Fluid Dynamics最新文献_第3页

Simulation and Analysis of Flow Field Evolution and Particle Dynamics in the Molding Cavity of Solid CO2 固体CO2成型腔内流场演化与颗粒动力学模拟分析

IF 0.6 4区工程技术

Fluid Dynamics Pub Date : 2026-03-19 DOI: 10.1134/S0015462825604085

X. W. Hu, L. F. Mei, D. B. Yan, J. F. Huang

{"title":"Simulation and Analysis of Flow Field Evolution and Particle Dynamics in the Molding Cavity of Solid CO2","authors":"X. W. Hu, L. F. Mei, D. B. Yan, J. F. Huang","doi":"10.1134/S0015462825604085","DOIUrl":"10.1134/S0015462825604085","url":null,"abstract":"The gas-solid two-phase flow characteristics within the compression cavity of a solid carbon dioxide (CO2) molding machine are investigated using numerical simulation. Initially, based on computational fluid dynamics (CFD), the effects of varying inlet inclination angles (0–60°) on the flow field structure within the cavity are analyzed, with a particular focus on examining the evolution of the velocity field, the pressure distribution, and the gas trajectory patterns. Subsequently, the discrete phase model (DPM) is applied to track the motion of snowflake-shaped dry ice particles, enabling a detailed examination of particle spatial distribution under flow interactions. Results indicate that an increase in the inlet inclination angle significantly enhances the main flow diffusion within the cavity, improving particle phase dispersion uniformity. However, further increases in the angle lead to a concomitant rise in the static pressure gradients, raising the risk of high-pressure injection events. An analysis of gas motion trajectories shows that, at the 45 and 60° inlet angles, the flow field exhibits a typical vortex-diffusion composite pattern. The primary gas flow forms stable spiral trajectories that enhance particle dispersion, while secondary flows effectively reduce particle deposition at the cavity bottom. In terms of the particle distribution, particles accumulate near the exhaust hole at the angle of 45°, increasing the cavitation risk, whereas at the angle of 60°, they concentrate primarily on the right side while maintaining optimal dispersion uniformity throughout the cavity. Comprehensive evaluation identifies the angle of 60° as the optimal inlet inclination for aerodynamic performance. This work provides critical theoretical foundation and engineering guidance for the aerodynamic optimization of solid CO2 molding equipment.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147560308","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

Contact Time Reduction through Droplet Horseshoe-Shaped Rebound on Superhydrophobic Surfaces with a Cubic Structure 立方结构超疏水表面上液滴马蹄形回弹减少接触时间

IF 0.6 4区工程技术

Fluid Dynamics Pub Date : 2026-03-19 DOI: 10.1134/S0015462825602748

Z. Z. Min, T. X. Chen, Y. H. Shang, D. Li

{"title":"Contact Time Reduction through Droplet Horseshoe-Shaped Rebound on Superhydrophobic Surfaces with a Cubic Structure","authors":"Z. Z. Min, T. X. Chen, Y. H. Shang, D. Li","doi":"10.1134/S0015462825602748","DOIUrl":"10.1134/S0015462825602748","url":null,"abstract":"In practical applications, droplets often collide with surfaces in an asymmetric (eccentric) manner rather than striking centrally, leading to complex impact dynamics that significantly affect the droplet behavior and contact time. However, most previous studies have primarily concentrated on symmetric (central) impacts, overlooking the nuances introduced by eccentric collisions. To address this gap, this study employs a three-dimensional pseudopotential lattice Boltzmann method (LBM) to investigate the dynamics of droplets impacting superhydrophobic surfaces (SHS) adorned with a single cubic protrusion under eccentric collision conditions. Here, the effects of the Weber number We, eccentricity, and the cubic protrusion size on the droplet contact time and rebound dynamics are systematically explored. Several distinct rebound modes, including off-center toroidal rebounds and horseshoe-shaped rebounds, driven by asymmetric momentum redistribution, are identified. The results show that under strong eccentricity, the droplet achieves rapid detachment via a slanted rebound mode that bypasses liquid ring formation, resulting in a reduction in the contact time up to 65.05% as compared to flat SHS. The findings further reveal that the coupling of lateral sliding and vertical retraction enhances energy conversion efficiency and accelerates rebound. The study provides new physical insights into the mechanisms of contact time reduction and offers practical design guidelines for engineered surfaces with superior liquid repellency.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147560309","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

Effect of Plain, Concave and Convex Winglet Geometry on Wing Performance at Various Cant Angles 平、凹、凸小翼几何形状对不同斜角下机翼性能的影响

IF 0.6 4区工程技术

Fluid Dynamics Pub Date : 2026-03-01 DOI: 10.1134/S0015462825602785

Y. Zerlen, S. Tangöz

{"title":"Effect of Plain, Concave and Convex Winglet Geometry on Wing Performance at Various Cant Angles","authors":"Y. Zerlen, S. Tangöz","doi":"10.1134/S0015462825602785","DOIUrl":"10.1134/S0015462825602785","url":null,"abstract":"The winglets located at aircraft wing ends are used to increase the aerodynamic performance and reduce fuel consumption by regulating negatively affecting the performance at the wings end. Therefore, aircraft wings have a critical importance on aerodynamic efficiency. The most efficient winglet model should be used in each of the flight positions. This study is aimed to investigate the effects of concave, convex, and plain winglet geometry on wing performance. The effects of plain, concave and convex winglet models with cant angles of 30°, 45°, and 60° were experimentally investigated at the angles of attack ranging from 0 to 20°. The aerodynamic lift and drag coefficients generated by each design were measured in wind tunnel tests conducted at a Reynolds number of 2.5 × 105, and the effect of the winglet’s shape on wing performance was compared. The data obtained reveal that various wingtip designs have significant effects on the aerodynamic properties of the wing. At low, moderate and high angles of attack, the highest lift is achieved with the 30° cant angle winglet. The best results for all winglet models in terms of the aerodynamic quality were obtained in the plain winglet model. Furthermore, the aerodynamic quality generally increases with decrease in the cant angles. It is anticipated that these findings, obtained from winglet models with various geometric designs, could contribute to the development of more efficient winglet geometry.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147336051","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

Numerical Study of Droplet Breakup in Asymmetric Y-Junction Microchannels: Effect of the Branch Width Ratio and the Viscosity Ratio 非对称y结微通道中液滴破裂的数值研究：分支宽度比和粘度比的影响

IF 0.6 4区工程技术

Fluid Dynamics Pub Date : 2026-03-01 DOI: 10.1134/S0015462825603420

T. T. Nguyen, L. H. T. Do

{"title":"Numerical Study of Droplet Breakup in Asymmetric Y-Junction Microchannels: Effect of the Branch Width Ratio and the Viscosity Ratio","authors":"T. T. Nguyen, L. H. T. Do","doi":"10.1134/S0015462825603420","DOIUrl":"10.1134/S0015462825603420","url":null,"abstract":"This study presents a three-dimensional numerical investigation of droplet breakup in asymmetric Y-junction microchannels using a coupled volume of fluid-level set method. The motivation arises from the limited understanding of how geometric asymmetry and viscosity contrast jointly influence droplet splitting, which has been extensively explored only in symmetric T-junctions. The effects of the viscosity ratio ({{lambda }}) and the outlet width ratio ({{w}_{2}}{text{/}}{{w}_{1}}) on the critical capillary number ({text{Ca}}) and the droplet length ratio l/w governing the transition between the breakup and non-breakup regimes were systematically analyzed. The results reveal that the higher viscosity ratios promote breakup by enhancing the viscous stresses with respect to interfacial tension, while the larger outlet width ratios favor non-breakup as droplets tend to move into the wider branch. A modified predictive model, developed by extending the existing T-junction framework, successfully captures the regime transition behavior in asymmetric Y-junctions. Furthermore, the daughter droplet length ratio after breakup deviates increasingly from ideal geometric scaling with greater outlet asymmetry. These findings provide new insight into the coupled influence of the viscosity ratio and geometric asymmetry on droplet dynamics and offer a predictive approach for designing microfluidic systems with controlled droplet splitting.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147336054","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

Spreading Characteristics of Supersonic Jets Issued from a Circular Nozzle with Square Grooves 方槽圆形喷管超声速射流的扩散特性

IF 0.6 4区工程技术

Fluid Dynamics Pub Date : 2026-03-01 DOI: 10.1134/S0015462825604292

S. Ilakkiya, B. T. N. Sridhar

{"title":"Spreading Characteristics of Supersonic Jets Issued from a Circular Nozzle with Square Grooves","authors":"S. Ilakkiya, B. T. N. Sridhar","doi":"10.1134/S0015462825604292","DOIUrl":"10.1134/S0015462825604292","url":null,"abstract":"The effect of internal square cross-section grooves in a circular convergent-divergent nozzle as vortex generators on the spreading characteristics of supersonic jets ejected from the nozzle has been studied experimentally. The area ratio of the nozzle was equal to 1.44 and the outlet Mach number for the optimum expansion level was equal to 1.8. The experiments were carried out at three nozzle pressure ratios equal to 3.6, 5.5, and 7.2 corresponding to the over expansion, near optimum, and under expansion conditions, respectively, using both a plain circular nozzle and a nozzle with two diametrically opposite grooves. The radial Pitot pressure distributions were obtained at various axial distances from the nozzle exit. At overexpansion and near optimum expansion, the spread was lowered by introduction of grooves. At underexpansion conditions, the grooves increased the jet spread. The shear layer width of the jets from both plain and grooved nozzles increased with the growth of the axial distance but the variations revealed that the effect of grooves was to reduce the width at all axial locations at the over expansion and near optimum expansion levels. At the under expansion conditions, the jet from the grooved nozzle exhibited the higher shear layer width. The variation in the jet full width of both the jets exhibited a similar behaviour as that of the shear layer width. From the experimental data, it can be inferred that the grooves increased the spread at the underexpansion conditions and decreased the spread at the overexpansion and near optimum expansion conditions.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147336053","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

Effect of the Orifice Aspect Ratio on the Flow Development in Triangular Jets 孔板展弦比对三角形射流流动发展的影响

IF 0.6 4区工程技术

Fluid Dynamics Pub Date : 2026-03-01 DOI: 10.1134/S0015462825603109

M. Azad

{"title":"Effect of the Orifice Aspect Ratio on the Flow Development in Triangular Jets","authors":"M. Azad","doi":"10.1134/S0015462825603109","DOIUrl":"10.1134/S0015462825603109","url":null,"abstract":"The results of an experimental study of incompressible, isothermal turbulent free jets issuing from sharp-edged isosceles triangular orifices with the 10°, 70°, and 160° apex angles are presented. The aspect ratios, defined herein as the ratios of the base to the height of the triangular orifices, are equal to 0.18, 1.40, and 11.32 for the 10°, 70°, and 160° orifices, respectively. The results for a round jet, also issuing from a sharp-edged orifice, are presented for comparison. All the orifices had the same exit area of 1613 mm2. The Reynolds number, based on the equivalent diameter of the triangular orifices (calculated as ({{D}_{e}} = sqrt {4A{text{/}}pi } ), where A is the orifice exit area) or the diameter of the round orifice, was equal to (~left( {1.67 pm 0.08} right) times {{10}^{5}}). A Pitot-static tube was used to measure the mean streamwise velocities, and a hot-wire probe was used for all other measurements. The mean streamwise centerline velocity decays at the fastest rate in the near field of the 160° triangular jet. The Strouhal number, based upon the preferred mode frequency and initial momentum thickness, in all the jets tested has its highest value in the 160° triangular jet. Also, the inertial subrange in the one-dimensional energy spectra occurs closest to the exit plane in this jet compared to the other jets. The autocorrelation coefficients of the fluctuating streamwise velocities exhibit long tails in the 10° and 160° triangular jets, consistent with the nearly uniform initial mean streamwise velocity profiles in these jets.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147336128","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

Droplet Impact Physics of Ammonium Dinitramide (ADN)-Based Monopropellants on Solid Substrates of Varying Roughness 基于二硝酰胺铵（ADN）的单一推进剂在不同粗糙度固体基质上的液滴碰撞物理

IF 0.6 4区工程技术

Fluid Dynamics Pub Date : 2026-03-01 DOI: 10.1134/S0015462825602013

A. Paul, S. Sarkar, K. Raj, P. Kumar, P. R. L. Raj

{"title":"Droplet Impact Physics of Ammonium Dinitramide (ADN)-Based Monopropellants on Solid Substrates of Varying Roughness","authors":"A. Paul, S. Sarkar, K. Raj, P. Kumar, P. R. L. Raj","doi":"10.1134/S0015462825602013","DOIUrl":"10.1134/S0015462825602013","url":null,"abstract":"This study explores the impact dynamics and morphological evolution of ADN-based green liquid propellant droplets on flat, non-heated surfaces with systematically varied surface roughness Ra from 0.015 to 2.166 µm. Using high-speed imaging, the droplet interactions were captured across three Weber numbers (We = 46.29, 104.15, and 186.15), corresponding to the impact velocities of 1, 1.5, and 2 m/s for the 2 mm diameter droplets. The spreading behaviour was quantified through time-resolved measurements of the spreading ratio β, while morphological features, such as lamella expansion, rim formation, and contact line stability, were evaluated. Results reveal that surface roughness critically controls the maximum spreading, retraction rate, and energy dissipation. The maximum spreading ratio βmax was found to scale with the Weber number, with rapid retraction observed. A curve fitting analysis was performed for this scaling relationship, aligning well with classical inertial-capillary dynamics. Moderately rough surfaces (Ra = 0.2915 µm) enhanced spreading due to optimal capillary attachment, but beyond the roughness Ra = 0.318 µm, micro texture-induced damping suppressed further spreading, reduced β–We sensitivity, and halted retraction. Compared to conventional fluids, ADN droplets exhibited higher maximum spreading on smooth substrates and sharper saturation on rough ones.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147336129","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

Erosion Characteristics of a Novel Spherical Swivel in Air Drilling: Insights from Gas–Solid Two-Phase Flow Simulation 空气钻井中新型球形旋流器的侵蚀特性：来自气固两相流模拟的见解

IF 0.6 4区工程技术

Fluid Dynamics Pub Date : 2026-03-01 DOI: 10.1134/S0015462825603511

Y. Cao, B. Qi, H. Y. Zhang, P. L. Cao, G. Q. Cui

{"title":"Erosion Characteristics of a Novel Spherical Swivel in Air Drilling: Insights from Gas–Solid Two-Phase Flow Simulation","authors":"Y. Cao, B. Qi, H. Y. Zhang, P. L. Cao, G. Q. Cui","doi":"10.1134/S0015462825603511","DOIUrl":"10.1134/S0015462825603511","url":null,"abstract":"In air reverse circulation drilling using double-wall drill pipes, the elbow swivel is prone to failure and leakage under the high-speed impact of rock cuttings. To address these challenges, in this study a novel spherical swivel was proposed. A coupled CFD-DPM method was employed within Euler–Lagrange framework and Huser–Kvernvold erosion model to investigate the erosion behavior and the mechanism of rock cuttings in the spherical swivel. Simulation results reveal that, in contrast to the severe erosion of the traditional elbow swivel caused by repeated collisions of rock cuttings in local areas, the erosion in the spherical swivel is dominated by the initial impact of rock cuttings. Within the spherical chamber, rock cuttings are effectively dispersed without significant superposition of secondary impacts. The maximum erosion rate of the spherical swivel is approximately 42% lower than that of the conventional elbow swivel. An increase in the chamber diameter of the spherical swivel can further reduce erosion by enhancing particle kinetic energy dissipation and minimizing impact superposition, while the angle between the inlet and outlet pipes shows a negligible influence on the erosion characteristics. Furthermore, a higher drilling rate substantially intensifies erosion due to the increased generation of rock cuttings per unit time. The greater cuttings velocities correspond to the higher kinetic energy, and, consequently, more severe erosion. Given that the size of rock cuttings is inherently small, variations in their size have a limited effect on the erosion behavior. The findings provide crucial insights for improving the drilling efficiency and operational safety in air reverse-circulation drilling systems.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147336201","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

Unsupervised Particle Image Velocimetry Framework Based on Multi-Scale Inception Depthwise Convolution and Subpixel Upsampling 基于多尺度初始深度卷积和亚像素上采样的无监督粒子图像测速框架

IF 0.6 4区工程技术

Fluid Dynamics Pub Date : 2026-03-01 DOI: 10.1134/S0015462825601913

Z. Zhou, J. Ni, Y. Wang

引用次数: 0

Experimental Study on Bubble Motion Behavior in Ultrasonic Traveling Wave Fields 超声行波场中气泡运动特性的实验研究

IF 0.6 4区工程技术

Fluid Dynamics Pub Date : 2026-03-01 DOI: 10.1134/S0015462825603390

X. Zheng, H. Ni, M. J. Pang

引用次数: 0