This paper presents the aerodynamic design of low noise wind turbine blades using Betz and Joukowski concepts. The aerodynamic model is based on Blade Element Momentum theory whereas the aeroacoustic prediction model is based on the BPM model. The investigation is started with a 3MW baseline/reference turbine rotor with a diameter of 80 m. To reduce the noise emission from the baseline rotor, t...

The paper presents a design procedure for anti-vortex endplates that are fitted to tip limited blades of the subsonic axial fans utilised in compact cooling units. The authors study the impact of tip leakage vortex bursting on the performance of the studied class of fans. The vortex breakdown occurs in the swirling flows at a blade’s tip, and is found to be a flow feature associated with the pr...

Aerodynamic sound generation at low Mach numbers around complex stationary and moving bodies is computed directly with an immersed-boundary method-based hybrid approach. The complex flow field is solved by the immersed-boundary incompressible Navier-Stokes flow solver and the sound generation and propagation are computed by the linearized perturbed compressible equations with a high-order immer...

A review of recent advances in the use of surface integral methods in Computational AeroAcoustics (CAA) for the extension of near-field CFD results to the acoustic far-field is given. These integral formulations (i.e. Kirchhoff’s method, permeable (porous) surface FfowcsWilliams Hawkings (FW-H) equation) allow the radiating sound to be evaluated based on quantities on an arbitrary control surfa...

On the basis of the traditional structure of noise barrier, this paper seeks aerodynamic load to reduce the variation of maximum surface configuration (porous structure). Using the numerical simulation method, this paper builds a three-dimensional numerical model of deloading type noise barriers and trains. The large fluid calculation software, Fluent, is adopted to conduct simulation calculati...

Owls are widely known for silent flight, achieving remarkably low noise gliding and flapping flights owing to their unique wing morphologies, which are normally characterized by leading-edge serrations, trailing-edge fringes and velvet-like surfaces. How these morphological features affect aerodynamic force production and sound suppression or noise reduction, however, is still not well known. H...

BACKGROUND In this paper, we used the principle of biomimetics to design two-dimensional and three-dimensional bar sections, and used computational fluid dynamics software to numerically simulate and analyse the aerodynamic noise, to reduce drag and noise. METHODS We used the principle of biomimetics to design the cross-section of a bar. An owl wing shape was used for the initial design of th...

Aerodynamic noise becomes significant for high-speed trains and its prediction in an industrial context is hard to achieve. The aerodynamic and aeroacoustic behaviour of the flow past a highspeed train wheelset, one of the main components of a bogie, are investigated at a scale 1:10 using a two-stage hybrid method of computational fluid dynamics and acoustic analogy. The near-field unsteady flo...