Fluid Dynamics最新文献_第2页

Lateral Migration and Focusing of Inerial Particles in Two-Phase Flows of Boundary-Layer Type 边界层型两相流中惯性粒子的横向迁移和聚焦

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-09-04 DOI: 10.1134/S0015462826606042

A. N. Osiptsov, O. D. Rybdylova

{"title":"Lateral Migration and Focusing of Inerial Particles in Two-Phase Flows of Boundary-Layer Type","authors":"A. N. Osiptsov, O. D. Rybdylova","doi":"10.1134/S0015462826606042","DOIUrl":"10.1134/S0015462826606042","url":null,"abstract":"The lifting force exerted on particles in shear flows can significantly affect the admixture distribution in near-wall gas/liquid-particle/droplet flows. For small particle Reynolds numbers based on the relative velocity, shear rate, and particle angular velocity, the expression for the lifting force was first obtained by P. Saffman in 1965 and corrected in 1968. In this study, we use a modified (extended to finite Reynolds numbers) expression for the lifting force proposed by R. Mei in 1992. In the framework of the one-way coupled two-fluid model we consider three examples of laminar gas/liquid-particle flows of boundary layer type with inertial inclusions: the two-phase Blasius problem on a horizontal and a vertical plate, gas-particle flow in a near-wall dusty plane jet, and inertial-particle focusing in an axisymmetric profiled microchannel. In all examples considered the lifting force exerted on the particles plays a crucial role and results in lateral migration and focusing of the dispersed admixture. The calculations of the particle concentration in the Blasius problem are compared with available experimental data. The study is based on the two-phase boundary layer approximation and the Full Lagrangian approach (FLA), proposed in previous publications of the authors. This approach makes it possible to calculate all particle parameters, including the number density, from the solution of systems of ordinary differential equations on chosen particle trajectories. The flow structure in the regions of crossing particle trajectories and the locations of caustics can also be studied by this method. The results obtained may be of interest for the development of technologies which use near-wall dilute two-phase flows and focused particle beams.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 5","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0015462826606042.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148903525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Energy Stability Analysis of Thermal Convection in an Inclined Fluid Layer with a Temperature-Dependent Internal Heat Source 具有温度相关内热源的倾斜流体层热对流能量稳定性分析

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-09-04 DOI: 10.1134/S0015462826605930

G. Kaur, A. Batra, R. Bajaj

引用次数: 0

Numerical Prediction of Turbulent Thermal Mixing in the T-Junction Using ANSYS-CFX Code 基于ANSYS-CFX代码的t型结湍流热混合数值预测

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-09-04 DOI: 10.1134/S0015462826605772

M. Boumaza, A. L. C. Deghal, A. Dahia, S. Medguedem

{"title":"Numerical Prediction of Turbulent Thermal Mixing in the T-Junction Using ANSYS-CFX Code","authors":"M. Boumaza, A. L. C. Deghal, A. Dahia, S. Medguedem","doi":"10.1134/S0015462826605772","DOIUrl":"10.1134/S0015462826605772","url":null,"abstract":"The main objective of this study is to characterize thermal mixing downstream of a T-junction through which two fluids flow at different temperatures inducing cyclical thermal stresses. The generated turbulent mixing is frequently observed in many industrial applications, particularly in nuclear field. The inevitable temperature variations in fluid circuits can induce cyclic thermal stresses in the walls, particularly, at the points where the flows at different temperatures meet and in areas of thermal stratification. This study aims to estimate the predictive performance of the CFD (computational fluid dynamics) code used to model the turbulent mixing phenomenon, with a view to contributing to its validation. The use of numerical simulation makes it possible to analyze the physical mechanisms involved in detail and to extrapolate the results beyond the experimental configurations available. For this purpose, ANSYS-CFX code was used with the LES (large eddy simulation) model. The numerical predictions were compared with reference experimental data from the Vattenfall installation. A good agreement between the two results was found. This work contributes to the understanding of the thermal mixing phenomenon in T-junctions and shows the predictive capability of the CFD codes to predict thermal hydraulic parameters and the responses of the plant performances.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 5","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148903526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analysis of Aerodynamic Characteristics of a Blunt-Trailing-Edge Wind Turbine Airfoil at High Angles of Attack 钝尾缘风力机翼型大迎角气动特性分析

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-09-02 DOI: 10.1134/S0015462826605462

G. Y. Ji, Q. W. Cui, J. X. Zhou

{"title":"Analysis of Aerodynamic Characteristics of a Blunt-Trailing-Edge Wind Turbine Airfoil at High Angles of Attack","authors":"G. Y. Ji, Q. W. Cui, J. X. Zhou","doi":"10.1134/S0015462826605462","DOIUrl":"10.1134/S0015462826605462","url":null,"abstract":"An aerodynamic analysis model for thick airfoils is established to address the unsteady deep-stall aerodynamics induced by high angles of attack (160°–200°) on horizontal-axis wind turbine (HAWT) blades at high wind speeds. Two-dimensional unsteady numerical simulations of the NACA 4424 airfoil are conducted using the shear stress transport-delayed detached eddy simulation method. A multidimensional flow-field evaluation matrix covering the deep-stall to modal-transition regime is constructed. The time-averaged lift, drag, and quarter-chord pitching-moment coefficients, together with their fluctuation RMS values, are evaluated over statistically stationary intervals. Dominant frequencies (denoted as fp) are identified and non-dimensionalized using Welch’s method for power spectral density. The results demonstrate that within the 160°–190° range, instability and entrainment of the separated shear layers, along with the alternating shedding of vortex cores, constitute a dynamical closed loop for strongly coherent quasi-periodic load fluctuations; at 195°, the flow enters a critical transition state marked by fluctuation energy divergence; at 200°, the flow triggers a modal breakdown into a “broadband incoherence” state dominated by the disintegration of large-scale coherent vortices. The established “statistical steady-state—fluctuation RMS intensity—spectral characteristics—flow structure” consistency evaluation framework provides a reliable basis for load characterization and trailing-edge parameterized design under high-wind reverse flow conditions.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 4","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148926273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analytical Analysis of the Impact of Capillary Pressure Nonlinearity on Counter-Current Imbibition 毛细管压力非线性对逆流吸积影响的解析分析

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-09-02 DOI: 10.1134/S0015462826605127

N. Sahu, M. F. El-Amin, S. R. Yadav

{"title":"Analytical Analysis of the Impact of Capillary Pressure Nonlinearity on Counter-Current Imbibition","authors":"N. Sahu, M. F. El-Amin, S. R. Yadav","doi":"10.1134/S0015462826605127","DOIUrl":"10.1134/S0015462826605127","url":null,"abstract":"The modelling of counter-current spontaneous imbibition in porous media is primarily driven by nonlinear partial differential equations. The formulation for the capillary pressure plays a crucial role in fluid transport dynamics. This study employs the reduced differential transform method to derive semi-analytical solutions for the one-dimensional imbibition equation. To assess how capillary pressure nonlinearity affects the water saturation profiles and the propagation of the imbibition front, we examine three different constitutive models: a baseline linear model, a logarithmic model, and an exponential model. The reduced differential transform method is applied to convert the governing nonlinear partial differential equations into algebraic recurrence relations, producing power-series solutions that maintain the system’s nonlinear characteristics. A comparative analysis shows that the logarithmic formulation leads to aggressive, singularity-driven displacement rates. Conversely, the exponential model mathematically captures the vanishing mobility of the non-wetting phase as the system approaches maximum wetting saturation, ensuring physical consistency and mathematical stability. Convergence analysis confirms that the truncated reduced differential transform method series is reliable across all tested nonlinearities. These findings demonstrate the effectiveness of the reduced differential transform method in addressing strongly nonlinear multiphase flow phenomena, making it a robust semi-analytical tool for analyzing displacement dynamics in porous media.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 4","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148926275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Study on the Turbulent Boundary Layer with an Adverse Pressure Gradient on a Permeable Plate in Compressible Gas Flow 可压缩气体流动中可渗透板上逆压梯度湍流边界层的研究

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-09-02 DOI: 10.1134/S0015462826605796

V. G. Lushchik, S. S. Popovich, A. M. Chaika

引用次数: 0

Effect of the Stagnation Temperature on the Conical Shock Wave Produced in a Real Gas 滞止温度对实际气体中锥形激波产生的影响

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-09-02 DOI: 10.1134/S0015462826604286

M. Mechta, A. Dahia

{"title":"Effect of the Stagnation Temperature on the Conical Shock Wave Produced in a Real Gas","authors":"M. Mechta, A. Dahia","doi":"10.1134/S0015462826604286","DOIUrl":"10.1134/S0015462826604286","url":null,"abstract":"This study aims to develop a novel numerical algorithm based on a mathematical model to ascertain the characteristics of supersonic flow passing through a conical shock wave by considering the real gas effects in contrast to the perfect gas assumption. Air is considered to be the working fluid. The model incorporates variations in the specific heat at constant pressure due to changes in the temperature and the density. The stagnation temperature is a crucial factor in the analysis. The mathematical framework involves solving a system of first-order nonlinear differential equations with three interrelated variables using initial conditions. The numerical solution is achieved by means of adaptation of the higher order Runge–Kutta method. The parameters associated with the conical shock wave can be determined by employing a new model featuring an oblique shock waves under the real gas conditions. A comparative analysis with the perfect gas model is conducted at low stagnation temperatures, upstream Mach numbers, and cone deviation angles, including an estimation of the divergence between the real and perfect gas models. The study is focused on using air as the working fluid.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 4","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148926349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Performance Study of Modified Discrete Co-Flow Jet Configuration for Wind Turbine Applications 用于风力机的改进型离散共流射流结构性能研究

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-09-02 DOI: 10.1134/S0015462826604894

S. A. Tejnarayan, K. Balaji

引用次数: 0

Numerical Simulation of Cavitating Flow in an Ejector Based on the Population Balance Method 基于人口平衡法的喷射器空化流数值模拟

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-09-02 DOI: 10.1134/S0015462826604328

X. Fang, C. W. Sun, Z. J. Cai, L. H. Fan, B. Liu, X. L. Zhang, H. L. Yu

{"title":"Numerical Simulation of Cavitating Flow in an Ejector Based on the Population Balance Method","authors":"X. Fang, C. W. Sun, Z. J. Cai, L. H. Fan, B. Liu, X. L. Zhang, H. L. Yu","doi":"10.1134/S0015462826604328","DOIUrl":"10.1134/S0015462826604328","url":null,"abstract":"Jet cavitation flow significantly enhances heat and mass transfer efficiency in reactions through bubble formation, collapse, and implosion. To elucidate the periodic evolution of cavitation flow in jet devices and guide structural optimization, this study employs a population balance model (PBM) coupled with a cavitation model for numerical simulation. The spatiotemporal evolution of the pressure, the vapor volume fraction, the bubble volume, and the particle size distribution during the process considered is comprehensively analyzed. Furthermore, the effects of the contraction angle, the diameter ratio, the diffuser angle, and the throat aspect ratio on cavitation flow are systematically investigated. The results show that acceleration in the contraction section leads to the maximum velocity and the minimum pressure at the throat. When the local pressure falls below the saturated vapor pressure, phase-change cavitation occurs, and the growth/collapse/implosion of bubbles induces periodic pressure fluctuations. A reduction in the cavitation number significantly intensifies cavitation, while an increase in the cavitation number leads to instability and shedding. The particle sizes are predominantly distributed within the 0.001–0.008 mm range (approximately 60%), the 0.008–0.050 mm range exhibiting the lowest proportion. A structural sensitivity analysis reveals that the diameter ratio predominantly governs the throat pressure and the cavitation intensity, the diffuser angle influences pressure recovery and stability, the contraction angle alters the flow resistance and gradient, and the throat aspect ratio has a relatively minor effect. The optimal parameter combination (θ = 45°, β = 0.2, φ = 30°, and γ = 0.5) provides quantitative reference for enhancing cavitation performance and engineering design of jet devices.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 4","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148926582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evolution of the Spreading Pattern of a Freely Falling Oil Drop in Water in the Impact Flow Mode 冲击流模式下自由落体油滴在水中扩散模式的演化

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-09-02 DOI: 10.1134/S0015462826605577

Yu. D. Chashechkin, A. Yu. Ilinykh

{"title":"Evolution of the Spreading Pattern of a Freely Falling Oil Drop in Water in the Impact Flow Mode","authors":"Yu. D. Chashechkin, A. Yu. Ilinykh","doi":"10.1134/S0015462826605577","DOIUrl":"10.1134/S0015462826605577","url":null,"abstract":"High-speed video recording is used to trace in detail the initial stage of the flow pattern evolution during the spreading of a freely-falling oil drop in a cuvette containing tap water. The experiments were conducted in impact mode, when the kinetic energy of a drop (KED) exceeds its potential surface energy (PSE). In the initial stage of the spreading the drop, distorting the free surface, forms an energy-laden layer in the contact area, comprising both fluids in contact. The boundary of the contact area disintegrates into individual oil drops containing water. Droplets emerge from the tips of the trickles. The droplets emission proceeds cyclically, with each new group of droplets emerging at an increasingly greater angle to the horizon. The droplet diameters increase with time and their velocities decrease. Examination of the enlarged images reveals that the droplets forming an “oil mist” contain both oil and water. The inflowing oil spreads over the cavity surface and comes in a droplets, from the vertex of which a new drop containing both oil and water is ejected. A dam connecting the drop with the splash remainder contains oil droplets encased in a water trickle. The submerging splash and the returning drop form new cavities of rapidly varying shape. In the intermediate stage of evolution an oil drop separates from the cavity bottom, stops gradually, and then floats up. The boundary of the oil film spreading over the fluid surface is broken by thin fractures into separate sectors. The positions of the fracture lines are determined by depressions at the boundary of the oil-water spreading region on the crown surface. The variations of the cavity and crown dimensions are traced during the initial stage of the flow pattern evolution.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 4","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148926580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0