Flow, Turbulence and Combustion最新文献

{"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}

{"title":"Experimental Closure of Mean Reaction-Progress Balance in (mathbf{NH}_3/mathbf{CH}_4) Turbulent Premixed Flames","authors":"Minshuo Li,&nbsp;Jingruo Chen,&nbsp;Yuanzhe He,&nbsp;Yutao Zheng,&nbsp;Shijie Xu,&nbsp;Ning Liu,&nbsp;Weiwei Cai","doi":"10.1007/s10494-026-00737-z","DOIUrl":"10.1007/s10494-026-00737-z","url":null,"abstract":"<div>\u0000 \u0000 <p>Ammonia/methane (<span>(textrm{NH}_3)</span>/<span>(textrm{CH}_4)</span>) co-combustion offers a promising route toward high-efficiency, low-carbon, and low-NO_<i>x</i> combustion, yet experimental insights into local displacement speeds in ammonia-containing flames remain scarce. Here, 2D particle image velocimetry (2D-PIV) was applied to turbulent premixed Bunsen flames at atmospheric pressure, covering ammonia fractions up to 0.6 and equivalence ratios between 0.7 and 1.0. Streamline-based decomposition of the progress-variable transport equation showed that the measured flame propagation speed <i>s</i>_<i>T</i> is broadly consistent with the closure relation <i>s</i>_<i>R</i> + <i>s</i>_<i>F</i> at low turbulence intensities, supporting the applicability of the Bray-Moss-Libby (BML) thin-flame concept to <span>(textrm{NH}_3)</span>/<span>(textrm{CH}_4)</span> flames. The reaction and convection terms dominated the balance, while turbulent fluxes, though weaker, remained non-negligible. Closure errors increased with higher ammonia content or leaner mixtures but were greatly reduced by introducing Markstein corrections and approximating 2D flame surface density as 3D. Analysis of reaction rates further revealed that the near-axis region contributed most, while ammonia addition lowered local reactivity, increased flame height, and promoted local extinction at the root. The findings provide experimental guidance for source-term estimation and turbulence–flame interaction modeling.</p>\u0000 </div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 3","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440836","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":"Turbulent Flow and Air Exchange Within Alternating Building-Vegetation-Constrained Canyons: Evaluation of Leaf-Area-Density Impacts","authors":"G. Duan,&nbsp;Z. Bi,&nbsp;H. Wang,&nbsp;L. Zhao,&nbsp;X. Zheng,&nbsp;T. Takemi","doi":"10.1007/s10494-026-00735-1","DOIUrl":"10.1007/s10494-026-00735-1","url":null,"abstract":"<div><p>Introducing a vegetation barrier in place of one building obstacle within a canonical street canyon of identical geometry yields a coupled vegetation-building (V–B) or building–vegetation (B–V) configuration, depending on whether the vegetation is located on the upwind or downwind side of the canyon, whose flow structure and turbulence characteristics remain less explored compared with the canonical building-building (B–B) case. The extent to which results in V–B and B–V canyons deviate from or converge with those of a generic B–B canyon remains unclear. Using large-eddy simulation across a range of leaf area densities (<i>LAD</i>), this study examines how vegetation placement and porosity modulate canyon-scale vortex geometry, turbulence structure, and air exchange. The zero-<i>w</i> trace delineating the primary canyon vortex, which aligns approximately with the vertical axis in a unit-aspect-ratio B–B canyon, exhibits a monotonic tilt toward the vegetation side as <i>LAD</i> decreases, reflecting progressive deformation and weakening of the mean circulation. Within V–B canyons, turbulence intensity and vertical momentum flux show little dependence on <i>LAD</i>, implying that upwind vegetation primarily acts as a momentum sink that suppresses near-wall shear. In contrast, these turbulence statistics in B–V canyons exhibit stronger sensitivity to <i>LAD</i> (<span>(R^2sim 0.81)</span> and 0.65, respectively), suggesting enhanced turbulence generation through canopy-wake interaction. Both mean and fluctuating air-exchange rates increase smoothly with <i>LAD</i> for vegetated canopies but decline sharply as the system approaches the impermeable B–B limit. This non-monotonic behaviour demonstrates that the <span>(LADtoinfty)</span> limit is dynamically distinct from an impermeable wall, as dense vegetation retains finite permeability and sustains shear-layer instabilities absent in solid obstacles.</p></div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 3","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440819","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":"Sparse Sensor Placement for a Cyclonic Burner under MILD Combustion Conditions","authors":"Vincenzo Rosati,&nbsp;Giovanni Battista Ariemma,&nbsp;Giancarlo Sorrentino,&nbsp;Raffaele Ragucci,&nbsp;Mara de Joannon","doi":"10.1007/s10494-026-00733-3","DOIUrl":"10.1007/s10494-026-00733-3","url":null,"abstract":"<div>\u0000 \u0000 <p>This work assesses a POD/SVD-based sparse sensing framework for thermochemical field reconstruction in the LUCY cyclonic combustor operating under MILD methane combustion conditions. A reduced-order representation is built from CFD data and combined with QR decomposition with column pivoting (QRCP) to design sensor layouts and infer reduced coefficients from sparse measurements. Two truncation criteria are compared, the optimal hard threshold of Gavish et al. and a 99.5% cumulative variance, together with Auto-scaling preprocessing, to quantify their impact on reconstruction accuracy and out-of-sample prediction. Beyond unconstrained QRCP, practical deployment constraints are investigated through distance separation and region-limited candidate sets, and the performance of a predefined thermocouple layout is evaluated by augmenting it with additional optimally placed sensors. Results are reported for both training and testing operating conditions, complemented by an uncertainty-propagation analysis based on experimental measurement variability. The study shows that robust reconstruction is achieved with a limited number of sensors when the balance between retained rank and measurements is respected, while spatial constraints can preserve near-optimal performance and improve physical feasibility. The framework provides a computationally efficient soft-sensing strategy to support monitoring-oriented applications in confined MILD combustors.</p>\u0000 </div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 3","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10494-026-00733-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440918","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":"Correction: Experimental and Numerical Investigation of the Acoustic Response of a Hollow-cone Fuel Spray in a Swirling Air Flow.","authors":"Titouan Morinière,&nbsp;Davide Laera,&nbsp;Thierry Schuller","doi":"10.1007/s10494-026-00734-2","DOIUrl":"10.1007/s10494-026-00734-2","url":null,"abstract":"","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 3","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147335955","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":"High-Speed RDC Data Averaging Through Dynamic Time Warping","authors":"Mauro Tagliaferri,&nbsp;Provence Barnouin,&nbsp;Eric Bach,&nbsp;Myles D. Bohon,&nbsp;Christian Oliver Paschereit","doi":"10.1007/s10494-026-00732-4","DOIUrl":"10.1007/s10494-026-00732-4","url":null,"abstract":"<div>\u0000 \u0000 <p>High-speed diagnostics are essential for understanding the unsteady parameter fluctuations in Rotating Detonation Combustors (RDCs). However, the experimental data from RDCs often exhibit significant stochasticity spatially and temporally due to factors such as lap-to-lap detonation wave fluctuations, measurement uncertainties, and sensor-induced artifacts. Traditional phase-averaging techniques, like the arithmetic mean, can distort the true detonation wave structure by smoothing out key features due to temporal misalignment. This study investigates the application of a soft-Dynamic Time Warping (soft-DTW) based averaging as a unique method for processing high-speed RDC data. Compared to conventional methods, soft-DTW has shown improved resilience to local time axis distortions, which may enable better alignment and preservation of the intrinsic wave structure, particularly by capturing the sharpness of the main peak and secondary features relevant to the detonation process. The study evaluates the capability of soft-DTW to capture essential physical characteristics of rotating detonation waves using dynamic pressure and video data. Additionally, a sensitivity analysis assesses the method’s effectiveness in accurately representing secondary features, such as reflected shock waves, highlighting its potential for more representative RDC data averaging.</p>\u0000 </div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 2","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10494-026-00732-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147338911","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":"Drag Reduction Effect of Turbulent Flow by Synchronized Wall-Oscillation in Annular Pipe","authors":"Hiroya Mamori,&nbsp;Ayaka Higashimoto,&nbsp;Junichi Morita,&nbsp;Menglei Wang,&nbsp;Takeshi Miyazaki,&nbsp;Koji Fukudome,&nbsp;Yusuke Nabae","doi":"10.1007/s10494-026-00729-z","DOIUrl":"10.1007/s10494-026-00729-z","url":null,"abstract":"<div>\u0000 \u0000 <p>Direct numerical simulations of the concentric annular turbulent pipe flow are performed to investigate the skin-friction drag reduction effect by the wall oscillation control technique. The oscillation on the inner and outer walls is synchronized, and the control effect is investigated for different radius ratios. While drag reduction by wall oscillation has been extensively studied in canonical wall-bounded flows such as plane channels and circular pipes, its effects in geometrically non-uniform configurations, such as the annular pipe, remain less understood. Curvature and frictional asymmetry give rise to characteristic flow responses. The simulations demonstrate that the friction drag decreases owing to the wall oscillation. The maximum drag reduction rate is <span>(R_D approx 0.5)</span> at the optimal period of <span>(T^+ approx 150)</span>. An identity equation for the skin-friction coefficient of the annular pipe flow is derived, and the contribution from turbulence is quantitatively discussed. Scaling methods for the drag reduction rate are applied: 1) increment of the mean velocity and 2) based on the Stokes problem. Both scaling methods appropriately describe the drag-reduction behavior in the drag-reduction regime at <span>(T^+ lessapprox 150)</span>.</p>\u0000 </div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 2","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147336211","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":"Large Eddy Simulation of Lean Premixed Hydrogen/Methane Bunsen Flames: Effects of Hydrogen Content and Pressure","authors":"Yecan Liu,&nbsp;James C. Massey,&nbsp;Filippo Faldella,&nbsp;Yusuke Tanaka,&nbsp;Nedunchezhian Swaminathan","doi":"10.1007/s10494-026-00730-6","DOIUrl":"10.1007/s10494-026-00730-6","url":null,"abstract":"<div>\u0000 \u0000 <p>Hydrogen/methane (H₂/CH₄) blends serve as a transitional fuel for gas turbines, offering a pathway toward cleaner energy by reducing carbon emissions while leveraging existing natural gas infrastructure. Understanding the effects of H₂ content and pressure on the flame shape is essential for safe operation and optimising combustion performance. In this work, turbulent lean premixed Bunsen H₂/CH₄ flames are studied using large eddy simulation (LES), focusing on the flame brush length (<i>f</i>_<i>l</i>) and thickness (<i>f</i>_<i>b</i>) along the centreline. The results have been compared with available measurements for validation. The findings indicate that increasing H₂ content leads to shorter and thinner flames, while the pressure effects are minimal. At the lower H₂ content (≤30% by volume), the change in <i>f</i>_<i>l</i> is relatively small, whereas at the higher H₂ content ( &gt; 30% by volume), <i>f</i>_<i>l</i> decreases linearly with increasing H₂ content. Similarly, the values of <i>f</i>_<i>b</i> decrease as H₂ content is increased. This phenomenon is primarily due to the increased turbulent flame speed (<i>s</i>_<i>T</i>) resulting from enhanced fuel reactivity. The limited pressure effects on <i>f</i>_<i>l</i> and <i>f</i>_<i>b</i> are attributed to the consistent <i>s</i>_<i>T</i>, maintained by the synergistic interactions between chemical reactions and turbulent characteristics. Furthermore, this study highlights the transition of the flame regime from the corrugated flamelet regime to the thin reaction zone regime along the axial direction. This transition occurs further upstream in flames with higher H₂ content, driven by the increased flame speed. Additionally, the reaction progress variable contours and profiles show that the H₂ addition also leads to a radial thinning of the flame, while pressure has little effect on the overall flame shapes.</p>\u0000 </div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"116 2","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10494-026-00730-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082499","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}