Wall-treatments for closed-section wind-tunnel aeroacoustic tests
H.F. (Hugo) Mourão Bento
Doctoral Candidate
Dr. D. (Daniele) Ragni
Assistant Professor
The goal of the project is to design innovative solutions to increase the signal to noise ratio for acoustic measurements with microphone arrays in conventional closed test section wind tunnel (e.g. the LTT, in TU Delft) using both experiments and computations. Whereas open test section wind tunnels have the advantage of providing more accurate noise measurements, which can be further improved by using anechoic open-jet tunnels (e.g. the A-tunnel, in TU Delft), closed test section wind tunnels have the advantage of providing more accurate aerodynamic flowfield realizations.
There are several challenges associated with acoustic measurements in closed test section wind tunnels: wall reflections, acoustic noise from the boundary layer of the tunnel walls, hydrodynamic pressure fluctuations occurring in the boundary layer of the wall where the microphones are placed, and acoustic noise from the wind tunnel fan.
Within the THAMES project, the goal of the research is to improve the wind tunnel test section. Possible solutions include surface lining (with a sound absorbing material), substituting the test section walls by Kevlar walls (material transparent to sound), and using a 3D beamforming array. A relevant application of the study is to improve the acoustic measurements of wind turbine blades.
Bento, H. F., Ragni, D., Avallone, F., Simons, D., & Snellen, M. (2022). Acoustic wall treatments for wind tunnel aeroacoustic measurements. Applied Acoustics, 199, 108989.
Mourão Bento, H.F., VanDercreek, C.P., Avallone, F., Ragni, D. and Snellen, M., 2022. Lattice Boltzmann very large eddy simulations of a turbulent flow over covered and uncovered cavities. Physics of Fluids, 34(10), p.105120.
Hugo Bento was born in Lisbon, Portugal, where he completed his BSc degree in Aerospace engineering at Instituto Superior Técnico. He pursued his MSc in Aerospace Engineering at Delft University of Technology. His numerical thesis research focused on ducted propeller aerodynamic performance. He is currently doing experimental and numerical research at TU Delft as a PhD candidate. The research focuses on the application of wall liners to closed wind tunnel test sections, with applications to wind turbine blade acoustic measurements.
Daniele Ragni graduated in Thermo-Mechanical Engineering at the Polytechnic University of Marche (2007). Obtained the Ph.D. in 2012 (Faculty of Aerospace Engineering TU Delft) and joined TU Delft at the section of Wind Energy in the AWEP Department in the same year.
