Christer Fureby

• Swedish Defence Research Agency

We live in a turbulent world observed through coarse grained lenses. Coarse graining (CG), however, is not only a limit but also a need imposed by the enormous amount of data produced by modern simulations. Target audiences for our survey are graduate students, basic research scientists, and professionals involved in the design and analysis of comp...

We live in a turbulent world observed through coarse grained lenses. Coarse graining (CG), however, is not only a limit but also a need imposed by the enormous amount of data produced by modern simulations. Target audiences for our survey are graduate students, basic research scientists, and professionals involved in the design and analysis of comp...

In this study, we report on reactive large-eddy simulations (LESs) of flow and combustion in the U.S. Air Force Research Laboratory Research Cell 19 cavity-based scramjet combustor. This case involves the combustion of ethylene that is injected into a cavity. It has previously been studied experimentally with multiple techniques, including particle...

Schlieren imaging has been established as a reliable optical measurement technique for flame visualizations and retrieval of laminar burning velocity information. However, it is off limited capability and adaptability due to the optical configuration of a conventional schlieren setup. In this regard, background oriented schlieren (BOS) provides a...

Sustainability of future aviation platforms is heavily dependent on the lower emission capabilities of aeroengines which can be addressed by means of utilizing jet fuels of biological origin. Thus, an extensive experimental and numerical investigation campaign utilizing the Triple Annular Research Swirler (TARS) burner is started to understand the...

Additive manufacturing creates surfaces with random roughness, impacting heat transfer and pressure loss differently than traditional sand–grain roughness. Further research is needed to understand these effects. We conducted high-fidelity heat transfer simulations over three-dimensional additive manufactured surfaces with varying roughness heights...

In this paper, the performance of a helicopter engine's combustion chamber burning sustainable aviation fuels is studied using both experimental and numerical approaches. Experiments were conducted at the Swedish Maritime Agency base in Kristanstad, Sweden, examining the emission profiles of the main exhaust species from one of the two Pratt & Whit...

Additive manufacturing creates surfaces with random roughness, impacting heat transfer and pressure loss differently than traditional sand-grain roughness. We conducted high-fidelity heat transfer simulations over three-dimensional additive manufactured surfaces with varying roughness heights and skewness. Based on an additive manufactured Inconel...

Polymer solutions in the dilute regime play a significant role in industrial applications. Due to the intricate rheological properties of these highly viscoelastic fluids, especially in complex flow geometries, a thorough numerical analysis of their flow dynamics is imperative. In this research, we present a numerical investigation of purely elasti...

Wall-bounded turbulence is relevant for many engineering and natural science applications, yet there are still aspects of its underlying physics that are not fully understood, particularly at high Reynolds numbers. In this study, we investigate fully developed turbulent pipe flows at moderate-to-high friction velocity Reynolds numbers (361≤Reτ≤2000...

The degraded resolution and sensitivity characteristics of BOS can be recovered by means of utilizing an optical flow based image processing scheme. However, the background patterns conventionally employed in BOS setups suit the needs of the cross-correlation approach, whereas optical flow is based on a completely different mathematical background....

To study the impact of additively manufactured (AM) roughness on fluid flow and heat transfer, we performed a series of high-fidelity large-eddy simulations on turbulent heat transfer over a three-dimensional AM rough surface with varying bulk Reynolds number and average roughness height values. We considered rough surfaces created using AM techniq...

With growing interest in sustainable civil supersonic and hypersonic aviation, there is a need to model the combustion of alternative, sustainable jet fuels. This work presents numerical simulations of several related phenomena, including laminar flames, ignition, and spray flames. Two conventional jet fuels, Jet A and JP-5, and two alternative jet...

Turbulent spray combustion in a generic kerosene-fueled single-cup combustor at typical idle and cruise conditions of an aeroengine are studied with Large Eddy Simulations (LES) using Lagrangian spray and finite-rate chemistry combustion modeling. Three reaction mechanisms of varying complexity are used to model the combustion chemistry. The choice...

The degraded resolution and sensitivity characteristics of BOS can be recovered by means of utilizing an optical flow based image processing scheme for the displacement detection stage. However, the background patterns conventionally employed in BOS setups suit the needs of the cross-correlation approach, whereas optical flow is associated with a c...

The need for comparative studies between experimental and numerical results exists due to the long lasting necessity for verification and validation. Accordingly, background oriented schlieren (BOS) provides a unique opportunity to perform non intrusive quantification of density varying flows by means of an inexpensive and simple setup. As the opti...

In the last decade, with the growing demand for efficient and more sustainable products that reduce our CO2 footprint, progresses in Additive Manufacturing (AM) have paved the way for optimized heat exchangers, whose disruptive design will heavily depend on predictive numerical simulations. Typical AM rough surfaces show limited resemblance to the...

In the last decade, progresses in additive manufacturing (AM) have paved the way for optimized heat exchangers, whose disruptive design will depend on predictive numerical simulations. Typical AM rough surfaces show limited resemblance to the artificially constructed rough surfaces that have been the basis of most prior fundamental research on turb...

Aviation currently contributes about 3% of the world’s CO2 emissions, 5% of the global warming, and 35% of the trade. Reducing the emissions and the global warming from aviation is thus essential. Many approaches to achieve this goal are underway, including H2, fuel cells, and batteries, but also by replacing the fossil jet fuel with sustainable je...

Optical flow provides an opportunity to elevate the resolution and sensitivity of deflection sensing in background-oriented schlieren (BOS). Despite extensive relevant literature within the field of computer vision, there is a lack of proper quantification of its abilities and limitations with regard to the state-of-the-art BOS experiments. Thus, t...

The aviation sector is facing a massive change in terms of replacing the currently used fossil jet fuels (Jet A, JP5, etc.) with non-fossil jet fuels from sustainable feedstocks. This involves several challenges and, among them, we have the fundamental issue of current jet engines being developed for the existing fossil jet fuels. To facilitate suc...

Large Eddy Simulation (LES) has rapidly developed into a powerful computational methodology for fluid dynamic studies, between Reynolds-Averaged Navier–Stokes (RANS) and Direct Numerical Simulation (DNS) in both accuracy and cost. High-speed combustion applications, such as ramjets, scramjets, dual-mode ramjets, and rotating detonation engines, are...

Despite the high relevance of wall-bounded turbulence for engineering and natural science applications, many aspects of the underlying physics are still unclear. In particular, at high Re close to many real-life scenarios, the true nature of the flow is partially masked by the inability of numerical simulations to resolve all turbulent scales adequ...

Optical flow provides an opportunity to elevate the resolution and sensitivity of deflection sensing in background oriented schlieren (BOS). Despite extensive relevant literature within the field of computer vision, with regards to BOS, there is a lack of proper quantification of its abilities and limitations. Thus, this study performs a comparativ...

The effect of a rotating gliding arc (RGA) plasma discharge on the flame in a downscaled Siemens Energy dry low emission, SGT-750, burner was experimentally investigated under atmospheric combustion conditions. The central pilot section of the burner, named RPL (rich-pilot-lean), was redesigned with an integrated high-voltage electrode to generate...

Laminar burning velocity of lean methane/air flames exposed to pulsed microwave irradiation is determined experimentally as part of an effort to accurately quantify the enhancement resulting from exposure of the flame to pulsed microwaves. The experimental setup consists of a heat flux burner mounted in a microwave cavity, where the microwave has a...

Development and validation of a new reduced dimethyl ether-air (DME) reaction mechanism is presented. The mechanism was developed using a modular approach that has previously been applied to several alkane and alkene fuels, and the present work pioneers the use of the modular methodology, with its underlying H/C1/O base mechanism, on an oxygenated...

Explore a thorough and up to date overview of the current knowledge, developments and outstanding challenges in turbulent combustion and application. The balance among various renewable and combustion technologies are surveyed, and numerical and experimental tools are discussed along with recent advances. Covers combustion of gaseous, liquid and so...

As eluded in previous studies, with special reference to those carried out in the European framework, some innovative high-speed aircraft configurations have now the potential to assure an economically viable high-speed aircraft fleet. They make use of unexploited flight routes in the stratosphere, offering a solution to the presently congested fli...

Methane is an important fuel for gas turbine and gas engine combustion, and the most common fuel in fundamental combustion studies. As Computational Fluid Dynamics (CFD) modeling of combustion becomes increasingly important, so do chemical kinetic mechanisms for methane combustion. Kinetic mechanisms of different complexity exist, and the aim of th...

The effect of a Rotating Gliding Arc (RGA) plasma discharge on the flame in a scaled Siemens Dry Low Emission (DLE), SGT-750, burner was experimentally investigated under atmospheric combustion conditions. The central pilot section of the burner, named RPL (rich pilot lean), was redesigned with an integrated high voltage electrode to generate an RG...

This paper addresses the main progresses and achievements of the H2020 STRATOFLY Project, funded by the European Commission, under the Horizon 2020 framework, specifically looking at the latest results in terms of environmental sustainabil-ity. In particular, starting from reporting the main environmental challenges posed by high-speed civil transp...

This paper addresses the main progresses and achievements of the H2020 STRATOFLY Project, funded by the European Commission, under the Horizon 2020 framework, specifically looking at the latest results in terms of environmental sustainabil-ity. In particular, starting from reporting the main environmental challenges posed by high-speed civil transp...

As eluded in previous studies, with special reference to those carried out in the European framework, some innovative high-speed aircraft configurations have now the potential to assure an economically viable high-speed aircraft fleet. They make use of unexploited flight routes in the stratosphere, offering a solution to the presently congested fli...

Development of a new reduced chemical kinetic reaction mechanism for kerosene-air combustion is presented. The new mechanism uses a modular based development technique and is a further development on previously presented kerosene-air mechanisms. The new mechanism consists of 30 species and 77 irreversible reactions and is developed to accurate repr...

Plasma assisted combustion is a very active research field due to the potential of using the technology to improve combustion efficiency and decrease pollutant emission by stabilizing lean burning flames. It has been shown in a number of studies that a small amount of electrical energy can be deposited in the flame by applying microwaves, resulting...

An a priori analysis of a DNS database of turbulent lean premixed methane flames is presented considering the relative effects of turbulence and LES filtering, along with a potential modelling approach for LES with finite-rate chemistry. The leading-order effect was found to be due to the filter operation; flame response to turbulence was a seconda...

Dual-mode ramjet/scramjet engines are considered a promising propulsion system for the next generation commercial high-speed transport flight vehicles. In this study we combine experimental measurements of high-speed (subsonic and supersonic) combustion at different operating conditions in the LAPCAT-II dual-mode ramjet/scramjet combustor with Larg...

Combustion instabilities are one of the major challenges in developing and operating propulsion and power generating gas-turbine engines. More specifically, techniques for managing the increasingly stringent emissions regulations and efficiency demands have often given rise to thermo-acoustic instabilities, particularly for annular combustors opera...

Design requirements for submarines regarding resis- tance, manoeuvrability, stability and stealth tighten with each new generation. Fully understanding the fluid dynamics of these vessels is key if spec- ifications are to be met. Extending earlier near- wall modelled LES studies of a full-scale, fully- appended Joubert generic conventional submarin...

An a priori analysis of a DNS database of turbulent lean premixed methane flames is presented considering the relative effects of turbulence and LES filtering, along with a potential modelling approach for LES with finite-rate chemistry. The leading-order effect was found to be due to the filter operation; flame response to turbulence was a seconda...

Ethylene is a fuel considered for high speed ram- and scramjet combustion applications, mainly because of the short ignition delay time resulting from its high reactivity. Further research and development on these combustion systems would benefit from simulations of Large Eddy (LES) type, which allow some chemical detail to accurately predict combu...

Large Eddy Simulations (LES) of a swirl-stabilized natural gas-air flame in a laboratory gas turbine combustor is performed using six different LES combustion models to provide a head-to-head comparative study. More specifically, six finite rate chemistry models, including the thickened flame model, the partially stirred reactor model, the approxim...

A review is presented of estimates for the grid resolution requirements for wall-resolved and wall-modeled large-eddy simulation, of flows with an important influence of turbulent boundary layers. The estimates are described within a classification scheme which is formulated based on the grid resolution relative to the length scales of the turbulen...

The increasing computational capacity in recent years has spurred the growing use of combustion Large Eddy Simulation (LES) for engineering applications. The modeling of the subgrid stress and flux terms is well-established in LES, whereas the modeling of the filtered reaction rate terms is under intense development. The significance of the reactio...

Irradiating a flame by microwave radiation is a Plasma Assisted Combustion (PAC) technology that can be used to modify the combustion chemical kinetics in order to im¬prove flame stability and to delay lean blow-out. One practical implication is that combustion en¬gines may be able to operate with leaner fuel mixtures and have an improved fuel flex...

Efficient and clean production of electrical energy and mechanical (shaft) energy for use in industrial and domestic applications, surface- and ground transportation and aero-propulsion is currently of significant general concern. Fossil fuels are mainly used for transportation and aero-propulsion, but also for power generation. Combustion of fossi...

This paper describes the current state of the art in large eddy simulation (LES) of engineering flows. As LES is used in a wide range of applications (aerodynamics, hydrodynamics, combustion, etc.) an attempt is made here to provide a compact but still comprehensive description of the method, and to give an overview of how LES is employed to study...

Detailed understanding of the physical processes occurring in the combustor of a scramjet engine is crucial for enabling this technology and is considered the most promising for hypersonic flight. Laboratory, ground testing, and flight-testing experiments, together with simulations, comprise the tools available to fill the current gap in scramjet c...

The development and validation of a new skeletal mechanism for kerosene combustion, suitable for reacting direct-, large-eddy and Reynolds averaged Navier Stokes Simulations, is presented. The mechanism consist of 65 irreversible reactions between 22 species, and build on a global fuel breakdown approach to produce a subset of C2 intermediates. A m...

A review is presented of estimates for the grid resolution requirements for near-wall resolved and near-wall modelled large-eddy simulation, of flows with an important influence of turbulent boundary layers. The estimates are described within a classification scheme which is formulated based on the grid resolution relative to the length scales of t...

The present study investigates the afterburning from an explosion of a spherical 2,4,6-Tri-Nitro-Toluene (TNT) charge containing aluminum particles at four different Heights of Burst (HoB), to demonstrate that numerical simulations can facilitate the evaluation of the performance of Enhanced Blast eXplosives (EBX). The simulations are conducted usi...

Irradiating a flame by microwave radiation is one of several plasma-assisted combustion (PAC) technologies that can be used to modify the combustion chemical kinetics in order to improve flame-stability and to delay lean blow-out. One practical implication is that engines may be able to operate with leaner fuel mixtures and have an improved fuel fl...

Grid requirements for LES of wall-bounded flows are considered. The setting is a zero pressure gradient turbulent boundary layer on a flat plate, but the results are intended to be of use generally for the simulation of flows with an important influence of turbulent boundary layers. The basis for the grid estimates are expressions for the thickness...

The flow around the KVLCC2 model tanker hull at 0°, 12° and 30° drift is investigated using classical Reynolds Averaged Navier–Stokes (RANS) models from two different proprietary codes, hybrid RANS-LES models from one of these proprietary codes, and Large Eddy Simulation (LES) models from a third, semi-proprietary code. Understanding the three-dime...

An experimental setup for microwave stimulation of a turbulent flame is presented. A low-swirl flame is being exposed to continuous microwave irradiation inside an aluminum cavity. The cavity is designed with inlets for laser beams and a viewport for optical access. The aluminum cavity is operated as a resonator where the microwave mode pattern is...

This investigation discusses the flow physics of the fully appended DSTO generic submarine model at both straight ahead conditions and during a 10° side-slip. Reynolds Averaged Navier Stokes (RANS) and Large Eddy Simulation (LES) computations have been performed and are compared with model-scale experiments. The experiments have been carried out in...

In this investigation the physics of the reacting swirling flow of a commercial industrial gas turbine burner (SGT-100) was researched using combustion Large Eddy Simulation (LES) and experiments. In the experimental studies the flow field, temperature and major species concentrations were measured using Particle Image Velocimetry (PIV), OH Planar...

In certain directed infrared countermeasure (DIRCM) situations, the laser beam path may have to pass close to the engine exhaust plume of the aircraft and models of plume turbulence are needed for DIRCM performance simulations. The jet engine plume was modeled using large eddy simulation (LES), providing time resolved information about the large sc...

Small-scale turbulent flow dynamics is traditionally viewed as universal and as enslaved to that of larger scales. In coarse grained simulation (CGS), large energy-containing structures are resolved, smaller structures are spatially filtered out, and unresolved subgrid scale (SGS) effects are modeled. Coarse Grained Simulation and Turbulent Mixing...

Laser beam propagation in severe environments such as a jet engine exhaust may influence performance of Airborne Optical Systems such as Missile Early Warning Systems or Directed Infrared Countermeasures. Laser beam propagation in close vicinity of the engine plume causes performance degradation due to beam wander, and beam broadening effects. In t...

In plasma-assisted combustion, electric energy is added to the flame where the electric energy will be transferred to kinetic energy of the free electrons that, in turn, will modify the combustion chemical kinetics. In order to increase the understanding of this complex process, the influence of one of the products of the altered chemical kinetics,...

Achieving sufficiently high combustion efficiency and stability in supersonic combustion is extremely challenging and highly dependent on the fuel-injection and mixing strategies adopted. A viable approach to this is the strut injector, which by inducing flow recirculation, facilitates flame stabilization in the strut-wake. In this investigation we...

Experimental and flight data for hypersonic air-breathing engines are both difficult and extremely expensive to obtain, motivating the use of computational models to enhance the understanding of the complex physics involved. Here, a comprehensive numerical study has been carried out for the HyShot II scramjet combustor. This study makes use of Reyn...

We have investigated the possibilities of using Computational Fluid Dynamics (CFD) simulations to characterize the impact of refractive index fluctuations in a jet engine plume on Directed InfraRed CounterMeasure (DIRCM) system performance. The jet plume was modelled using both Reynolds-Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES)...

In this study, large eddy simulation (LES) has been used to examine supersonic flow, mixing, self-ignition and combustion in a model scramjet combustor and has been compared against the experimental data. The LES model is based on an unstructured finite-volume discretization, using monotonicity-preserving flux reconstruction of the filtered mass, m...

Transports of substances to or from Seveso classified facilities are always a dangerous link in today's industrial societies. Despite the risk of serious accidents, it is common that these transports use routes that pass through densely populated urban areas. We present a computational concept employing a multi-model simulation platform that allows...

In this work, large-eddy simulation is used to study the flow around a circular cylinder undergoing streamwise sinusoidal oscillations. This benchmark case is a first step toward studying engineering applications related to flow-induced vibrations. Both the flow physics, which correlate the flow development with the time varying loading of the cyli...

In this work, a novel model for Large Eddy Simulations (LES) of high Reynolds moderate Damköhler number turbulent flames is proposed. The development is motivated by the need for more accurate and versatile LES combustion models for engineering applications such as jet engines. The model is based on the finite rate chemistry approach in which the f...