Denis-Gabriel Caprace

• Doctor of Engineering
• PostDoc at UCLouvain

The angle of attack is widely used to describe the aerodynamics of rotor blades. Models based on lifting lines, actuator lines, and actuator disks use it as a primary variable, assuming the aerodynamics can be represented by the flow around a collection of equivalent 2D airfoils. This paper evaluates the accuracy of existing methods that extract th...

Ingenuity is considered the Martian equivalent of the Wright Flyer. Its sustained flights on Mars proved that non-terrestrial powered flight is possible, even on planets with thin atmospheres. However, Ingenuity was small and carried no payload. Future planetary rotorcraft will be bigger and heavier to accomplish new scientific and exploratory goal...

Recent advances in urban air mobility have driven the development of many new vertical take-off and landing (VTOL) concepts. These vehicles often feature original designs departing from the conventional helicopter configuration. Due to their novelty, the characteristics of the supervortices forming in the wake of such aircraft are unknown. However,...

A rotorcraft hovering near the ground causes downwash and outwash. The impact of these induced velocities on urban air mobility operations has not been extensively quantified. This paper explores the opportunity of using CFD to perform dedicated studies on the aerodynamics of rotorcraft in ground effect (IGE). For this purpose, we compare load and...

Reducing the cost of energy from wind power is a critical step towards decarbonizing the electric grid and mitigating climate change effects. Computational models are crucial in understanding the complex, multiphysics interactions of modern, highly flexible wind turbine rotors. When coupled with numerical optimization, such models provide an effici...

From small drones to large Urban Air Mobility vehicles, the market of vertical take-off and landing (VTOL) aircraft is currently booming. Modern VTOL designs feature a variety of configurations involving rotors, lifting surfaces and bluff bodies. The resulting aerodynamics are highly impacted by the interactions between those components and their w...

Recent advances in urban air mobility have driven the development of many new VTOL concepts. These vehicles often feature original designs and futuristic shapes. Due to their novelty, the wake characteristics of such aircraft are unknown. However, large wake-induced velocities, should they exist, may be dangerous for any other vehicle evolving in t...

The decarbonization of the electric grid is a fundamental technological and socio-economical challenge to address the looming threat of climate change. The reduction of the levelized cost of energy is a critical step to expand the application of carbon-free technologies that rely on high-potential, renewable energy sources such as wind power. Advan...

View Video Presentation: https://doi.org/10.2514/6.2022-1290.vid As demand grows for wind turbines with larger blades, the design of future wind turbines must account for multi-physical interactions and an ever-increasing number of design load conditions. One aspect, aerostructural coupling, calls for design tools that are both accurate and computa...

View Video Presentation: https://doi.org/10.2514/6.2022-1291.vid Multidisciplinary design optimization offers a comprehensive approach for designing complex aerostructural systems such as wind turbines. Gradient-based multidisciplinary design optimization can be used to optimize complex systems using large numbers of design variables. However, the...

In a fuel-efficient extended formation flight of commercial airplanes, the aerodynamic benefits depend on one’s ability to surf wake vortices. This paper presents a wake vortex detection scheme based on the exploitation of the aircraft flight dynamics measurements that effectively enables wake surfing. The study focuses on a two-aircraft formation...

In a fuel-efficient extended formation flight of commercial airplanes, the aerodynamic benefits depend on one's ability to surf wake vortices. This paper presents a wake vortex detection scheme based on the exploitation of the aircraft flight dynamics measurements, that effectively enables wake surfing. The study focuses on a two-aircraft formation...

A Fourier-based library of unbounded Poisson solvers (FLUPS) for 2D and 3D homogeneous distributed grids is presented. It is designed to handle every possible combination of periodic, symmetric, semi-unbounded, and fully unbounded boundary conditions for the Poisson equation on rectangular domains with uniform resolution. FLUPS leverages a dedicate...

Midway between a vortex method and a grid-based CFD, the Vortex Particle-Mesh method with Immersed Lifting Lines is intended to provide medium-fidelity results on rotor loadings, together with a realistic representation of the 3-D vortical wakes and their dynamics over long distances. We assess the potential of this hybrid approach for the Large-Ed...

Access to earthbound weightlessness is critical to many branches of applied sciences. Besides, several space systems require microgravity testing before their launch. Existing solutions (drop towers, parabolic flights, sounding rockets) offer variable durations and qualities of microgravity environment, but their cost and lead times make them unpra...

A framework performing Large Eddy Simulations of the flow past Floating Offshore Vertical Axis Wind Turbines (FOVAWT) mounted on semi-submersible platforms is presented. The simulation tool captures the unsteady flow and the resolved 6-DOF motion of the system. A state-of-the-art vortex particle-mesh method solves the aerodynamics and wakes of the...

When an object generates lift as a result of its motion through the air, it leaves a typical signature in its wake invariably featuring two parallel vortices. These structures are of great interest, both fundamentally considering their prevalence in fluid dynamics, and industrially for the critical impact they have on air traffic. This thesis is de...

We perform the large-eddy simulation of the flow past a helicopter rotor to support the investigation of rotorcraft wake characteristics and decay mechanisms. A hybrid Lagrangian-Eulerian Vortex Particle-Mesh method is employed to simulate the wake development, with the blades modeled using immersed lifting lines. The validity of the numerical appr...

The numerical study of the wake of full-scale slender devices such as aircraft wings and wind turbine blades requires high-fidelity large eddy simulation tools. The broad spectrum of scales involved entails the use of coarse-grain models for the devices. Actuator disk or line methods have been developed for that purpose, and are to date the most em...

A Fourier-based Library of Unbounded Poisson Solvers (FLUPS) for 2-D and 3-D homogeneous distributed grids is presented. It is designed to handle 3 every possible combination of periodic, symmetric, semi-unbounded and fully unbounded boundary conditions for the Poisson equation. FLUPS leverages a 4 dedicated implementation of 3-D Fourier transforms...

With the ever democratizing access to Space, easier access to microgravity before launch is becoming critical as more and more space systems are being developed and require testing. On the other hand, science and research continuously benefit from experiments conducted in reduced gravity environments. Conventional solutions to reach weightlessness...

Building on the well-known Prandtl lifting line, this work proposes an extended framework for mollified lifting lines, which is valid for multidimensional Gaussian smoothings. The smoothing length scale σ can be taken as constant or variable across the span. In this framework, slender lifting device and its wake are represented by a mollified vorte...

The present work focuses on the Large Eddy Simulation of the wake flow behind an advancing rotor, to support the investigation of rotorcraft wake characteristics and decay mechanisms. A mixed Lagrangian-Eulerian Vortex Particle-Mesh (VPM) method was employed to simulate the near to far wake development of a four-bladed rotor. The rotor configuratio...

The present work focuses on the Large Eddy Simulation of the wake flow behind an advancing rotor, to support the investigation of rotorcraft wake characteristics and decay mechanisms.

A vortex particle-mesh (VPM) method with immersed lifting lines has been developed and validated. Based on the vorticity–velocity formulation of the Navier–Stokes equations, it combines the advantages of a particle method and of a mesh-based approach. The immersed lifting lines handle the creation of vorticity from the blade elements and its early...

The aerodynamics of Vertical Axis Wind Turbines (VAWTs) is inherently unsteady, which leads to vorticity shedding mechanisms due to both the lift distribution along the blade and its time evolution. In this paper, we perform large-scale, fine-resolution Large Eddy Simulations of the flow past Vertical Axis Wind Turbines by means of a state-of-the-a...

A Vortex Particle-Mesh (VPM) method with immersed lifting lines has been developed and validated. Based on the vorticity-velocity formulation of the Navier-Stokes equations, it combines the advantages of a particle method and of a mesh-based approach. The immersed lifting lines handle the creation of vorticity from the blade elements and its early...

A Vortex Particle-Mesh (VPM) method with immersed lifting lines has been developed and validated. Based on the vorticity-velocity formulation of the Navier-Stokes equations, it combines the advantages of a particle method and of a mesh-based approach. The immersed lifting lines handle the creation of vorticity from the blade elements and its early...

A Vortex Particle-Mesh (VPM) method with immersed lifting lines has been developed and validated. Based on the vorticity-velocity formulation of the Navier-Stokes equations, it combines the advantages of a particle method and of a mesh-based approach. The immersed lifting lines handle the creation of vorticity from the blade elements and its early...

A Vortex Particle-Mesh (VPM) method with immersed lifting lines (ILL) has been developed and validated, in a HPC framework. The vorticity-velocity formulation of the Navier-Stokes equations is treated in a hybrid way: particles handle advection while the mesh is used to evaluate the differential operators and for the fast Poisson solvers (here a Fo...