Unsteady Flow Diagnostics Laboratory

Laboratory

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

In this thesis, the aerodynamic challenges in flapping wing flight are addressed. In particular, the effects of different wing kinematics, flexibilities, and planforms on the the leading edge vortex development and aerodynamic performance are investigated. ...

According to the International Energy Agency, the global net-zero emissions objective requires the installed wind power capacity to increase 11-fold between 2020 and 2050. The scientific community has recently voiced concerns about the logistic feasibility ...

Vertical-axis wind turbines are excellent candidates to diversify wind energy technology, but their aerodynamic complexity limits industrial deployment. To improve the efficiency and lifespan of vertical-axis wind turbines, we desire data-driven models and ...

In this thesis, we explore the best practice of simulating the wakes of the turbines under active yaw control (AYC) using large-eddy simulation (LES). In the first study, we validate the blade-element actuator disk model (ADM-BE) for a yawed wind turbine. ...

The presence of aerodynamic vortices is widespread in nature. They can be found at small scales near the wing tip of flying insects or at bigger scale in the form of hurricanes, cyclones or even galaxies. They are identified as coherent regions of high vor ...

Vertical-axis wind turbines (VAWT) are excellent candidates to complement traditional wind turbines and increase the total wind energy capacity. Development of VAWT has been hampered by their low efficiency and structural unreliability, which are related t ...

Analytical wind turbine wake models are widely used to predict the wake velocity deficit. In these models, the wake growth rate is a key parameter specified mainly with empirical formulations. In this study, a new physics-based model is proposed and valida ...

Dynamic stall on airfoils negatively impacts their aerodynamic performance and can lead to structural damage. Accurate prediction and modelling of the dynamic stall loads are crucial for a more robust design of wings and blades that operate under unsteady ...

Biological flapping wing fliers operate efficiently and robustly in a wide range of flight conditions and are a great source of inspiration to engineers. The unsteady aerodynamics of flapping wing flight are dominated by large-scale vortical structures tha ...

Airfoil stall plays a central role in the design of safe and efficient lifting surfaces. We typically distinguish between static and dynamic stall based on the unsteady rate of change of an airfoil’s angle of attack. Despite the somewhat misleading denotat ...

Vertical axis wind turbines have several attractive features in the context of energy production in urban areas, but the inherent aerodynamic complexity of the flow around them has challenged their development on a larger scale. They generally operate at l ...

In this study, stereo particle imaging velocimetry measurements are performed at multiple streamwise locations behind a yawed wind turbine to reveal the formation mechanisms of the counter-rotating vortex pair (CVP), and a point vortex transportation (PVT) ...

A numerical framework for the aerodynamic characterization of wind turbine airfoils is developed and applied to the miniature wind turbine WiRE-01. The framework is based on a coupling between wall-resolved large eddy simulation (LES) and application of th ...

Unsteady flow separation in rotationally augmented flow fields plays a significant role in the aerodynamic performance of industrial rotors, including wind turbines. Current computational models underestimate the aerodynamic loads due to the inaccurate pre ...

Tip Vortex Cavitation (TVC) is a major issue in design and operation of axial hydraulic machines. We investigate the capacity of a flexible trailing thread in alleviating TVC by analyzing the flow-induced motion. For this purpose, a nylon thread with three ...

Dynamic stall dominates the aerodynamic performance, the robustness, and the wake dynamics of vertical axis wind turbines. To better assess the dynamic stall onset and its associated unsteady effects, this paper analyzes experimentally the evolution of the ...

Comprehensive wind tunnel experiments were carried out to study the interaction of a turbulent boundary layer with a wind turbine operating under different tip-speed ratios and yaw angles. Force and power measurements were performed to characterize the var ...

Insect flight is characterised by complex time-dependent flows in response to the unsteady wing movements. Biological fliers exploit the unsteady flow fields to modulate aerodynamic forces, thereby displaying unmatched flight performance, especially in hov ...

An optimized three-bladed horizontal-axis miniature wind turbine, called WiRE-01, with the rotor diameter of 15 cm is designed and fully characterized in Part I of this study. In the current part of the study, we investigate the interaction of the turbine ...

As wind turbines operate within the atmospheric boundary layer (ABL), the study of their interaction with the ABL flow can help us better understand and predict their performance. In addition to the performance of wind turbines, this interaction has an eff ...

Unsteady Flow Diagnostics Laboratory

Chat with Graph Search

The effects of kinematics, flexibility, and planform on the vortex formation and aerodynamic performance of flapping wing flight

Dynamic stall characterisation and control for vertical-axis wind turbines

Time scales of dynamic stall development on a vertical-axis wind turbine blade

Wind Turbine Wakes in Active Yaw Control: Numerical and Theoretical Studies

Growth, timing, & trajectory of vortices behind a rotating plate

The dynamic stall dilemma for vertical-axis wind turbines

A physics-based model for wind turbine wake expansion in the atmospheric boundary layer

All you need is time to generalise the Goman-Khrabrov dynamic stall model

Phenomenology and scaling of optimal flapping wing kinematics

The dynamics and timescales of static stall

Dynamic stall on an airfoil undergoing VAWT blade angle of attack variations

A point vortex transportation model for yawed wind turbine wakes

Numerical Framework for Aerodynamic Characterization of Wind Turbine Airfoils: Application to Miniature Wind Turbine WiRE-01

Coherent Structure Interaction During Unsteady Separation

Mitigating tip vortex cavitation by a flexible trailing thread

Critical evolution of leading edge suction during dynamic stall

Wind tunnel study of the wind turbine interaction with a boundary-layer flow: Upwind region, turbine performance, and wake region

Unsteady fluid dynamics around a hovering flat plate wing

A New Miniature Wind Turbine for Wind Tunnel Experiments. Part II: Wake Structure and Flow Dynamics

Interaction of atmospheric boundary layer flow with wind turbines : theoretical and experimental studies