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Di Luca Matteo

Adjoint scientifique HES

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Adjoint scientifique HES

Desktop: D2S4

Haute école du paysage, d'ingénierie et d'architecture de Genève
Rue de la Prairie 4, 1202 Genève, CH

Faculty
Technique et IT

Main Degree Programme
Génie mécanique

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Ongoing

BRIDGE SAFE: Measurement and Replication of Drone-Scale Atmospheric Turbulence in a Simulator of Autonomous Flight Environments for Drone Certification.

Role: Collaborator

Financement: Swiss National Science Foundation

Description du projet :

Measurement and Replication of Drone-Scale Atmospheric Turbulence in a Simulator of Autonomous Flight Environments (SAFE) for Drone Certification.

Research team within HES-SO: Di Luca Matteo , Noca Flavio

Partenaires académiques: Koumoutsakos Petros, ETHZ, Zurich; Scartezzini Jean-Louis, EPFL, Lausanne; Giometto Marco, Columbia University, New York

Durée du projet: 01.03.2021 - 28.02.2023

Montant global du projet: 1'000'000 CHF

Url of the project site: https://p3.snf.ch/project-187149

Statut: Ongoing

Completed

The Use of Separation Induced Laminar To Turbulent Flow Transition to Improve the Performance and Robustness of Low Reynolds Numbers Airfoils and Wings

Role: Co-applicant

Requérant(e)s: Breuer Kenneth, Brown University, Providence, USA

Financement: Brown University

Description du projet :

The PhD thesis project aimed at improving aerodynamic performance (i.e. lift, efficiency and power factor), of airfoils and wings operating in the low Reynolds numbers regime, and robustness of performance against freestream turbulence. Key achievements: +30% to +100% aerodynamic efficiency and power factor improvement for airfoils at Re < 30,000 by forcing flow separation to promote laminar to turbulent transition. Methods: theoretical study of spatial flow instability with a 4th order differential equation eigenvalue problem (Orr-Sommerfeld), CFD and wind tunnel experiments (force and hot wire measurements, PIV).

Research team within HES-SO: Di Luca Matteo

Partenaires académiques: Breuer Kenneth, Brown University, Providence, USA

Durée du projet: 01.09.2016 - 15.01.2021

Montant global du projet: 500'000 CHF

Statut: Completed

2021

The Use of Separation Induced Laminar to Turbulent Flow Transition to Improve the Performance and Robustness of Low Reynolds Numbers Airfoils and Wings

Doctoral thesis

Di Luca Matteo

2021, Providence, Rhode Island, United States of America : Brown University. 148 p.

Breuer Kenneth

Link to the publication

Summary:

This thesis dissertation aims at improving aerodynamic performance (i.e. lift, efficiency and power factor), of airfoils and wings operating in the low Reynolds numbers regime, and robustness of performance against freestream turbulence. Below is a brief introduction of the contents. The Introduction gives an overview of the problems tackled in the thesis. Chapter 2 “A bioinspired Separated Flow wing provides turbulence resilience and aerodynamic efficiency for miniature drones” is a journal article published in Science Robotics. Miniature drone power consumption and subsystem efficiency scaling laws and more characterization of the Separated flow Airfoil and Wing are provided in Appendix A, which were included in the published paper as Supplementary Materials. Chapter 3 “Wall distance effects on transition to turbulence in low-Re numbers separated flows” by Matteo Di Luca and Kenneth Breuer is a journal article published in AIAA Journal. Supplemental materials about the linear stability algorithms, data post-processing and noise filtering are provided in Appendix B. Chapter 4 “Cavities improve the power factor of low Reynolds number airfoils and wings” by Matteo Di Luca, Stefano Mintchev and Kenneth Breuer is an article currently under review for journal publication.

Cavities improve the power factor of low Reynolds numbers airfoils and wings

Scientific paper

Di Luca Matteo, Kenneth Breuer, Stefano Mintchev

AIAA Journal (American Institute of Aeronautics and Astronautics Journal), 2021 , vol. In press

Summary:

The poor aerodynamic power factor of low Reynolds numbers airfoils greatly limits the flight time of small-scale drones. Although the power factor can be improved by maintaining a turbulent boundary layer over the wing, this is challenging to achieve at Reynolds numbers below 50,000. We present a design strategy combining high airfoil camber and a cavity carved into the suction side of the airfoil to generate a turbulent, attached flow. The camber of a low Reynolds number AG14 airfoil is increased from 2% to 7% while the cavity position, length and depth are derived based on spatial linear stability theory of the separated shear layer over the cavity. Lift and power factors of the modified airfoils are characterized computationally using XFOIL. The higher camber cavity airfoils show a 100% gain in power factor over a smooth AG14 at Reynolds 30,000 and 10,000. Wind tunnel testing of wings with the cavity airfoils showed power factor improvements of 30% and 80% at Reynolds 30,000 and 10,000 and hot wire measurements confirmed that the cavity triggers a turbulent boundary layer. Finally, it is suggested that flow control may be required to avoid laminar reattachment of the shear layer and to extend the use of the cavity design to even lower Reynolds numbers.

Wall Distance Effects on Transition to Turbulence in Low-Reynolds-Number Separated Flows

Scientific paper

Di Luca Matteo, Kenneth Breuer

AIAA Journal (American Institute of Aeronautics and Astronautics Journal), 2021 , vol. It will be published in the next available volume

Link to the publication

Summary:

Airfoils operating at Re<50,000 suffer from laminar separation that degrades aerodynamic efficiency. Transition to turbulence improves performance but becomes difficult to achieve at low Reynolds numbers. Experiments at separation Reynolds numbers, ReθS=24-46, with a rounded leading edge and a sharp back-step, were performed to distinguish between the effects of the wall proximity and Reynolds number on the shear layer transition to turbulence. When the shear layer is sufficiently far from the wall (HS>20), the transition distance, normalized by the model chord, is proportional to the Reynolds number at separation. The growth of instabilities are in good general agreement with both linear stability calculations based on the measured velocity profiles, and the predictions obtained using the computational tool XFOIL. For shape factors larger than 20, high growth rates occur, even for ReθS as low as 5. For smaller shape factors, instabilities are greatly reduced or eliminated, and the wall stabilizing effect becomes more significant as the Re number decreases. Guidelines for the design of turbulator devices are discussed.

2020

Design and Performance of an Ultra-Compact Low-Speed Low-Turbulence Level Wind Tunnel for Aerodynamic and Animal Flight Experiments

Scientific paper

Kenneth Breuer, Mark Drela, Xiaozhou Fan, Di Luca Matteo

AIAA AVIATION 2020 FORUM, 2020 , pp. 3107-3117

Link to the publication

Summary:

The paper presents a novel closed-circuit ultra-compact wind tunnel with an 8:1 contraction ratio and high flow quality. Its key design features include a 2D-type main diffuser, a minimum length contraction, and a screened expanding vane cascade in the last corner. These features reduce the overall tunnel footprint area to less than half of the area of a conventional tunnel design with the same test section size and same contraction ratio. The test section turbulence level is a very low 0.03% over a 4Hz–8500Hz bandwidth.

A bioinspired Separated Flow wing provides turbulence resilience and aerodynamic efficiency for miniature drones

Scientific paper

Di Luca Matteo, Stefano Mintchev, Yunxing Su, Eric Shaw, Kenneth Breuer

Science Robotics, 2020 , vol. 5, no 38

Link to the publication

Summary:

Small-scale drones have enough sensing and computing power to find use across a growing number of applications. However, flying in the low–Reynolds number regime remains challenging. High sensitivity to atmospheric turbulence compromises vehicle stability and control, and low aerodynamic efficiency limits flight duration. Conventional wing designs have thus far failed to address these two deficiencies simultaneously. Here, we draw inspiration from nature’s small flyers to design a wing with lift generation robust to gusts and freestream turbulence without sacrificing aerodynamic efficiency. This performance is achieved by forcing flow separation at the airfoil leading edge. Water and wind tunnel measurements are used to demonstrate the working principle and aerodynamic performance of the wing, showing a substantial reduction in the sensitivity of lift force production to freestream turbulence, as compared with the performance of an Eppler E423 low–Reynolds number wing. The minimum cruise power of a custom-built 104-gram fixed-wing drone equipped with the Separated Flow wing was measured in the wind tunnel indicating an upper limit for the flight time of 170 minutes, which is about four times higher than comparable existing fixed-wing drones. In addition, we present scaling guidelines and outline future design and manufacturing challenges.

2017

Bioinspired morphing wings for extended flight envelope and roll control of small drones

Scientific paper ArODES

Matteo Di Luca, Stefano Mintchev, Grégoire Heitz, Flavio Noca, Dario Floreano

Interface Focus, 2017, vol. 7, no. 1

Link to the publication

Summary:

Small-winged drones can face highly varied aerodynamic requirements, such as high manoeuvrability for flight among obstacles and high wind resistance for constant ground speed against strong headwinds that cannot all be optimally addressed by a single aerodynamic profile. Several bird species solve this problem by changing the shape of their wings to adapt to the different aerodynamic requirements. Here, we describe a novel morphing wing design composed of artificial feathers that can rapidly modify its geometry to fulfil different aerodynamic requirements. We show that a fully deployed configuration enhances manoeuvrability while a folded configuration offers low drag at high speeds and is beneficial in strong headwinds. We also show that asymmetric folding of the wings can be used for roll control of the drone. The aerodynamic performance of the morphing wing is characterized in simulations, in wind tunnel measurements and validated in outdoor flights with a small drone.

2020

Wall effects on the transition to turbulence in low Reynolds number separated flows

Conference

Di Luca Matteo, Kenneth Breuer

AIAA Scitech 2020 Forum, 06.01.2020 - 10.01.2020, Orlando

Link to the conference

Summary:

For small scale flying vehicles, which operate at Re numbers < 50; 000, airfoil efficiency is
greatly degraded and lift becomes very sensitive to external turbulence levels, surface roughness
and other disturbances. Separation is common in such flows, and laminar-to-turbulent
transition is required to close the separated bubble. To improve airfoil performance and reliability
at this low Re, transition to turbulence should be as fast as possible. The transition in
a low-Re separation zone is very sensitive to both environmental conditions and the presence
of the solid wall. Through the use of viscous linear stability theory and wind tunnel hot wire
measurements, we characterize the transition process of a shear layer separating at Reynolds
number (based on momentum thickness) 10. Although free shear layers are very unstable,
even at Re as low as 5, we find that the presence of a wall greatly reduces or eliminates shear
layer instabilities and, depending on the distance from the shear layer to the wall, the space
required for disturbance growth and laminar-to-turbulent transition can be greatly increased.

2019

Steady blowing to control the lift and drag on a free shear layer airfoil

Conference

Di Luca Matteo, Kenneth Breuer

AIAA SciTech 2019, 07.01.2019 - 11.01.2019, San Diego CA, United States

Link to the conference

Summary:

In an effort to improve the overall system performance of small subsonic Unmanned Aerial
Vehicles the use of flow control on a family of airfoils allowing separated flow is studied. The
airfoil consists of two flat plates, the shorter plate (flap) installed on top of the longer one and
at an angle. A steady wall jet emanates from a slot located close to the flap leading edge and
extending over the full wing span with the objective of increasing wing lift and reducing drag.
The lift and drag generated by the free shear layer wing have been measured experimentally at
low Reynolds numbers (26,000) and for different relative lengths and angles of the plates. Wind
tunnel lift measurements show that steady blowing increases the maximum lift of the airfoil
up to 2.8 while delaying stall. Without actuation, the high lift coefficients are obtained at high
angles of attack while steady blowing generates incremental lifts level slightly influenced by
the angle of attack. Steady blowing also reduces the drag coefficient at small angles of attack
while it is not effective at high angles of attack. The drag reduction at small angles of attack
is primarily due to a pressure reduction in the cavity between the plates and also to the thrust
generated by the jet.

Achievements

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Di Luca Matteo

Adjoint scientifique HES

Main skills

Aerodynamics

Programming & Algorithms

Engineering systems design

Business Management

Computer Aided Design

Recherche expérimentale

Adjoint scientifique HES