Flow, Turbulence and Combustion最新文献

{"title":"Investigation of Hypersonic Boundary-Layer Transition on a Typical Re-Entry Vehicle: Insights into Spot-like, Non-Modal Breakdown Mechanisms","authors":"Dibya Kanti Golui,&nbsp;S. L. N. Desikan","doi":"10.1007/s10494-026-00751-1","DOIUrl":"10.1007/s10494-026-00751-1","url":null,"abstract":"<div>\u0000 \u0000 <p>The onset of boundary-layer transition on the windward side of a typical re-entry vehicle, fixed at its hypersonic trim angle of attack of 40⁰, has been experimentally investigated. The study is conducted in a combustion-driven shock tunnel, tailored at a stagnation enthalpy of 2.4 MJ/kg and a freestream Mach number of 8. Transition is characterized using time-resolved surface heat-flux measurements, which provide a sensitive indicator of laminar-turbulent breakdown in hypersonic flows. Experiments are performed over a wide range of unit Reynolds numbers from 1.48 × 10⁶ to 5.34 × 10⁶ m^− 1. At lower Reynolds numbers, the boundary layer exhibits laminar characteristics with asymptotic heat-flux trends. Conversely, at higher Reynolds numbers, intermittent and finite-duration disturbances consistent with turbulent-spot-like breakdown events appear in the transient heat flux traces. These are observed to convect, grow, and merge downstream, producing elevated heating with broadband temporal fluctuations characteristic of turbulence. Furthermore, with increasing Reynolds number, time-averaged heat flux levels rise at downstream stations and the onset of transition progressively shifts upstream, consistent with the Reynolds-number dependence of transitional flows. Finally, the hypothesis of concentrated breakdown, originally formulated for flat plates, is adapted to the present re-entry geometry to reconstruct the heat flux distribution within the transitional boundary layer, demonstrating that spot-based intermittency concepts can be meaningfully incorporated into transition interpretation for hypersonic re-entry configurations featuring mild favourable streamwise pressure gradients. This study thus provides new physical insight into hypersonic boundary-layer transition in non-canonical geometries of practical relevance by offering an experimentally grounded interpretation based on non-modal, stochastic mechanisms.</p>\u0000 </div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 4","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147727448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LES-ADM Accuracy Assessment via An Error-Landscape Approach","authors":"Lena Caban,&nbsp;Artur Tyliszczak,&nbsp;Bernard J. Geurts","doi":"10.1007/s10494-026-00750-2","DOIUrl":"10.1007/s10494-026-00750-2","url":null,"abstract":"<div><p>This paper investigates the accuracy and robustness of the approximate deconvolution method (ADM) in large eddy simulation (LES) using an error-landscape approach. Two canonical turbulence test cases—forced and decaying homogeneous isotropic turbulence (F-HIT / D-HIT)—are analyzed. We assess how user-defined parameters in ADM, including the filter type, its order (<span>(p=2-10)</span>), and the number of deconvolution iterations (<span>(N_textrm{ADM}=0-10)</span>), affect the predictive performance of the model. Finite and compact difference filters are employed for deconvolution. Along with the box and Gaussian filters, these are also used as an LES filter. The resulting errors associated with the use of ADM are compared with LES errors arising from the Smagorinsky model with a model constant in the range <span>(0 &lt; C_Sle0.2)</span> (20 levels), and a no-model approach. The LES results are validated against direct numerical simulation (DNS) data. For the F-HIT case, we focus on the accuracy of the prediction of time-averaged kinetic energy and skewness of the velocity components and their derivatives. In the case of the Smagorinsky model, accurate results are obtained for <span>(C_Sle0.1)</span>, while for ADM <span>(pge6)</span> and <span>(N_textrm{ADM}=2)</span> appear to be required. An exception is the prediction of the velocity-derivative skewness, which, in all cases, differs significantly from the DNS solution due to its strong reliance on small-scale flow features. The classical error-landscape approach is applied for the D-HIT configuration. By performing direct comparisons of key solution properties, this approach enables identifying the parameter range in which ADM attains optimal accuracy leading to results that are more accurate than can be obtained by applying the Smagorinsky model, as well as regions where ADM-based simulations may become unstable or exhibit accuracy levels inferior to the reference no-model case. The latter arises especially on coarse grids when <span>(N_textrm{ADM}geq 2)</span>, or when the LES filter does not sufficiently attenuate the solution at the grid cut-off frequency. From the perspective of simulation stability, the safer choice is to perform deconvolution with a high-order filter, preferably an implicit formulation, which also ensures considerable accuracy. The total analysis encompasses comparisons of over <span>(6000)</span> simulations. It provides valuable guidance for the effective use and future development of stable ADM-based modeling strategies. In this respect, an important finding is that increasing <span>(N_textrm{ADM})</span>, rather than improving deconvolution accuracy, may lead to instability reflecting the ill-posedness of recovering scales that are poorly represented on the chosen simulation grid.</p></div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 4","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of Triangle-shaped Protrusions Exposed to High-speed Flow in Rarefied Regime","authors":"Moslem Sabouri,&nbsp;Elyas Lekzian","doi":"10.1007/s10494-026-00741-3","DOIUrl":"10.1007/s10494-026-00741-3","url":null,"abstract":"<div>\u0000 \u0000 <p>This study examines the aerodynamic effects of 2D triangular protrusions on hypersonic flow within transitional regimes using the Direct Simulation Monte Carlo method. Three protrusion geometries-isosceles, backward, and forward-are analyzed. Results indicate that the forward geometry exhibits the highest in-domain pressure and temperature peaks, along with elevated surface pressure, heat transfer coefficients, and boundary layer thickness. The backward configuration shows greater sensitivity of peak temperature to protrusion surface temperature variations, while the forward case demonstrates higher pressure sensitivity. Across all configurations, maximum pressure (<span>(:{C}_{p,:max})</span>) and heat transfer (<span>(:{C}_{h,:max})</span>) coefficients occur on the windward surface, with (<span>(:{C}_{p,:max})</span>) increasing and (<span>(:{C}_{h,:max})</span>) decreasing with rising surface temperatures. For the protrusion height ratio <span>(:{h}_{p}/{h}_{s})</span> of 1.0, the isosceles configuration exhibits almost no vortices both upstream and downstream of the protrusion. However, for height ratios of <span>(:{h}_{p}/{h}_{s})</span>= 1.5 and 2.0, vortex structures are observed near the isosceles, backward, and forward protrusions. The vortex grows with the increase in <span>(:{h}_{p}/{h}_{s})</span>. As the protrusion height ratio increases, the high-temperature region becomes thicker, particularly in the downstream area. As the height ratio increases, both flow and surface peak properties are elevated. Higher Mach numbers significantly reduce the boundary layer thickness. Moreover, Mach number has a pronounced impact on <span>(:{C}_{p,:max})</span>and <span>(:{C}_{h,:max})</span>. The protrusion drag increases with higher protrusion surface temperature, greater protrusion height ratios, and elevated Mach numbers across all configurations. Conversely, drag decreases as the Knudsen number rises.</p>\u0000 </div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 3","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Turbulence and Fuel Properties on Pre-vaporized Jet Flame Surface Statistics","authors":"J. Schihl,&nbsp;A. W. Skiba,&nbsp;C. D. Carter,&nbsp;P. M. Allison","doi":"10.1007/s10494-026-00747-x","DOIUrl":"10.1007/s10494-026-00747-x","url":null,"abstract":"<div>\u0000 \u0000 <p>This research effort presents a detailed and systematic analysis of the impact of turbulence on surface characteristics of premixed flames produced with vaporized liquid fuels. The turbulent Reynolds Number (<i>Re</i>_<i>T</i>) varied between 760 and 4,200, with equivalence ratios of 0.9 and 1.1. Hydroxyl (OH) planar laser-induced fluorescence (PLIF) was employed to mark the flame front. Flame surface density (FSD), average progress variable (<span>(overline{c})</span>), flame-front curvature (<i>κ</i>), fractal dimension (FD), and inner cut-off scale (ε_i) were extracted from those images, which enabled additional analysis, including: turbulent flame area ratio and brush thickness. It was found that increasing the turbulent Karlovitz Number (<i>Ka</i>_<i>T</i>) broadened probability density functions (PDFs) of flame-front curvature, increased FSD across reaction variable space, increased turbulent area ratio and decreased brush thickness. Notably, for lean conditions, all surface statistics converged as <i>Ka</i>_<i>T</i> exceeded 10. Similarly, global consumption speed was analyzed and found to be consistent with previous findings in methane-air mixtures. Analysis of “flamelet” consumption speed shows that despite having different thermochemical properties, all of the flames considered behave similarly at a macroscopic level when properly normalized by a suitable <i>S</i>_<i>L</i>. Lastly, a fractal analysis revealed consistent FD values that approximately equal the theoretical value of 7/3 for these types of flames. Also, such analysis indicated that the normalized inner cut off scales are not sensitive to fuel type and, as in prior studies of gaseous fueled flames, decrease with increasing <i>Ka</i>_<i>T</i>.</p>\u0000 </div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 3","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10494-026-00747-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large Eddy Simulation Analysis of Turbulence Generated by a Two-Plane Active Grid Using an Optimized Motion Protocol","authors":"Alper Akardere,&nbsp;Aziz Mert Karul,&nbsp;Özgür Ertunç","doi":"10.1007/s10494-026-00744-0","DOIUrl":"10.1007/s10494-026-00744-0","url":null,"abstract":"<div>\u0000 \u0000 <p>Active grid turbulence generators that utilize rotating or flapping winglets can achieve higher turbulence levels in a controlled manner. Most active grid studies are experimental, and active grids in those were designed based on empirical data and calculations based on order-of-magnitude analysis. We used large-eddy simulations (LES) to assess the effects of square and circular winglet shapes and motion protocol. Differences in generated turbulence at distances of up to 5 mesh sizes from the active grid in the flow direction were analyzed in terms of turbulence intensity, Taylor-scale Reynolds number, spectra, isotropy level, and flow homogeneity. For these analyses, a two-plane active grid design was used to prevent full closure during operation in a wind tunnel. The numerical simulation’s validity was assessed using a combination of numerical benchmarks, physical parameters, and experimental validation, thereby facilitating the application of Large Eddy Simulation to the design of active grids. Rather than employing either random or prescribed motion protocols, this study developed an optimization method to determine the transient angular positions of the winglets. The optimization focuses on two objective functions: achieving a specified area-closure intensity and maintaining a target mean Rossby number. Simulations for the square wiglets were conducted at a constant intensity of area closure at two mean Rossby numbers, and one simulation for a circular winglet at the same lowest Rossby number and the same intensity of area closure. Five mesh size downstream of the active-grid, circular winglets generated approximately twice the Taylor-scale Reynolds number (<span>(text{Re}_{lambda}approx 375)</span>) compared to square winglets (<span>(text{Re}_{lambda}approx 180)</span>) at the same mean Rossby number. However, this increase in turbulence level was accompanied by higher levels of anisotropy and inhomogeneity in the turbulent kinetic energy and mean velocity fields. The downstream set of rods was found to be responsible for the higher velocity fluctuations in the lateral direction perpendicular to their rotation axis, both for square and circular grids. The global isotropy level for circular winglets showed a deviation of 25–30% from unity, which is significantly greater than that observed in square winglet configurations. The results revealed a clear trade-off between increasing turbulence level and preserving flow homogeneity and isotropy. Additionally, the implementation of a two-plane active grid system, combined with different winglet geometries and an optimization-based motion protocol, demonstrated significant potential for effectively modulating these flow characteristics.</p>\u0000 </div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 3","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10494-026-00744-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Internal Flow Characteristics and Vortex Evolution of Fuel Injector with Dynamic Needle Oscillation","authors":"Ziman Wang,&nbsp;Tong Liang,&nbsp;Changzhao Jiang","doi":"10.1007/s10494-026-00739-x","DOIUrl":"10.1007/s10494-026-00739-x","url":null,"abstract":"<div><p>To enable efficient and clean combustion in internal combustion engines, precise control over fuel injection and atomization is essential. Dynamic oscillation of the injector needle is a primary factor governing internal flow and atomization performance; however, its underlying mechanisms are substantially more complex than the commonly assumed static eccentricity model, and remain insufficiently understood. This study systematically examines this dynamic phenomenon by analyzing the impact of needle oscillation on the internal flow dynamics and vortex evolution in both single-hole and multi-hole injectors, with particular attention to the critical needle opening and closing stages. The results reveal that dynamic needle oscillation induces reverse-rotating large-scale vortices within the sac, which further interact to form small-scale vortex pairs. In the four-hole injector, flutter consistently suppresses the mass flow rate across all orifices, exhibiting pronounced asymmetry; the orifices located outside the flutter plane experience the strongest reduction, especially at low needle lifts. Moreover, under high-pressure (200 MPa) compressible conditions, the suppressive effect of flutter on mass flow rate becomes more significant, accompanied by intensified flow instability and persistent pressure oscillations. The dynamic mechanisms identified in this work overcome the limitations of conventional static simulations. These findings not only offer new insights for improving injection performance in traditional diesel engines but also provide important theoretical and engineering guidance for the design of injection systems for emerging green fuels such as liquid ammonia, methanol, and biodiesel.</p></div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 3","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147607383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterizing the Interactions Between Flow Dynamics and Soot Production in Ethylene Non-Premixed Pulsed Flames","authors":"Nicolás Gutiérrez,&nbsp;Nicolás Mancilla,&nbsp;Denisse Saavedra,&nbsp;Amanda García,&nbsp;Gonzalo Severino,&nbsp;Felipe Escudero,&nbsp;Rodrigo Demarco,&nbsp;Andrés Fuentes","doi":"10.1007/s10494-026-00740-4","DOIUrl":"10.1007/s10494-026-00740-4","url":null,"abstract":"<div>\u0000 \u0000 <p>This study investigates the effect of flow dynamics on the soot temperature and volume fraction fields in a non-premixed pulsed ethylene flame generated on a Yale burner. Soot properties were characterized through absorption/emission techniques, while Particle Image Velocimetry with zirconium dioxide tracer particles was applied to the entire flame. The resulting velocity fields were used to calculate shear strain rates in different regions of the flame. The results showed that modulation significantly affected the soot distribution, with a variation of <span>(sim)</span>12% in the soot volume fraction between consecutive phases of the cycle. During certain phases a higher injection flow rate is favored by the acoustic pulse, leading to an increased amount of fuel being burned and a higher soot formation. This behavior is related to the flow expansion in the upper regions of the flame, where high velocity zones coincide with an increment in soot temperature due to particle transport and accumulation. Also, areas exhibiting heightened strain rates are linked to elevated levels of mixing and oxidation. These regions are associated with a low soot volume fraction. This is likely due to enhanced mixing and oxidation under elevated strain rates, as suggested by previous numerical work, highlighting the suppression of soot inception and the predominance of oxidation processes during specific phases of the forcing cycle. The interactions between fluid structures and soot-rich zones were identified as a crucial aspect of overall combustion dynamics, with a direct impact on efficiency and emissions.</p>\u0000 </div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 3","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147606993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural Design and Performance Optimization of High-Flow Multi-Hole Nozzle Ejectors","authors":"Huali Zhang,&nbsp;Lili Jiao,&nbsp;Xuewen Zhang,&nbsp;Xiang Li,&nbsp;Peiyong Ni,&nbsp;Zhimin Xu","doi":"10.1007/s10494-026-00743-1","DOIUrl":"10.1007/s10494-026-00743-1","url":null,"abstract":"<div>\u0000 \u0000 <p>As an efficient and stable fluid delivery device, the ejector plays a critical role in various gas supply systems. However, existing ejector designs often fail to meet performance requirements under all operating conditions. This study focuses on optimizing the ejector structure for applications involving high flow rates and limited installation space, thereby expanding its applicability. The key geometric dimensions of the ejector were determined using the Sokolov method. A three-dimensional fluid simulation model was developed and validated through experimental testing. Under various operating conditions, the effects of Nozzle Exit Position (NXP), mixing chamber diameter (D_m), mixing chamber length (L_m), and Flow-Distributing Net curvature (K) on ejector performance were analyzed. The optimal structural parameters that meet the design requirements were identified. The results show that when the primary flow pressure is 350 kPa, the optimal design parameters for the ejector are NXP = 15 mm, D_m = 60 mm, L_m = 60 mm, and K = 0. These values yield the best overall performance. This research provides valuable technical support for the application of ejectors in gas fuel supply systems.</p>\u0000 </div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 3","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147606992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Insights and Machine Learning-Based Predictions of Momentum-Controlled Dual Co-Flow Jet Airfoil","authors":"Anees Waqar,&nbsp;Muhammad Hammad Ajmal,&nbsp;Muhammad Umer Sohail","doi":"10.1007/s10494-026-00742-2","DOIUrl":"10.1007/s10494-026-00742-2","url":null,"abstract":"<div>\u0000 \u0000 <p>Conventional airfoils suffer from aerodynamic limitations, including early stall onset and increased drag at higher angles of attack, which restrict their operational efficiency and versatility. Active flow control methods, such as the Co Flow Jet (CFJ), have shown promise in overcoming these challenges. This study investigated whether a Dual Co Flow Jet (DCFJ) system with independently controlled suction and blowing slots may extend the stable working range of the airfoil. Building on these foundations, airfoils were tested at various free stream velocities and angles of attack, ranging from 0° to 24°, each corresponding to multiple coefficients of jet momentum. Compared to the baseline airfoil, the DCFJ configuration not only greatly improves lift-to-drag ratios but also raises maximum lift coefficients and delays stall. To further reduce the cost and complexity of full-scale testing, numerous machine learning (ML) models, including multi-layer artificial neural networks, were trained on experimental datasets. These models achieved minimal prediction errors for lift and drag coefficients, providing a reliable and computationally efficient alternative to conventional experimental workflows.</p>\u0000 </div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 3","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147562063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stochastic Fields/LES of Partially-Premixed Lean Hydrogen Flames with Swirl-Axial Air Injection","authors":"Weiyue Liu,&nbsp;W. P. Jones,&nbsp;Aimee S. Morgans","doi":"10.1007/s10494-026-00736-0","DOIUrl":"10.1007/s10494-026-00736-0","url":null,"abstract":"<div>\u0000 \u0000 <p>Turbulent hydrogen flames with varying operating conditions in the swirl-axial air injection AHEAD combustor were studied computationally with a multi-regime flame closure method, combustion LES / Stochastic fields. The method was validated by comparisons with measurements in isothermal and reacting flows. The velocity fields, flames, mixing fields and thermo-chemical states were analysed in detail. Further comparisons were carried out for different operating conditions to study the effect of global equivalence ratio and axial air injection ratio. On the one hand, it introduces higher axial momentum, which restricts flashback. On the other hand, increasing the global equivalence ratio or axial air injection ratio negatively affects the spatial mixing quality where the axial momentum flux plays an important role. The results also suggest that thermo-chemical states are dominantly controlled by the global equivalence ratio rather than the inlet reactant temperature or flow conditions. The effect of differential diffusion was also studied. Differential diffusion slightly increases the possibility of the upstream occurrence of the flame inner branch, which results in the inner flame branch brush becoming broader. This was found to be related to the changes of the upstream mixing field due to differential diffusion. Nevertheless, the global system is negligibly influenced by differential diffusion due to the high Reynolds number.</p>\u0000 </div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 3","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10494-026-00736-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147441432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}