate model with an asymmetric 25 degrees trailing edge with three rounding radii is analyzed using a Navier-Stokes based open source software package OpenFOAM in order to predict the aeroacoustic properties of the models. A Large Eddy Simulation with a dynamic Smagorinsky and implicit model are used as closure...

On the Estimation of Spanwise Pressure Coherence of a Turbulent Boundary Layer over a Flat Plate

A Large Eddy Simulation (LES) with four different closure models are analyzed in OpenFOAM, an open source Computional Fluid Dynamics (CFD) package and validated for the determination of the streamwise and spanwise coherence length of the pressure field below a turbulent boundary layer at low Reynolds numbers. Matching results are found for outer...