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...

Free-Stream Effects on Jet-Installation Noise of a Dual-Stream Engine

An investigation of the effects of free-stream on jet-installation noise is performed using a numerical solver based on the lattice-Boltzmann method. In order to simulate a realistic configuration, a high-lift wing comprised by a main element and a deployed flap (MD30P30N) is placed in the vicinity of a dual-stream engine (GE90-94B). The engine...

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...

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 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...