Fluid Dynamics最新文献_第4页

Experimental Study on Mach Disk Characteristics of an Extremely Under-Expanded Hydrogen Jet with High Pressure Direct Injection 极欠膨胀高压直喷氢射流马赫盘特性实验研究

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-07-19 DOI: 10.1134/S0015462826604705

W. J. Ma, F. Ma, L. Y. Guo, C. T. Wang, Z. Z. Qin, X. Ma, F. L. Yang

{"title":"Experimental Study on Mach Disk Characteristics of an Extremely Under-Expanded Hydrogen Jet with High Pressure Direct Injection","authors":"W. J. Ma, F. Ma, L. Y. Guo, C. T. Wang, Z. Z. Qin, X. Ma, F. L. Yang","doi":"10.1134/S0015462826604705","DOIUrl":"10.1134/S0015462826604705","url":null,"abstract":"The high-pressure direct injection hydrogen internal combustion engines represent a significant technical path towards achieving zero-carbon power systems. However, current research lacks systematic experimental data and empirical models for the near-field Mach disk structure of high-pressure hydrogen jets. This study experimentally investigates the near-field Mach disk structure of the high-pressure hydrogen jets based on high-speed schlieren/shadow imaging technology. Firstly, the transient evolution laws of the Mach disk height and diameter are revealed. It is found that the Mach disk first appears approximately at 0.075 ms after injection and enters a quasi-steady state at around 0.25 ms. Secondly, based on the quasi-steady state data, empirical relationships between the dimensionless Mach disk height and diameter and the pressure ratio are established. Using the least squares fitting, empirical coefficients for the dimensionless Mach disk height and diameter are obtained as 0.4384 and 0.1442, respectively, with determination coefficients of 0.9977 and 0.989. By comparing with the empirical coefficients of classical air jets, the reasons for the lower empirical coefficients are attributed to the high-pressure real gas effect, the squeezing suppression by the high ambient pressure, and the flow loss at the outlet caused by the guide slot. The research results can provide a direct theoretical basis for CFD simulation of high-pressure direct injection hydrogen internal combustion engines.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 3","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148613345","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 the Design and Fluid-Structure Interaction of Ni–Ti Alloy Vascular Stent with Biomimetic Microstructure 仿生微结构镍钛合金血管支架设计及流固耦合分析

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-07-19 DOI: 10.1134/S0015462826604687

L. Yang, L. Yao, J. Q. Su, L. N. Sheng

{"title":"Analysis of the Design and Fluid-Structure Interaction of Ni–Ti Alloy Vascular Stent with Biomimetic Microstructure","authors":"L. Yang, L. Yao, J. Q. Su, L. N. Sheng","doi":"10.1134/S0015462826604687","DOIUrl":"10.1134/S0015462826604687","url":null,"abstract":"In this paper, the stent material is upgraded to Ni–Ti alloy based on the common metal stent, and the bionic microstructure was designed on the inner surface of Ni–Ti alloy stent. The surface microstructure could improve the blood flow characteristics in blood vessels, reduce the probability of intrastent restenosis, and increase the service life of vascular stents. Five kinds of shark-skin triangular vascular stents of different heights are discussed by using bionic drag reduction theory and fluid dynamics theory. It is found that surface microstructure at the height of 35 μm improved the blood flow characteristics best through a comparative analysis. Then, the fluid-structure interaction of the vascular stent with the surface microstructure of 35 μm and the vascular stent without surface microstructure are established to analyze the influence of surface microstructure on the blood flow rate and the pressure in the stent, as well as the changes caused by blood reaction on the blood vessel and stent. The results showed that surface microstructure can indeed improve the blood flow characteristics in the blood vessels, reduce the probability of in-stent Restenosis and increase the service life of the stent.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 3","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148613415","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

Mitigating Stall in Wind Turbines through Modified Leading-Edge Tubercle Airfoils 通过改进前缘结核翼型减轻风力涡轮机失速

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-07-19 DOI: 10.1134/S0015462825604462

I. Ali, T. Hussain, I. N. Unar, E. Gorgun

{"title":"Mitigating Stall in Wind Turbines through Modified Leading-Edge Tubercle Airfoils","authors":"I. Ali, T. Hussain, I. N. Unar, E. Gorgun","doi":"10.1134/S0015462825604462","DOIUrl":"10.1134/S0015462825604462","url":null,"abstract":"Tubercles at the leading edge (LE) of airfoils are used in maintaining the lift coefficient at the higher angle of attack (AoA) and delay stall. Previous research has documented the impact of varying the wavelength and amplitude of sinusoidal tubercles on the aerodynamic efficiency of various airfoil models, with a particular focus on changes at the leading edge. This study introduces a novel approach to tubercle design by analyzing the aerodynamic efficiency of a sinusoidal leading edge airfoil featuring a single, high-amplitude tubercle, offering a more realistic estimate of its effects. The research involves the development of three wing models – first, a baseline with a smooth leading edge; second, an airfoil with a tubercle labeled A3λ11; and third, an airfoil featuring a high-amplitude tubercle (A311λ11) on a sinusoidal leading edge. All airfoil models are developed using the NACA0021 airfoil profile and simulated at the 20° angle of attack. Large eddy simulations (LES) are conducted at a chord-based Reynolds number Rec = 1.2 × 105, and the results are validated against experimental data reported in the literature. Compared with the baseline airfoil, both tubercle airfoils show a substantial increase in the lift coefficient and a reduction in the drag coefficient. For the A3λ11 and A311λ11 airfoil models the lift coefficients increase by 34.8 and 12%, respectively. Moreover, reduction in the drag coefficient of about 10.3 and 23.6% are noticed for the A3λ11 and A311λ11 airfoil models, respectively. Additionally, the results reveal that the A311λ11 airfoil model exhibits a 14.9% reduction in the drag coefficient as compared to that of the sinusoidal A3λ11 airfoil model.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 3","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148613315","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 Investigation of Viscous Dominated Interface Evolution and Inertia Dominated Front Velocity in Two-Dimensional Miscible Lock-Exchange Flow 二维混相锁交换流中粘性主导界面演化和惯性主导前缘速度的分析研究

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-07-19 DOI: 10.1134/S0015462826604845

M. Yavari, A. Shahverdi, M. Bazargan

{"title":"Analytical Investigation of Viscous Dominated Interface Evolution and Inertia Dominated Front Velocity in Two-Dimensional Miscible Lock-Exchange Flow","authors":"M. Yavari, A. Shahverdi, M. Bazargan","doi":"10.1134/S0015462826604845","DOIUrl":"10.1134/S0015462826604845","url":null,"abstract":"The lock-exchange flow of two miscible fluids in horizontal and inclined rectangular channels is investigated to establish a unified description of interface evolution and front dynamics across flow regimes. In horizontal and weakly inclined channels, the flow is shown to be viscous-dominated and adequately described in a quasi-parallel formulation. In this regime, the temporal evolution of the interface is derived directly from the Navier–Stokes equations, providing a simple analytical framework for predicting the interface shape and the associated front velocity. As the channel inclination or the density contrast increase, the flow transitions to an inertia-dominated regime, in which front propagation is governed by the local pressure and momentum balances rather than the viscous stresses. An analytical criterion is proposed to identify the onset of inertia-dominated behavior. At higher inclinations or density contrasts, interfacial instabilities and mixing lead to deviations from simplified predictions that neglect mixing; in these cases, experimental observations are used to interpret variations in the front velocity. The analysis also clarifies how inertia-dominated flows adjust the bulk flow rate to accommodate front motion. Overall, this study provides a consistent framework linking viscous-dominated interface evolution and inertia-dominated front dynamics in rectangular channels, thereby extending previous two-dimensional descriptions and offering a physically grounded interpretation of experimental observations.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 3","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148613416","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

Investigation of the Influence of Dual Droplets on Fine Particulate Matter Capture Efficiency 双液滴对细颗粒物捕获效率影响的研究

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-07-19 DOI: 10.1134/S0015462826600148

Y. P. Qi, J. Li, H. Z. Zhao, P. Song, S. C. Wang

{"title":"Investigation of the Influence of Dual Droplets on Fine Particulate Matter Capture Efficiency","authors":"Y. P. Qi, J. Li, H. Z. Zhao, P. Song, S. C. Wang","doi":"10.1134/S0015462826600148","DOIUrl":"10.1134/S0015462826600148","url":null,"abstract":"Dual droplets are used as the research object to investigate the capture characteristics of droplet swarms on fine particulate matter, and a simulation method is employed to explore the influence rules of the dimensionless spacing and the Reynolds number on the capture efficiency. The results show that the capture effect of dual droplets is better than that of a single droplet (up to twice that of a single droplet). At the same Reynolds number, the capture efficiency first increases and then decreases with increase in dimensionless spacing. At the same spacing, the capture efficiency increases with the rise in the Reynolds number, and the capture efficiency growth rate slows down when the Reynolds number reaches 500. The optimal operating conditions for capturing fine particulate matter are the dimensionless spacing 3.5 and the Reynolds number 500. The mechanism through which the front-end velocity of the droplet affects the capture efficiency is clarified, and it is revealed that excessively large dimensionless spacing will expand the “escape space” of particulate matter, while overly small spacing will reduce the “combined capture range.” The findings of this study can provide a theoretical support for droplet swarm capture systems and have practical guiding significance for improving the dust removal efficiency of fine particulate matter.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 3","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148613414","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

Reynolds Analogy Factor in the Compressible Turbulent Boundary Layer on a Cooled Wall 冷却壁面上可压缩湍流边界层的雷诺数类比因子

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-07-19 DOI: 10.1134/S0015462826605371

V. G. Lushchik, A. I. Reshmin, A. D. Chicherina

引用次数: 0

Quantitative Analysis of the Effects of Pre-Flush Stage and Near-Wellbore Fracture Network on Wormhole Morphology in Fractured Carbonate Reservoirs 裂缝性碳酸盐岩储层预冲段及近井裂缝网络对虫孔形态影响的定量分析

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-07-19 DOI: 10.1134/S001546282660029X

K. Liu, L. C. Qu, X. Kang, S. Y. Wang, Z. H. Hu, S. Y. Liang

{"title":"Quantitative Analysis of the Effects of Pre-Flush Stage and Near-Wellbore Fracture Network on Wormhole Morphology in Fractured Carbonate Reservoirs","authors":"K. Liu, L. C. Qu, X. Kang, S. Y. Wang, Z. H. Hu, S. Y. Liang","doi":"10.1134/S001546282660029X","DOIUrl":"10.1134/S001546282660029X","url":null,"abstract":"The displacement of oil phase in pores near the wellbore during the pre-flush stage prior to acidizing operations significantly affects the acidizing effect, particularly, in fractured carbonate reservoirs. In this study, a numerical simulation program for oil–water two-phase flow in fractured carbonate reservoirs covering the entire pre-flush-acidizing process was developed to investigate this problem. The results indicate that the pre-flush stage can effectively enhance the transport capacity of hydrogen ion H+ within pores and improve the acidizing effect; specifically, the higher the volume of injected fluid, the more significant the improvement in the acidizing effect. However, the extent to which excessive fluid injection further enhances the acidizing effect gradually diminishes, and there exists an optimal injection volume, which is determined to be 1.0 pore volume (PV) in this study. The fractures disturb the development trend of wormholes, and this disturbance becomes more pronounced as the fracture density increases. The shielding effect induced by the fractures weakens the efficacy of pre-flushing and elevates the optimal injection volume, which increases from 1.0 to 1.5 pore volume in this study. Overall, the pre-flush stage can enhance the acidizing effect under high acid injection rates by reducing the acid-rock reaction rate.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 3","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148613335","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

Modeling of an Intravascular Stent Using the Navier Boundary Condition with Variable Slip Length: 2D Analysis of Hemodynamic Characteristics 基于可变滑移长度Navier边界条件的血管内支架建模：血流动力学特性的二维分析

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-07-19 DOI: 10.1134/S0015462826605504

D. Tikhvinskii, A. Chupakhin, D. Parshin

{"title":"Modeling of an Intravascular Stent Using the Navier Boundary Condition with Variable Slip Length: 2D Analysis of Hemodynamic Characteristics","authors":"D. Tikhvinskii, A. Chupakhin, D. Parshin","doi":"10.1134/S0015462826605504","DOIUrl":"10.1134/S0015462826605504","url":null,"abstract":"This paper presents a new approach to modeling an intravascular stent in a two-dimensional problem formulation. This approach uses a variable-slip Navier boundary condition, simulating the periodic structure of the stent (wire thickness and number of turns). Unlike explicit modeling of stent geometry or a porous-medium approach, the proposed method reduces computational costs and takes into account major geometric parameters. The steady-state flow of a viscous incompressible fluid in a flat channel is supplemented by an analytical description of planar Hill vortex analogs in sinusoidal valleys. Numerical experiments in ANSYS are used to study the influence of wire thickness (120–400 μm) and the number of peaks (10, 30, 50) on the change in flow velocity, wall shear stress (WSS), and the specific dissipation function. It was found that increasing the wire thickness leads to an increase in velocity (up to 24%) and a decrease in WSS (up to 13%), with a weak dependence on the number of peaks in steady-state mode. In quasi-steady (pulsating) flow, the influence of stent periodicity becomes more pronounced. The value of the dissipative function decreases with increasing wire thickness (up to 25%), indicating a reduction in viscous losses due to sliding. The proposed method may be useful for rapid screening assessment of the hemodynamic effects of stents during the preclinical design stage.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 3","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0015462826605504.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148613239","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

Drag Reduction in Turbulent Channel Flow with Composite Control Based on the Lorentz Force and Sinusoidal Grooves 基于洛伦兹力和正弦沟槽复合控制的湍流通道减阻

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-07-19 DOI: 10.1134/S0015462826604602

D. W. Jiang, S. Luo, C. Xu, X. X. Liu, J. X. Shi, W. G. Yao, Y. N. Li

{"title":"Drag Reduction in Turbulent Channel Flow with Composite Control Based on the Lorentz Force and Sinusoidal Grooves","authors":"D. W. Jiang, S. Luo, C. Xu, X. X. Liu, J. X. Shi, W. G. Yao, Y. N. Li","doi":"10.1134/S0015462826604602","DOIUrl":"10.1134/S0015462826604602","url":null,"abstract":"Fully developed turbulent channel flow at Re = 4000 controlled by the composite approach based on the Lorentz force and sinusoidal grooves is numerically studied. The expanded Fourier–Chebyshev spectral method with coordinate transformation is applied together with the direct numerical simulation (DNS) method to solve the turbulent flow. In-depth relations among the characteristic structures in the flow field, the mean Reynolds shear stress, and the effect of drag reduction are discussed and compared with those in the flow field controlled by the Lorentz force only. The results show that the flow field controlled by the composite approach affords a drag reduction rate of 47%, while that controlled by the only Lorentz force approach affords a rate of 34.6%. For the composite approach, an additional flow with two velocity components along the spanwise and normal directions, respectively, is induced. The distributions of the two velocity components exhibit periodicity with alternating positive and negative values, thereby generating array-based quasi-streamwise vortices. Such vortices are capable of altering streak structures, suppressing bursting events, reducing the magnitude of the mean Reynolds shear stress, and modulating the mean velocity profiles in the near-wall region—ultimately yielding the drag reduction effect. Furthermore, the organized quasi-streamwise vortices induced via the composite approach demonstrate greater stability compared to those generate by the only Lorentz force method. Therefore, the composite approach is advantageous in terms of the drag reduction effect and efficiency.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 3","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148613317","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

Regular and Mach Reflection of Hydraulic Jumps in Film Flows on Ordinary and Superhydrophobic Surfaces 普通和超疏水表面上膜流中水跃的规则反射和马赫反射

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-07-19 DOI: 10.1134/S0015462826605188

A. I. Ageev, A. N. Osiptsov

{"title":"Regular and Mach Reflection of Hydraulic Jumps in Film Flows on Ordinary and Superhydrophobic Surfaces","authors":"A. I. Ageev, A. N. Osiptsov","doi":"10.1134/S0015462826605188","DOIUrl":"10.1134/S0015462826605188","url":null,"abstract":"<div>Within the framework of an averaged description of viscous film flows in the gravity field, we analyze the relations on oblique hydraulic jumps and the limits of existence of the regimes of regular and Mach reflection of intersecting hydraulic jumps on a horizontal ordinary or superhydrophobic surface. In contrast to previous studies, we use the modified relations on hydraulic jumps (analogues of Rankine–Hugoniot relations on strong discontinuities) obtained in the previous publication of the authors. These modified relations contain additional terms which (in a general case) take into account a jump in the total normal flux of the momentum (based on the averaged velocity) and a difference in the tangential velocities of the fluid in the film on the oblique hydraulic jump on a superhydrophobic surface. Examples of velocity hodograph polars are calculated for an oblique hydraulic jump and the effect of the velocity slip on the position of the oblique hydraulic jump in the flow over a wedge-type obstacle on the film edge is investigated. The limits of the regimes of regular and Mach reflection of crossing oblique hydraulic jumps in liquid films on ordinary and superhydrophobic surfaces, calculated using standard and modified relations on the jump, are compared. The difference in the parameters behind the reflected jumps for different film flow models is estimated.</div>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 3","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0015462826605188.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148613344","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