Yannick Hoarau

• PhD
• Professor (Full) at University of Strasbourg

The importance of modelling two-phase flows involving shock waves arises from many engineering and medical applications. The presence of strong shock waves and their interactions with bubble interfaces, the high density ratio between phases and the large variation of material properties makes the resolution of such problems a complicated task for t...

The present study investigates by means of numerical simulation the effects of a morphing concept modeled through a spanwise travelling wave (STW) applied in the near trailing edge region of an A320 wing in the low subsonic regime. This concept is part of the bioinspired electroactive morphing studies carried out in the context of the European rese...

In this research article, we present the formulation and implementation of various correlation-based transition models within the framework of an in-house CFD solver, NSMB. The models considered include the zero-equation BCM (Bas-Cakmakcioglu with Modifications) model, the one-equation \(\gamma \) model, and the two-equation \(\gamma \)-Re\(_{\thet...

This study presents an investigation of an innovative microfluidic flow separator using both numerical and experimental approaches to calibrate contrast‐enhanced ultrasound scanners. Numerical simulations were conducted using Lagrangian particles tracking and passive scalar transport methodologies using the OpenFOAM software. The experimental valid...

Bioinspired electroactive morphing is investigated around an A320 wing at high Reynolds number in subsonic regime by applying slight deformations and vibrations in the near trailing edge region. The effects of morphing on the aerodynamic performance are studied numerically using the Navier Stokes Multi-Block (NSMB) code on the \(70\, {\text{cm}}\)...

This study concerns a numerical investigation of new morphing concepts by means of high-fidelity simulation around a high-lift wing-flap system and a real scale Airbus A320 airplane. A new designed hybrid morphing flap is proposed based on cambering at high deformation amplitudes associated with trailing-edge flapping at an actuation frequency in t...

Purpose This study aims to investigate the morphing concepts able to manipulate the dynamics of the downstream unsteadiness in the separated shear layers and, in the wake, be able to modify the upstream shock–boundary layer interaction (SBLI) around an A320 morphing prototype to control these instabilities, with emphasis to the attenuation or even...

A laminar separation bubble (LSB) occurs when the flow separates in the laminar regime. The turbulence developing inside the re-circulation region enhances the momentum transport and the flow re-attaches. The laminar separation bubble is one of the main critical aspects of flows at low Reynolds number, of order of magnitude $10^4$-$10^5$, but resul...

The study described in this paper was conducted as part of the European Funded CleanSky2 project AFC4TR (Active Flow Control for Tilt-Rotor aircraft). High-Fidelity numerical simulations were made to study various approaches of using Active Flow Control (AFC) actuators to delay flow separation at near stall conditions of the Next Generation Civil T...

Background The DCE‐US (Dynamic Contrast‐Enhanced Ultrasonography) imaging protocol predicts the vascular modifications compared with Response Evaluation Criteria in Solid Tumors (RECIST) based mainly on morphological changes. A quantitative biomarker has been validated through the DCE‐US multi‐centric study for early monitoring of the efficiency of...

Purpose This study aims to investigate the physical mechanisms of the use of active flow control (AFC) for a high-lift wing-flap configuration. Design/methodology/approach By means of high-fidelity numerical simulations, the flow dynamics around a high-lift wing-flap system at high Reynolds number (Re/c = 4.6 million) is studied. Adapted turbulenc...

Purpose This study aims to investigate the effects of electroactive morphing on the Airbus A320 Reduced Scale prototype of the H2020 N° 723402 European Research project smart morphing and sensing (SMS) for aeronautical configurations [1] , [2]. Design/methodology/approach The flow regimes correspond to low subsonic take-off conditions. The morphin...

In this chapter, the physical analysis and optimisation of the morphing behaviour have been performed by means of numerical High-Fidelity (Hi-Fi) fluid-structure interaction simulations. The most advanced turbulence modelling approaches in the context of CFDSM (Computational Fluid Dynamics Structural Mechanics) have been used. This effort had as ma...

This article presents a synthesis of main results from the H2020 European Research project N 723,402 “Smart Morphing and Sensing for Aeronautical Configurations”, www.smartwing.org/SMS/EU concerning the design of disruptive wing configurations able to considerably increase the aerodynamic performances compared to conventional designs. This is achie...

The flow around the Leonardo Next-Generation Civil Tiltrotor aircraft (NGCTR-TD) is examined in the European research programme CleanSky AFC4TR 'Active Flow Control for Tilt-Rotor aircraft" N° 886718, with the main objective to investigate the use of Active Flow Control Zero Net Mass Flux (ZNMF). This work focuses on the optimization of different p...

Two diffuse interface models for compressible two-phase flows including phase transfer are presented. The first one is based on conservation laws for mixture variables with an additional equation for the void ratio in which the mass transfer appears explicitly in the source term. The second one is fully conservative and a relaxation model is built...

This study aims to investigate the flow around a morphing wing [1,2] at high Reynolds number 1M and angle of attack of 10°. A separation of the boundary layer occurs at approximately 80% of the chord towards the trailing-edge (figure 1). Therefore, a formation of strong shearing downstream in the wake leading a the development of the von Kármán vor...

View Video Presentation: https://doi.org/10.2514/6.2022-3238.vid This paper discusses the physical dynamics of the use of the Active Flow Control (AFC) actuators embedded in a Vertical Take-Off and Landing (VTOL) aircraft. Results of High-Fidelity numerical simulations are examined at near stall conditions. Different approaches of AFC are proposed...

This study examines the physical dynamics of the use of the Active Flow Control (AFC) devices embedded inside a high-lift configuration wing-flap system. The flap is highly deflected and cambered using morphing surfaces, a separation of the flow occurs at approximately 60 % of the flap's chord leading to an important loss of the aerodynamic efficie...

This study aims to investigate the flow around a morphing wing [1,2] at high Reynolds number 1M and angle of attack of 10°. A separation of the boundary layer occurs at approximately 80% of the chord towards the trailing-edge (figure 1). Therefore, a formation of strong shearing downstream in the wake leading the development of the von Kármán vorte...

This study examines the physical dynamics of the use of the Active Flow Control (AFC) devices embedded inside a high-lift configuration wing-flap system. The flap is highly deflected and cambered using morphing surfaces, a separation of the flow occurs at approximately 60 % of the flap's chord leading to an important loss of the aerodynamic efficie...

The maneuvering simulation is carried out through the continuous captive model test and the system dynamics approach. The mathematical maneuvering group (MMG) model is implemented in the virtual captive model tests by using the computational fluid dynamics (CFD) techniques. The oblique towing test (OTT), the circular motion test (CMT), the rudder f...

A strongly coupled algorithm is presented for the incompressible fluid-rigid body interaction using the moving immersed boundary method. The pressure and the boundary force are treated as Lagrange multipliers to enforce the incompressibility and no-slip wall constraints. To compute the two unknowns from the velocity field, we adopt the fractional s...

The average and unsteady hydrodynamics of an inland convoy passing bridge piers in a confined waterway were investigated using both numerical and experimental approaches. The numerical simulations are realized by solving the RANS (Reynolds-averaged Navier–Stokes) equations accounting for the solid body motion using the sliding mesh technique, while...

This study investigates high-fidelity numerical simulation of 3D flow around the Reduced-Scale (RS) prototype used in the H2020 N° 723402 : ”Smart Morphing & Sensing” (SMS) European project, in take-off conditions corresponding to the low subsonic regime. Morphing employing trailing edge actuations in the frequency range of (100-400) Hz associated...

This study investigates the physical mechanisms of the use of Active Flow Control (AFC) associated with morphing and the cambering approach in a high-lift wing-flap system. Results of high-fidelity numerical simulations are examined at high Reynolds number (Re/c) of 4.6 Million. Adapted turbulence models are used to capture the flow separation and...

Wing morphing as a means to continuously modify wing geometry is employed in a numerical simulation in order to act upon aerodynamic performance in cruise flight. In this flight regime, the interaction of a shock wave and boundary layer instabilities can lead to transonic buffet, the coordinated motion of both the shock and the detached boundary la...

The principal aim of this paper is to investigate the numerical effects of a deformable flap by means of a quasi-static cambering following an Airbus A320 designed prototype in the Smart Morphing and Sensing European project. This prototype able to camber by means of the Electro-Mechanical Actuators (EMA) to achieve high amplitude deformation up to...

This article examines the aerodynamic performance in- crease by means of high-Fidelity simulations using ef- ficient and adapted turbulence modelling approaches at high Reynolds numbers. The application concerns a wing/flap high-lift configuration as well as a full Airbus airplane in the context of the H2020 European research project SMS ”Smart Mor...

This article examines the morphing effect of trailing-edge flap of high lift configuration at the take-off position. It includes vibrations with different frequencies and amplitudes around the supercritical Airbus A320 wing-flap. The Reynolds number is 2.25 million and the angle of attack 8.2° which corresponds to take-off and landing phases. The f...

The flow dynamics and their morphing modification concerning the transonic flow around an Airbus A320 airfoil have been investigated via 2D simulations at a high Reynolds number. A distinctive flow topology, organised and chaotic occurs in this regime driven by appearance of coherent structures such as the Von-Kármán instability as well as the Kelv...

This study analyses by means of High-Fidelity numerical simulation the increase of aerodynamic performances of a morphing wing-flap configuration of an A3xx type in take-off conditions. The electroactive morphing has been realized by novel actuators embedded under the “skin” of the lifting structure and are able to optimally deform and vibrate the...

This study illustrates the morphing effects around a large-scale high-lift configuration of the Airbus A320 with two element airfoil-flap in take-off configuration, in the context of the Smart Morphing and Sensing European project (www.smartwing.org/SMS/EU). The flow around the wing and its near wake is analysed in respect of slight deformation and...

By actuating the rear part of a wing at amplitudes and frequencies belonging to optimal ranges, Jodin et al. (2017) have shown through experiments that the lift generated by a wing can be increased and its drag decreased when combining high-frequency and low-amplitude vibrations with low-frequency and high-amplitude cambering motion of the trailing...

Study of transition location effect (from natural transition to fully turbulent) on separation size, shock structure and unsteadiness was the focus of this WP. Boundary layer tripping (by wire or roughness) and flow control devices (VG) were used for boundary layer transition induction. Although this type of flow field had been studied widely in th...

In order to be able to judge the effectiveness of transition induction in WP-2, reference flow cases were planned in WP-1. There are two obvious reference cases—a fully laminar interaction and a fully turbulent interaction. Here it should be explained that the terms “laminar” and “turbulent” interaction refer to the boundary layer state at the begi...

We study the numerical solution to two-phase problems using a four-equations model. In particular we focus the present study on HLLC numerical flux approximation and its extensions. These numerical methods are tested on expansion tube cases with a final goal of constructing higher order hybrid numerical tool for solving the problem of bubble collap...

The numerical investigation of free radical polymerization (FRP) of methyl methacrylate under mixed feed condition at inlet is made for three microtubular reactor geometries, namely, straight tube, coiled tube, and coil flow inverter reactor. The effect of variation of fluid thermophysical properties (FTPP) (density, viscosity, and thermal conducti...

We study the numerical methods to solve stiff two-phase flow problem which involves strong shock and expansion waves. In particular we focus the present study on high order reconstruction techniques coupled with HLLC and KNP numerical flux formulations associated to a four-equation model. These numerical methods are first tested on 1-D expansion tu...

Two tubular microreactor geometries—straight tube reactor (STR) and coil flow inverter reactor (CFIR)—are numerically studied with unmixed feed condition for the synthesis of poly(methyl methacrylate) and poly(styrene) by free radical polymerization. A new transformation rendering model dimensionless in terms of concentration is used during computa...

The present study concerns the use of unsteady numerical simulations by means of Navier Stokes Multi Block (NSMB) solver including both high order schemes and turbulence resolving methods. Firstly, this work attempts to highlight the role of the morphing applied to the supercritical Airbus A320 wing and flap in the trailing-edge for a Reduced Scale...

This book gathers the proceedings of the Seventh Symposium on Hybrid RANS-LES Methods, which was held on September 17-19 in Berlin, Germany. The different chapters, written by leading experts, reports on the most recent developments in flow physics modelling, and gives a special emphasis to industrially relevant applications of hybrid RANS-LES meth...

This article presents numerical simulation results obtained in the context of the H2020 European research project SMS, “Smart Morphing and Sensing for Aeronautical configurations” by using among other, hybrid RANS-LES methods, able to accompany the design of the wings of the future. The morphing concepts studied are partly bio-inspired and are able...

Purpose The purpose of this study illustrates the morphing effects around a large-scale high-lift configuration of the Airbus A320 with two elements airfoil-flap in the take-off position. The flow around the airfoil-flap and the near wake are analysed in the static case and under time-dependent vibration of the flap trailing-edge known as the dynam...

The present study concerns the use of unsteady numerical simulations by means of Navier Stokes Multi Block (NSMB) solver including both high order schemes and turbulence resolving methods. Firstly, this work attempts to highlight the role of the morphing applied to the supercritical Airbus A320 wing and flap in the trailing-edge for a Reduced Scale...

A Galerkin-free model reduction approach for fluid-structure interaction (FSI) is presented in this article. The reduced order model (ROM) is based on proper orthogonal decomposition (POD), where a reduced basis is formed using energy dominant POD modes. The reduced basis also consists of characteristics POD time modes that are derived from the POD...

This article examines the morphing effects of the trailing-edge deformation and vibration on the turbulent structures in the wake of a supercritical Airbus-320 wing. It is shown that the electroactive morphing has the capacity to produce an enhanced aerodynamic performance (lift increase, drag reduction) and reduce the amplitude of instability mode...

Ice accretion in aircraft structures is modelled using the Level-Set method. Due to the nature of the evolving ice shape and the re-meshing complexity, current icing models are limited. The Level-Set method allows fully multi-step simulation of ice accretion. The solid boundary is treated implicitly or explicitly. The solid body can be defined via...

Ice accumulation in aircraft is modelled using the Level-Set method. Current two-dimensional and three-dimensional icing models are limited regarding complex re-meshing due to ice accretion. The Level-Set method allows fully multi-step simulation of ice accretion. The solid boundary is treated implicitly or explicitly. The solid body can be defined...

This article examines the aerodynamic performance increase of an Airbus A320 aerofoil thanks to morphing of the near-trailing-edge region in transonic regime corresponding to cruise conditions. The study has been carried out by numerical simulation at Reynolds number Re=2.06×10 ⁶ and Mach number of 0.78, by using the NSMB code (Navier–Stokes MultiB...

This study illustrates the morphing effects around a large-scale high-lift configuration with one/two element airfoil-flap in the clean and take-off positions. Firstly, experimental results obtained in the subsonic wind tunnel S1 of IMFT are discussed with High-Fidelity numerical results obtained by using the NSMB (Navier-Stokes Multiblock) code wi...

This paper presents a numerical study of the interaction between a planar incident shock wave with a cylindrical gas bubble. Simulations are performed using an inviscid compressible one-fluid solver based upon three conservation laws for the mixture variables, namely mass, momentum, and total energy along with a supplementary transport equation for...

This study analyses the fluid-elastic instability occurring in turbulent wakes around tandem cylinders as well as the morphing effect in order to control the instability amplification and to improve the aerodynamic performances particularly concerning the Airbus-A320 wing-flap configuration. These studies have been carried out by means of High-Fide...

Mini-invasive surgery is an important progress for patient comfort, success rate, and complication decrease, although, simultaneously, it increases drastically the complexity of the surgeon work. As the visualization went from the view of the real physical organ to 2D flat screens, this induced a loss of information, as well as a reduction of the v...

The present study concerns the use of high-fidelity numerical simulations by mean of NSMB code. Firstly, this work attempts to highlight the role of the morphing applied to the supercritical Airbus A320 wing and flap in the trailing-edge for a reduced scale RS prototype at the clean position, this morphing includes a slight deformation of the trail...

Medical applications require the numerical models to be both precise and quickly computed. In the context of liver surgery, this study aims to develop a homogenized mechanical model of the liver accounting for both hepatic tissue properties and macroscopic level blood flow impact. For this, a fluid analysis is carried out to simulate the blood flow...

A six-Dof motion solver based on unit quaternions and an actuator disk model are implemented for ship hydrodynamics predictions. The six-Dof module is tested using the water entry phenomenon of a free falling sphere. The displacement history and impacting forces are analyzed. A KCS (KRISO container ship) model with the allowances of sinkage and tri...

The use of numerical models for surgery applications to provide 3D information in real time through augmented reality helps surgeons making the right decisions. These models require to be at the same time quick, precise, and to integrate patient dependence. Until know, real-time resolution software used to sacrifice real physics and precision to be...

A high-lift flap is used to improve the take-off and landing aerodynamic performance of aircraft. This study is a part of electroactive morphing activities in the context of the SMS (Smart Morphing and Sensing) European project (www.smartmorphing.org/SMS) .It includes numerical simulations and physical analysis issued from the hybrid morphing, oper...

This contribution examines the effect of trailing-edge region deformation and vibration on the turbulent structures on the turbulent structures developing around and in the wake of a supercritical Airbus-320 wing. The Reynolds number was 1 Million in the study is carried out in the low subsonic regime at an incidence angle of 10o, corresponding to...

Wing morphing has been a major subject of research since the dawn of Aerodynamics, with early works by Von K´arm´an and Burgers (1936) or Garrick (1937) aiming at understanding the way a flapping airfoil interacts with the turbulent flow. A great deal of studies have been devoted to this topic since then. Concerning more recent studies which derive...

Purpose This paper assesses the strengths and weaknesses of four thermodynamic models used in aircraft icing simulations to orient the development or the choice of an improved thermodynamic model. Design/methodology/approach Four models are compared to assess their capabilities: Messinger, Iterative Messinger, Extended Messinger and Shallow Wate...

This article examines the morphing effects of the trailingedge deformation and vibration on the turbulent structures in the wake of a supercritical Airbus-320 wing. The Reynolds number was 1 Million. The study is carried out in the low subsonic regime at an incidence angle of 10o, corresponding to take-off/landing flight phases. The morphing effect...

Aircraft ice accretion is modelled through a Level-Set framework. Current two-dimensional and 3D icing models do not reply to current needs. The level-set framework permits a fully multi-step ice accretion simulation. The solid boundary is treated implicitly by a penaliza-tion method or an immersed boundary method (IBM)-LS. Wherein, the solid body...

The present paper details the simulations carried out for the 3D-V2C wing configuration designed by Dassault Aviation in the context of the TFAST—Transition location effect on shock boundary layer interaction—European programme. The results concern the constant section wing and the swept one. In the second case, the transition location is imposed b...

Large eddy simulations (LES) of a single phase water flow through a square normal tube bundle at Reynolds numbers from 2000 to 6000 is performed to investigate the fluid-elastic instability. A single cylinder of the array is allowed to oscillate in one degree of freedom (1-DOF) in the flow normal direction, similar as in the corresponding experimen...

An experimental approach involving electron paramagnetic resonance is proposed for studying photo-generated reactive species in semiconductor nano-particle-based films deposited on the internal wall of glass capillaries. This methodology is applied here to nano-TiO2 and allows a semi-quantitative analysis of the kinetic evolutions of radical produc...

This book reports on the latest developments in computational fluid dynamics and turbulence modeling, with a special emphasis on hybrid RANS-LES methods and their industrial applications. It gathers the proceedings of the Sixth Symposium on Hybrid RANS-LES Methods, held on September 26-28 in Strasbourg, France. The different chapters covers a wealt...

In the context of mechanobiology of soft tissue, numerical models have the advantages of providing information that will help all people in need of predictive tools to bridge the physiological biology and solid physics. More specifically, in the context of mini-invasive tumor surgery of the liver, real time augmented reality provide the surgeon wit...

The Level-Set (LS) framework is introduced to model the ice accretion on aircraft structures. Widelyused two-dimensional and 3D icing models fail to preserve and reply to current needs. The level-setdisposition permitted a fully multiple layer ice accretion model : multi-step ice accretion simulation.Wherein, the solid boundary is treated by a pena...

In the context of soft tissue mechanobiology, numerical models have the advantages of providing information that will help physicians, biologists, mechanicians, surgeon and more generally all people in need of predictive tools to bridge the physiological biology and solid physics. More specifically, for mini-invasive surgery of liver tumor resectio...

This study analyses the fluid-elastic instability occurring in turbulent wakes around tandem cylinders as well as the morphing effect in order to control the instability amplification and to improve the aerodynamic performances particularly concerning the Airbus-A320 wing-flap configuration. These studies have been carried out by means of High-Fide...

The features of a Newtonian-fluid flow in a two-dimensional channel with sudden contraction and expansion are investigated by numerical modeling. The kinetics of the bifurcation transition from the symmetric mode to steady-state asymmetric flow on the outlet from the zone of contraction of the channel is analyzed. The linear dependence of the degre...

A novel implicit immersed boundary method of high accuracy and efficiency is presented for the simulation of incompressible viscous flow over complex stationary or moving solid boundaries. A boundary force is often introduced in many immersed boundary methods to mimic the presence of solid boundary, such that the overall simulation can be performed...

A novel immersed boundary method is introduced for simulating the fluid-structure interaction problem. Unlike the body-conforming mesh method which imposes the no-slip boundary conditions directly on the immersed interface, the immersed boundary method adopts a boundary force for the presence of the immersed solid. Therefore, the fluid is simply si...

The study undertaken in this article is to develop a reliable and comprehensive numerical modelling of particle transport in pulmonary flow based on the use of CFD-ACE code of commercial calculation. This code includes a fluid solver that solves the Navier-Stokes in a finite volume formulation. The CFD-GEOM software was used to create the 3D surfac...

A new approach using the Level-Set framework is developed in the NSMB (Navier–Stokes-multi-block) compressible solver for modeling the ice/air interface evolution through time during in-flight icing. Droplet distribution and impingement efficiency are computed by an Eulerian approach and the accreted ice is calculated by a PDE model. An icing veloc...

The numerical analysis of the mechanisms governing the flow in a porous region is of priority interest for modelling porous media flows. The present study describes an adapted and efficient turbulence modelling technique for this category of porous media flows. The main objective of the present study is to provide a detailed pore scale description...

We consider well-developed inhomogeneous turbulent shear flows in the x direction that are bounded by interfaces (I) separating regions of turbulent and non-turbulent (or weak turbulent) flows. The interfaces are approximately continuous and there is no large-scale forcing (by body forces or external turbulence) in these flows, see Fig. 1.

This paper addresses the topic of the influence of the profile of a plate on a turbulent flow. The study is based on numerical results obtained by URANS and hybrid (DDES) turbulence modeling and compared with experimental results. The flat plate has an aspect ratio of 20 (length over thickness) and the edges are not smoothed. The plate includes Sha...

In this study the focus is made on the properties of the bistable flow between two cylinder in tandem for a pitch ratio \(L/D = 3.7\) at a Reynolds number of 132,800. Time resolved particle image velocimetry (TRPIV) is used to measure the spatial distribution and time fluctuations of the velocity field in the wake of the upstream cylinder. From vel...

We present an implicit immersed boundary method via operator splitting technique for simulating fluid flow over moving solid with complex shape. An additional moving force equation is derived in order to impose the interface velocity condition exactly on the immersed surface. The moving force matrix is formulated to be symmetric and positive defini...

An icing model is developed in the Navier-Stokes multi-block (NSMB) compressible solver. The code implemented in this study is based on an Eulerian formulation for droplets tracking solved implicitly by means of CGSTAB or SIP methods, a modified iterative Messinger model using an improved water runback scheme for ice thickness calculation and three...

The understanding of the flow structures and the particle transport/deposition across the human bronchial system remains a challenge to achieve because of the complexity of the geometry of human lungs. This work relies a strong collaboration between physicians, medical imaging researchers, fluid mechanics researcher and CFD researchers. Four config...