William Wolf
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View article: Interplay between streaks and vortices in shock-boundary layer interactions with conditional bubble events over a turbine airfoil
Interplay between streaks and vortices in shock-boundary layer interactions with conditional bubble events over a turbine airfoil Open
The shock-boundary layer interaction over the convex wall of a supersonic turbine vane is studied with a focus on extreme separation bubble events and the interplay between the bubble, streaks, and streamwise vortices. The present analysis…
View article: Resultant Force on Grains of a Real Sand Dune: How to Measure It?
Resultant Force on Grains of a Real Sand Dune: How to Measure It? Open
Barchan dunes usually appear under the action of one‐directional fluid flows, being found on Earth, Mars, and other celestial bodies; however, although ubiquitous in nature, understanding dune dynamics at the grain scale is challenging due…
View article: Pressure Field Reconstruction with SIREN: A Mesh-Free Approach for Image Velocimetry in Complex Noisy Environments
Pressure Field Reconstruction with SIREN: A Mesh-Free Approach for Image Velocimetry in Complex Noisy Environments Open
This work presents a novel approach for pressure field reconstruction from image velocimetry data using SIREN (Sinusoidal Representation Network), emphasizing its effectiveness as an implicit neural representation in noisy environments and…
View article: Duty-cycle actuation for drag reduction of deep dynamic stall: Insights from linear stability analysis
Duty-cycle actuation for drag reduction of deep dynamic stall: Insights from linear stability analysis Open
A flow control framework based on linear stability analysis is proposed focusing on reducing the aerodynamic drag due to dynamic stall through a finite-window temporal actuation. The methodology is applied on a periodically plunging SD7003…
View article: Intermittency of a transitional airfoil flow with laminar separation bubble solved by the lattice-Boltzmann method
Intermittency of a transitional airfoil flow with laminar separation bubble solved by the lattice-Boltzmann method Open
The flow over a NACA0012 airfoil at a moderate Reynolds number Re = 50,000 and angle of attack of alpha = 3 degrees is investigated using the lattice-Boltzmann method (LBM). The LBM solutions are computed in direct numerical simulation (DN…
View article: Characterization of Boundary Layers on Isothermal and Adiabatic Curved Surfaces of a Supersonic Turbine Cascade
Characterization of Boundary Layers on Isothermal and Adiabatic Curved Surfaces of a Supersonic Turbine Cascade Open
The effects of adiabatic and isothermal boundary conditions are investigated on the shock-boundary layer interactions (SBLIs) in a supersonic turbine cascade. Special attention is given to the characterization of the incoming boundary laye…
View article: Mach number effects on shock-boundary layer interactions over curved surfaces of supersonic turbine cascades
Mach number effects on shock-boundary layer interactions over curved surfaces of supersonic turbine cascades Open
The effects of inlet Mach number on the unsteadiness of shock-boundary layer interactions (SBLIs) over curved surfaces are investigated for a supersonic turbine cascade using wall-resolved large eddy simulations. Three inlet Mach numbers, …
View article: Embedded shear layers in turbulent boundary layers of a NACA0012 airfoil at high angles of attack
Embedded shear layers in turbulent boundary layers of a NACA0012 airfoil at high angles of attack Open
An investigation of turbulent boundary layers (TBLs) is presented for a NACA0012 airfoil at angles of attack 9 and 12 deg. Wall-resolved large eddy simulations (LES) are conducted for a freestream Mach number M = 0.2 and chord-based Reynol…
View article: Analysis of transient and intermittent flows using a multidimensional empirical mode decomposition
Analysis of transient and intermittent flows using a multidimensional empirical mode decomposition Open
Modal decomposition techniques are important tools for the analysis of unsteady flows and, in order to provide meaningful insights with respect to coherent structures and their characteristic frequencies, the modes must possess a robust sp…
View article: Neural networks in feedback for flow analysis, sensor placement and control
Neural networks in feedback for flow analysis, sensor placement and control Open
This work presents a novel methodology for analysis and control of nonlinear fluid systems using neural networks. The approach is demonstrated on four different study cases being the Lorenz system, a modified version of the Kuramoto-Sivash…
View article: Analysis of transient and intermittent flows using a multidimensional empirical mode decomposition
Analysis of transient and intermittent flows using a multidimensional empirical mode decomposition Open
Modal decomposition techniques are important tools for the analysis of unsteady flows and, in order to provide meaningful insights with respect to coherent structures and their characteristic frequencies, the modes must possess a robust sp…
View article: Acoustic radiation of a simplified jet-flap-thrust gate configuration: numerical and experimental investigation
Acoustic radiation of a simplified jet-flap-thrust gate configuration: numerical and experimental investigation Open
A comparative study of the acoustic far-field radiation of a subsonic jet near a folded plate with an opening, intended to represent a flapped wing with thrust gate, is presented in this work. Three openings with different widths were used…
View article: Flow imaging as an alternative to pressure transducers through vision transformers and convolutional neural networks
Flow imaging as an alternative to pressure transducers through vision transformers and convolutional neural networks Open
In this work, we propose a framework whereby flow imaging data is leveraged to extract relevant information from flowfield visualizations. To this end, a vision transformer (ViT) model is developed to predict the unsteady pressure distribu…
View article: Unsteadiness of shock-boundary layer interactions in a Mach 2.0 supersonic turbine cascade
Unsteadiness of shock-boundary layer interactions in a Mach 2.0 supersonic turbine cascade Open
The physics of shock-boundary layer interactions (SBLIs) in a supersonic\nturbine cascade at Mach 2.0 and Reynolds number 395,000, based on the axial\nchord, is investigated through a wall-resolved large eddy simulation. Special\nattention…
View article: Switch of tonal noise generation mechanisms in airfoil transitional flows
Switch of tonal noise generation mechanisms in airfoil transitional flows Open
Large eddy simulations are performed to study tonal noise generation by a NACA0012 airfoil at an angle of attack ${\alpha = 3}$ deg. and freestream Mach number of ${M_{\infty} = 0.3}$. Different Reynolds numbers are analyzed spanning ${0.5…
View article: Comparison of Shock-Boundary Layer Interactions in Adiabatic and Isothermal Supersonic Turbine Cascades
Comparison of Shock-Boundary Layer Interactions in Adiabatic and Isothermal Supersonic Turbine Cascades Open
Wall-resolved large eddy simulations are employed to investigate the shock-boundary layer
\ninteractions (SBLIs) in a supersonic turbine cascade. An analysis of the suction side separation
\nbubbles forming due to the SBLIs is presented fo…
View article: Analysis of the onset and evolution of a dynamic stall vortex on a periodic plunging aerofoil
Analysis of the onset and evolution of a dynamic stall vortex on a periodic plunging aerofoil Open
The onset and evolution of the dynamic stall vortex (DSV) are analysed by means of large eddy simulations of an SD7003 aerofoil undergoing periodic plunging motion in a transitional Reynolds number flow ( $Re =6\times 10^{4}$ ). Interactio…
View article: Transition, intermittency and phase interference effects in airfoil secondary tones and acoustic feedback loop
Transition, intermittency and phase interference effects in airfoil secondary tones and acoustic feedback loop Open
A large eddy simulation is performed to study secondary tones generated by a NACA0012 airfoil at angle of attack of $\alpha = 3^{\circ}$ with freestream Mach number of $M_{\infty} = 0.3$ and Reynolds number of $Re = 5 \times 10^4$ . Lamina…
View article: Edge modes and dressing fields for the Newton-Cartan quantum Hall effect
Edge modes and dressing fields for the Newton-Cartan quantum Hall effect Open
It is now well-known that Newton-Cartan theory is the correct geometrical setting for modelling the quantum Hall effect. In addition, in recent years edge modes for the Newton-Cartan quantum Hall effect have been derived. However, the exis…
View article: On the application of incomplete FWH surfaces for aeroacoustic predictions
On the application of incomplete FWH surfaces for aeroacoustic predictions Open
This work is motivated by CFD simulations from a realistic landing gear performed modeling only the half bottom of the aircraft fuselage [15]. Hence, in this previous analysis, the aeroacoustic predictions had to employ incomplete FWH surf…
View article: Model reduction of traveling-wave problems via Radon cumulative distribution transform
Model reduction of traveling-wave problems via Radon cumulative distribution transform Open
Traveling-wave problems, due to their sizable Kolmogorov n-width, have brought critical challenges to conventional model reduction techniques. This study aims to provide insights into this problem by exploiting the Radon cumulative distrib…
View article: Extremum seeking control applied to airfoil trailing-edge noise suppression
Extremum seeking control applied to airfoil trailing-edge noise suppression Open
Extremum seeking control (ESC) and its slope seeking generalization are applied in a high-fidelity flow simulation framework for reduction of acoustic noise generated by a NACA0012 airfoil. Two Reynolds numbers are studied for which differ…
View article: The role of transition, intermittency and phase interference in airfoil secondary tones
The role of transition, intermittency and phase interference in airfoil secondary tones Open
A wall-resolved large eddy simulation is performed to study secondary tones generated by a NACA0012 airfoil at $\alpha = 3^{\circ}$ with freestream Mach number $M_{\infty} = 0.3$ and Reynolds number $Re = 5 \times 10^4$. Laminar separation…
View article: Data-Driven Closure of Projection-Based Reduced Order Models for\n Unsteady Compressible Flows
Data-Driven Closure of Projection-Based Reduced Order Models for\n Unsteady Compressible Flows Open
A data-driven closure modeling based on proper orthogonal decomposition (POD)\ntemporal modes is used to obtain stable and accurate reduced order models\n(ROMs) of unsteady compressible flows. Model reduction is obtained via Galerkin\nand …