Large Eddy Simulation Computations Research Articles

Turbulent jet simulation using high-order DG methods for aeroacoustic analysis

This work deals with the application of a high-order discontinuous Galerkin (DG) method to predict the noise generated by a subsonic free jet at high Reynolds number ReD=106, based on the nozzle diameter. The large-eddy simulation (LES) technique is used to compute the turbulent flow dynamics and acoustics in the near field. The estimation of the far-field noise is made by means of the Ffowcs Williams and Hawkings surface integral formulation. A fourth-order DG simulation of this jet configuration is presented in this paper. The DG simulation is based on the Smagorinsky model and the computational grid employed is fully tetrahedral. This DG simulation is compared to an LES computation performed in previous work by means of a second-order finite-volume (FV) solver using a similar type of grid and SGS model. The results from the DG and FV computations are also compared to the available experimental data. It appears from this study that the DG computation is able to resolve higher-frequency components close to the nozzle exit, which is related to the better match found with the experimental data in the far field.

Large eddy simulation of airfoil self-noise using OpenFOAM

PurposeThe purpose of this paper is to investigate airfoil self-noise generation and propagation by using a hybrid method based on the large-eddy simulation (LES) approach and Curle’s acoustic analogy as implemented in OpenFOAM.Design/methodology/approachLarge-eddy simulation of near-field flow over a NACA6512-63 airfoil at zero angle of attack with a boundary layer trip at Rec = 1.9 × 105 has been carried out using the OpenFOAM® computational fluid dynamics (CFD) code. Calculated flow results are compared with published experimental data. The LES includes the wind tunnel installation effects by using appropriate inflow boundary conditions obtained from a RANS κ – ω SST model computation of the whole wind tunnel domain. Far-field noise prediction was achieved by an integral method based on Curle’s acoustic analogy. The predicted sound pressure levels are validated against the experimental data at various frequency ranges.FindingsThe numerical results presented in this paper show that the flow features around a NACA6512-63 airfoil have been correctly captured in OpenFOAM LES calculations. The mean surface pressure distributions and the local pressure peaks for the step trip setup agree very well with the experimental measurements. Aeroacoustic prediction using Curle’s analogy shows an overall agreement with the experimental data. The sound pressure level-frequency spectral analysis produces very similar data at low to medium frequency, whereas the experimentally observed levels are slightly over predicted at a higher frequency range.Practical implicationsThis study has achieved and evaluated an alternative aeroacoustic simulation method based on the combination of LES with a simple Smagorinsky SGS model and Curle’s analogy, as implemented in the OpenFOAM CFD code. The unsteady velocity/pressure source data produced can be used for any simpler analytically based far-field noise prediction scheme.Originality/valueA complete integration of the LES and Curle’s acoustic analogy for aeroacoustic simulations has been achieved in OpenFOAM. The capability and accuracy of the hybrid method are fully evaluated for high-camber airfoil self-noise predictions. Wind tunnel installation effects have been incorporated properly into the LES.

Assessing the relationship between movement and airflow in the upper airway using computational fluid dynamics with motion determined from magnetic resonance imaging

BackgroundComputational fluid dynamics simulations of respiratory airflow in the upper airway reveal clinically relevant information, including sites of local resistance, inhaled particle deposition, and the effect of pathological constrictions. Unlike previous simulations, which have been performed on rigid anatomical models from static medical imaging, this work utilises ciné imaging during respiration to create dynamic models and more closely represent airway physiology. MethodsAirway movement maps were obtained from non-rigid image registration of fast-cine MRI and applied to high-spatial-resolution airway surface models. Breathing flowrates were recorded simultaneously with imaging. These data formed the boundary conditions for large eddy simulation computations of the airflow from exterior mask to bronchi. Simulations with rigid geometries were performed to demonstrate the resulting airflow differences between airflow simulations in rigid and dynamic airways. FindingsIn the analysed rapid breathing manoeuvre, incorporating airway movement significantly changed the findings of the CFD simulations. Peak resistance increased by 19.8% and occurred earlier in the breath. Overall pressure loss decreased by 19.2%, and the proportion of flow in the mouth increased by 13.0%.Airway wall motion was out-of-phase with the air pressure force, demonstrating the presence of neuromuscular motion. In total, the anatomy did 25.2% more work on the air than vice versa. InterpretationsRealistic movement of the airway is incorporated into CFD simulations of airflow in the upper airway for the first time. This motion is vital to producing clinically relevant computational models of respiratory airflow and will allow novel analysis of dynamic conditions, such as sleep apnoea.

Dynamic large eddy simulation: Stability via realizability

The concept of dynamic large eddy simulation (LES) is highly attractive: such methods can dynamically adjust to changing flow conditions, which is known to be highly beneficial. For example, this avoids the use of empirical, case dependent approximations (like damping functions). Ideally, dynamic LES should be local in physical space (without involving artificial clipping parameters), and it should be stable for a wide range of simulation time steps, Reynolds numbers, and numerical schemes. These properties are not trivial, but dynamic LES suffers from such problems over decades. We address these questions by performing dynamic LES of periodic hill flow including separation at a high Reynolds number Re = 37 000. For the case considered, the main result of our studies is that it is possible to design LES that has the desired properties. It requires physical consistency: a PDF-realizable and stress-realizable LES model, which requires the inclusion of the turbulent kinetic energy in the LES calculation. LES models that do not honor such physical consistency can become unstable. We do not find support for the previous assumption that long-term correlations of negative dynamic model parameters are responsible for instability. Instead, we concluded that instability is caused by the stable spatial organization of significant unphysical states, which are represented by wall-type gradient streaks of the standard deviation of the dynamic model parameter. The applicability of our realizability stabilization to other dynamic models (including the dynamic Smagorinsky model) is discussed.

Cholesky decomposition–based generation of artificial inflow turbulence including scalar fluctuation

This paper proposes a new method for generating turbulent fluctuations in wind velocity and scalars, such as temperature and contaminant concentration, based on a Cholesky decomposition of the time-averaged turbulent flux tensors of the momentum and the scalar for inflow boundary condition of large-eddy simulation (LES). The artificial turbulent fluctuations generated by this method satisfy not only the prescribed profiles for the turbulent fluxes of the momentum and the scalar but also the prescribed spatial and time correlations. Based on an existing method that is able to impose the spatial and time correlations using digital filters, random two-dimensional data are filtered to generate a set of two-dimensional data with the prescribed spatial correlation. Then, these data are combined with those from the previous time step by using two weighting factors based on an exponential function. The method was validated by applying generated inflow turbulence to an LES computation of contaminant dispersion in a half-channel flow.

Large-Eddy Simulation of a hydrogen enriched methane/air meso-scale combustor

A quasi–cubic meso-scale air/methane whirl flow combustion chamber, with no moving parts, is analyzed by means of high-fidelity Large-Eddy Simulations (LES). In order to consider partially premixed flames and differential diffusion process into the combustor, 3D LES computations include semi-detailed chemical kinetics mechanism and complex transport. They show that the reacting flow structure, flame topology and global efficiency are in line with previous experimental and less detailed numerical modeling. Combustion is stabilized by a Central Recirculation Zone (CRZ) and mainly takes place in premixed lean regime. Wall heat losses are also estimated and incomplete combustion zones are identified. Performances improvement was tested with hydrogen addition to fuel mixture. A small amount of hydrogen shows a global efficiency rise while keeping the whirl flow topology. The addition of a large amount of hydrogen implies a change in flame topology leading to a less complete combustion and pollutant formation. These results are in agreement with experimental data.

Large eddy simulation of methane diffusion jet flame with representation of chemical kinetics using artificial neural network

Chemical kinetics modeling within the numerical simulations of turbulent reactive flows is a critical issue. In this study, first a large eddy simulation of a non-premixed planar methane jet flame with artificial neural network -based chemical kinetics is performed. To consider the effects of turbulence on the evolution of the thermo-chemical state space, the artificial neural network training patterns are obtained by solving the unsteady reaction-diffusion equations of linear eddy mixing sub-grid combustion model. The optimization procedure for selecting the optimum neural network architecture is discussed in detail. A flow field analysis and a comparison between a non-reactive jet with the same velocity boundary conditions with the flame jet are performed. It is shown that the non-reactive jet is more turbulent and vortical structures of the non-reactive jet occur closer to the jet exit compared to the flame jet. Second, in a first attempt to quantify the influence of different chemical kinetics methods, large eddy simulation computations are performed with other methods used to represent the chemical kinetics such as direct integration and look-up table. A comparative study is performed between the averaged, instantaneous and fluctuation profiles of the scalar field and flame structures obtained by each method. Although all large eddy simulation results are very close to each other, the main discrepancy is observed for CO mass fractions obtained by artificial neural network and look-up table-based chemical kinetics simulations. It is also shown that the averaged scalar field and the conditional averaged values of the flame are overestimated by look-up table based chemical kinetics large eddy simulation computations. Moreover, the potential savings of artificial neural network in computational costs in comparison with other chemistry approaches are illustrated.

Numerical simulation and analysis of fluid flow hydrodynamics through a structured array of circular cylinders forming porous medium

Numerical analysis of the mechanisms that govern the flow in a porous region is crucial for modeling porous media flows. This study describes an adapted and efficient turbulence modeling technique for this category of porous media flows. The main objective of the present study is to provide a detailed pore scale description of fluid flow and to analyze the formation of coherent structures in the wake region close to the solid wall subject to the effects of fine-scale turbulence. The computations were performed in a three-dimensional representative elementary volume (REV) of a porous matrix, which comprised a periodic array of circular cylinders. Two flow-modeling strategies were employed: the steady Reynolds averaged Navier–Stokes (RANS) and transient large eddy simulation (LES) approaches. In the RANS modeling framework, both standard k–ε and low Re k–ε turbulence models were used. The porosity (ϕ) of the porous REV and Reynolds number (ReD) varied from 0.3 to 0.8 and 10 to 40,000, respectively. We investigated the effects of porosity and ReD on the pore scale velocity distribution, overall macroscopic pressure gradient, and turbulent dynamics, and performed comparisons using RANS and LES calculations within the porous REV. The Darcy parameter (i.e., medium permeability, K) was computed and a correlation was determined between the medium porosity and permeability. The macroscopic pressure gradients in the three-dimensional REV were also compared with the Kozeny–Carman and Darcy–Forchheimer law.

LES/PDF modeling of autoignition in a lifted turbulent flame: Analysis of flame sensitivity to differential diffusion and scalar mixing time-scale

The stabilization of lifted flames involves a complex competition between small-scale mixing and propagation of flame kernels at the base of the flame. Here, the effect of species diffusivity on this stabilization process is explored. For this purpose, a large-eddy simulation (LES)/probability density function (PDF) methodology accounting for differential diffusion is developed. A dynamic model for scalar mixing time-scale is formulated to accurately describe the turbulence-driven mixing of scalars at the small-scales. Autoignition-stabilized H2/N2 lifted turbulent flames in a vitiated coflow burner are chosen as test cases. Detailed chemical kinetics is used along with in situ adaptive tabulation (ISAT) to accelerate the computations. Four configuration test cases are considered: neglecting differential diffusion (Cases 1 and 2), considering differential diffusion (Case 3) and considering differential diffusion but neglecting molecular transport of H and H2 (Case 4). A dynamic model for scalar mixing time-scale appearing in the mixing model is used in Cases 2, 3 and 4, which removes the need to specify the value of model constant. It is found that the lifted flames are very sensitive to differential diffusion. The predictions of major species mass fractions, temperatures and lift-off heights are in good agreement with the experimental data. Further, such agreement could be achieved without changing any boundary conditions. In particular, increased diffusion of species upstream allows ignition kernels to survive turbulent dissipation, causing stabilization to occur upstream. H2 and H are identified as two critical species that play a dominant role in the differential diffusion effect. The model is also able to capture the change in lift-off height with change in coflow temperature. The results show that even in turbulent flames, stabilization of the flame zone can be sensitive to molecular diffusion. In LES computations where a significant part of this diffusion effect is resolved, the use of the enhanced LES/PDF/ISAT approach is seen as a promising approach for capturing the lift-off physics accurately.

Conditional Source-term Estimation using dynamic ensemble selection and parallel iterative solution

A modified version of the Least-Square QR-factorisation (LSQR) algorithm has been implemented in conjunction with Conditional Source-term Estimation (CSE) for lean, turbulent premixed methane–air combustion via Large Eddy Simulation (LES). The iterative solver can reduce computational times by an order of magnitude during the inversion phase of CSE in comparison with the conventional LU-decomposition method. The advantages of iterative and parallel iterative solvers become more prominent as the size of the system increases. The ensemble selection procedure for computing averages within localised regions of the simulation domain has also been updated to a dynamic routine. This allows for more flexible and efficient allocation of computational resources along with reduced input from the user, especially for complex geometries. Preliminary LES calculations have shown that the implementation of an iterative solver and a dynamic ensemble selection algorithm will reduce computational times significantly with negligible error contribution for one-condition CSE, which is applicable to purely premixed or non-premixed turbulent combustion problems. In addition, these algorithms provide the foundation for exceptional computational cost savings for the inversion in two-condition CSE, or Doubly Conditional Source-term Estimation (DCSE), which has shown promise for predicting partially-premixed combustion. Parallel computation of the inverse solution is particularly beneficial to DCSE as the computational cost of the inversion process is considerably larger than in one-condition CSE.

Turbulent boundary layers along straight and curved long thin circular cylinders at low angles-of-incidence

Long thin circular cylinders commonly serve as towed sonar tracking devices, where the radius-of-curvature along the longitudinal axis is quite low [ρr = O(10−4)]. Because no understanding presently exists about the direct impact of longitudinal curvature on the turbulent statistics, the long cylinder is simply viewed as a chain of straight segments at various (increasing then decreasing) small inclinations to the freestream direction. Realistically, even our statistical evidence along straight thin cylinders at low incidence angles is inadequate to build solid evidence towards forming reliable empirical models. In the present study, we address these shortcomings by executing Large-Eddy Simulations (LESs) of straight and longitudinally curved thin cylinders at low to moderate turbulent radius-based Reynolds numbers (500 ≤ Rea ≤ 3500) and small angles-of-incidence (α = 0° → 9°). Coupled with the previous experimental measurements and numerical results, the new expanded database (311 ≤ Rea ≤ 56 500) delivered sufficient means to propose power-law expressions for the longitudinal evolution of the skin friction, normal drag, and turbulent boundary layer (TBL) length scales. Surprisingly, the LES computations of the curved cylinders at analogous geometric and kinematic conditions as the straight cylinder showed similar character in terms of the longitudinal skin friction. Beyond incidence 1°-3° (upper end corresponds to the highest simulated Rea), the skin friction was directly proportional to the yaw angle and monotonically shifted downward with higher Rea. Conversely, the flow structure, normal drag, TBL length scales, Reynolds stresses, and the separation state of the transverse shear layers towards regular vortex shedding for the curved cylinder were highly dissimilar than the straight one at equivalent incidence angles.

Impact of domain size and statistical errors in simulations of homogeneous decaying turbulence and the Richtmyer-Meshkov instability

Both experiments and computations are naturally constrained by boundary conditions. In fundamental problems such as homogeneous decaying turbulence (HDT) or shock-induced mixing layers, a size constraint naturally limits the growth of the large scales in the problem, modifying the physics observed. This paper explores through Large Eddy Simulation (LES) the integral properties using computations from 1283 to 10243 for HDT and 1283 to 5123 for the Richtmyer-Meshkov instability (RMI). Kinetic energy decay rates in both cases are shown to be relatively insensitive to the domain size until the spectral peak is at the first wave number. The integral length is significantly more sensitive, showing substantial discrepancies once it is greater than 10% of the domain size. However, the key error is shown to be due to a lack of statistical averaging once the integral length is greater than 5% of the box size, thus appearing earlier than the length scale saturation. This highlights that a single computation at modest grid resolution (≤2563) may not reproduce the correct physics and that at this resolution, numericists need to embrace the practice of using multiple independent realisations to reduce the statistical error, as is the norm for the experimentalist. Finally, an update on the physics of HDT and RMI as predicted through LES computations is presented.

Large Eddy Simulation of Turbulent Slot Jet Impingement Heat Transfer at Small Nozzle-to-Plate Spacing

We present fluid flow and heat transfer of a slot jet impingement heat transfer at a small value of the nozzle-to-plate spacing at which a secondary peak in the Nusselt number is observed. Large eddy simulation has been performed with a finite-volume-based computational fluid dynamics code and using a dynamic Smagorinsky model. The optimum domain size and grid for large eddy simulation (LES) have been produced based on LES computations on a coarse mesh and Reynolds-averaged Navier–Stokes-based computations. Two inflow conditions, namely, using the vortex method and no perturbations, were compared. The present LES results, using the vortex method, capture the secondary peak in the Nusselt number better as compared to the case with no perturbations. Results show that mean velocity profile in the stagnation region deviates from the standard law of the wall. Further, large-scale vortical structures were observed near the location of the secondary Nusselt number peak. Increases in both the streamwise and wall normal turbulence fluctuations are observed near the secondary peak in the Nusselt number. The secondary peak in Nusselt number is found to be associated with the combined effect of flow acceleration and an increase in the turbulence kinetic energy.

Experimental and numerical study of a generic conventional submarine at 10° yaw

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 the DSTO Low-Speed Wind Tunnel, with data collected using pressure probes, Particle Image Velocimetry (PIV) and flow visualization using wool-tuft streamers. Computational studies using LES on unstructured meshes of up to 340 million cells provide detailed surface and off-body flow field data, complementing the experimental investigations and providing the opportunity for reciprocal validation of experiments and computations. Surface-flow patterns for the DSTO generic submarine model at 10° yaw and a freestream Reynolds (Re) number, based on wind tunnel speed and hull length, of Re=4.5×106 were obtained. The cross-stream velocity for the DSTO generic submarine model at 10° yaw and Re=2.7×106 was measured using PIV. The in-plane velocity was measured at three streamwise locations corresponding to 65%, 84% and 98% of the submarine model length. LES computations were performed using an incompressible LES flow solver developed using OpenFOAM and unstructured tetrahedral grids generated utilizing a patch-based approach to facilitate high near-wall resolutions and arbitrary refinement for appendage wakes.

Numerical Investigation of Flow Control for a Flat-Window Cylindrical Turret

This work presents multiple high-fidelity large-eddy simulations of flow over a cylindrical turret with a flat window oriented at two angles, 90 and 100 deg. For the 100 deg case, additional computations were performed to investigate the effectiveness of multiple types of flow control including rows of short pins, tall pins, and steady blowing wall jets inserted upstream of the turret as well as a steady suction slot at the leading edge of the flat window. The large-eddy simulation computations were obtained using a well-validated high-order Navier–Stokes flow solver employing a sixth-order compact spatial discretization in conjunction with an eighth-order low-pass spatial filter. Overall, large-eddy simulation solutions compared favorably to experimental time mean and fluctuating velocity profiles as well as the general flow structure at both angles. Additionally, valuable insight was obtained on how rows of pins, blowing jets, and steady slot suction control flow separation. Slot suction at the upwind aperture lip was determined to be more effective than rows of pins and blowing jets in controlling flow separation, which is critical in reducing aero-optical aberrations. Steady slot suction was capable of eliminating massive separation at a larger look angle of 120 deg.

CFD modeling of homogenizer valve: A comparative study

Designing an efficient homogenizer valve requires an in-depth understanding of the flow structure in the valve region. Therefore, the choice of an appropriate strategy in the numerical simulation of homogenization and chemical process plays a significant role and determines the accuracy of results which returns an improved design criterion. The performance of two computational fluid dynamics (CFD) strategies in the simulation of a homogenizer valve is assessed in this study; namely, the large eddy simulation (LES) and hybrid LES-RANS methods. For LES calculations, two sub-grid scale (SGS) models are considered: (a) RAST one-equation model (OEM) (b) dynamic Smagorinsky model (DSM) while the SST-SAS and delayed detached eddy simulation (DDES) methods are the variants of a hybrid-type RANS-LES approach. The predictions of these models are compared with the experimental data available in the literature. The comparisons show that an LES can reproduce accurate information in terms of main parameters such as the mean velocity and turbulent kinetic energy that are important in designing the homogenization process. However, the SST-SAS predictions are not as accurate as the DDES and LES ones, especially downstream of the gap in reproducing the mean velocity and turbulent fluctuations.

Assessment of dynamic closure for premixed combustion large eddy simulation

Turbulent piloted Bunsen flames of stoichiometric methane–air mixtures are computed using the large eddy simulation (LES) paradigm involving an algebraic closure for the filtered reaction rate. This closure involves the filtered scalar dissipation rate of a reaction progress variable. The model for this dissipation rate involves a parameter βc representing the flame front curvature effects induced by turbulence, chemical reactions, molecular dissipation, and their interactions at the sub-grid level, suggesting that this parameter may vary with filter width or be a scale-dependent. Thus, it would be ideal to evaluate this parameter dynamically by LES. A procedure for this evaluation is discussed and assessed using direct numerical simulation (DNS) data and LES calculations. The probability density functions of βc obtained from the DNS and LES calculations are very similar when the turbulent Reynolds number is sufficiently large and when the filter width normalised by the laminar flame thermal thickness is larger than unity. Results obtained using a constant (static) value for this parameter are also used for comparative evaluation. Detailed discussion presented in this paper suggests that the dynamic procedure works well and physical insights and reasonings are provided to explain the observed behaviour.

Numerical laser beam propagation using large eddy simulation of a jet engine flow field

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 scale turbulent eddies. The refractive index data from the LES calculations were integrated along the propagation path to produce time resolved phase screens for optical beam propagation. The phase screens were used to calculate laser beam parameters including beam wander and power-in-bucket (PIB). Numerical beam propagation resulted in a root-mean-square beam wander of 200 μrad for the small turbojet engine studied. The PIB was calculated for beams with 80 μrad and 2 mrad divergence having equal beam diameter when passing through the plume. For the beam with low divergence, the average PIB was reduced from 0.23 to 0.040, while the beam with wider divergence showed no significant reduction. In both cases, the plume introduced significant temporal variation of the instantaneous PIB. The beam wander is not affected by the divergence, but only depends on beam size.

Large Eddy Simulations of convergent–divergent channel flows at moderate Reynolds numbers

The paper is focused on the study of fully turbulent channel flows, using Large Eddy Simulations (LES), in order to address the effects of adverse pressure gradient regions. Analyses of the effects of streak instabilities, which have been shown to be relevant in such regions, are extended to moderate Reynolds numbers. The work considers two different channel geometries in order to further separate influences from wall curvature, flow separation and adverse pressure gradients. Turbulent kinetic energy and Reynolds stress budgets are investigated at separation and re-attachment points. The numerical approach used in the present work is based on the incompressible Navier–Stokes equations, which are solved by a pseudo-spectral methodology for structured grids. Wall-resolved LES calculations are performed using the WALE subgrid scale model. The study shows that the streak instability mechanism persists at higher Reynolds numbers with and without wall curvature in the adverse pressure gradient regions. Moreover, the observed effects are also present regardless of the existence of flow separation regions. Finally, the study of turbulent kinetic energy budgets indicates that, independently of the flow condition, there are well-defined patterns for such turbulent properties at separation and re-attachment points.

Fuel flexibility, stability and emissions in premixed hydrogen-rich gas turbine combustion: Technology, fundamentals, and numerical simulations

Abstract The objective of this paper is to review the progress made in understanding the effects of fuel composition on premixed gas turbine combustion, with a special emphasis on system stability and emissions, for hydrogen-rich synthetic gas (syngas) mixtures. This is driven by the rising interest in the use of hydrogen blends and syngas in combined cycle power plants, as an alternative to standard natural gas. Typical applications where such mixtures are used include the recycling of hydrogen by-product from industry as well as promising pre-combustion carbon capture methods like fuel reforming or gasification integrated with gas turbine combined cycle plants. Syngas is mainly a mixture of H2, CO and CH4; its composition can vary due to fluctuations in the process’s conditions but can also dramatically change if the feedstock is modified like coal or biomass grades in gasification. Due to the substantially different chemical, transport and thermal properties that distinguish the syngas components, especially H2, when compared with conventional hydrocarbon fuels, these non-standard fuels pose several challenges in premixed combustion. These challenges are reviewed in this paper along with the combustion fundamentals of these fuels. A survey of available technologies able to handle syngas and hydrogen-rich fuel in general is provided reflecting the difficulties encountered while using these fuels in real large scale commercial applications. We find that a limited number of options exist today for fully premixed combustion, but promising designs are under development. Finally, the ever growing use of numerical simulation to cost-effectively study full scale combustion systems—with Large Eddy Simulations (LES) being at the forefront as a compromise between accuracy and computational cost—justifies the simultaneous review of the different numerical attempts to simulate hydrogen-containing fuel mixtures and syngas in premixed combustion. Challenges specific to performing LES calculations for these reacting flows are highlighted. We find that, while the literature on premixed LES methane combustion is abundant, LES of premixed syngas and hydrogen-rich fuels combustion is comparatively scarce. Only few attempts were made so far showing the need for more research effort in this area to help tackle the challenges presented by these fuels.