Fluid Dynamics Research最新文献_第4页

Sedimentation of particles with various shapes and orientations in a closed channel using smoothed particle hydrodynamics 利用光滑粒子流体动力学研究不同形状和方向的粒子在封闭通道中的沉积

IF 1.5 4区工程技术

Fluid Dynamics Research Pub Date : 2023-07-03 DOI: 10.1088/1873-7005/ace37b

Lizhong Huang, Chun Shao, Ruijin Wang, Jiayou Du, Zefei Zhu

{"title":"Sedimentation of particles with various shapes and orientations in a closed channel using smoothed particle hydrodynamics","authors":"Lizhong Huang, Chun Shao, Ruijin Wang, Jiayou Du, Zefei Zhu","doi":"10.1088/1873-7005/ace37b","DOIUrl":"https://doi.org/10.1088/1873-7005/ace37b","url":null,"abstract":"The sedimentation of particles with various shapes and orientations in a closed channel using smoothed particle hydrodynamics is investigated in this paper. The continuity and momentum equations of both fluid and solid are discretized using kernel approximation in the Lagrangian frame. The sedimentation behavior of different general shapes, including circle, pentagon, square, ellipse, rectangle, and triangle, at various initial orientations in the suspending fluid is simulated. The stable equilibrium orientation (SEO) of these shapes is examined, excluding the circle which serves as a validation case. Specifically, the major axis of the ellipse and rectangle tends to align horizontally, whereas the orientations of the pentagon and square seem to be random due to the lack of a major axis and the finite channel height. The settling behavior of the three types of triangles is also discussed, and the von Mises stress of these shapes during their settling is presented. This study offers valuable insights into fluid-particle interactions, specifically regarding the SEO and internal stress of settling particles with varying shapes and orientations.","PeriodicalId":56311,"journal":{"name":"Fluid Dynamics Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43273477","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

Three-dimensional simulations of fluid flows in oscillating lid-driven cavities using lattice Boltzmann method 用晶格玻尔兹曼方法模拟振荡盖驱动腔体中的流体流动

IF 1.5 4区工程技术

Fluid Dynamics Research Pub Date : 2023-07-03 DOI: 10.1088/1873-7005/ace37c

S. Rajakumar, D. A. Perumal, A. Yadav

引用次数: 0

Exploration of rheological behavior of an Ellis fluid on the onset of thermosolutal porous convection 热溶质多孔对流开始时埃利斯流体流变行为的探索

IF 1.5 4区工程技术

Fluid Dynamics Research Pub Date : 2023-07-03 DOI: 10.1088/1873-7005/ace37a

Y. Vinod, I. Shivakumara, K. R. Raghunatha

{"title":"Exploration of rheological behavior of an Ellis fluid on the onset of thermosolutal porous convection","authors":"Y. Vinod, I. Shivakumara, K. R. Raghunatha","doi":"10.1088/1873-7005/ace37a","DOIUrl":"https://doi.org/10.1088/1873-7005/ace37a","url":null,"abstract":"The initiation of thermosolutal convective instability is investigated in a horizontal porous layer saturated by a shear-thinning fluid following Ellis’ rheology. The porous layer is heated as well as salted from below and a basic horizontal throughflow prompted by the prescribed pressure gradient is considered. The linear stability analysis is performed using normal mode analysis and the threshold conditions for the onset of convection are obtained in a closed form. The imposed horizontal pressure gradient and the solute concentration gradient reinforce together in resulting the onset of convection through oscillatory motions. The transverse rolls are the most unstable which are found to be both travelling and non-travelling in the reference frame comoving with the basic throughflow. The effect of increasing the Ellis power-law index and the solute Darcy-Rayleigh number is to stabilise, while an increase in the Darcy-Ellis number is to destabilise the base flow. The pressure and temperature/solute concentration lines are presented at the critical state. The results delineated under the limiting cases are shown to be in agreement with those published previously.","PeriodicalId":56311,"journal":{"name":"Fluid Dynamics Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44970926","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: 1

Margination of platelet-sized particles in red blood cell suspensions flowing through a Y-shaped confluence microchannel 红细胞悬浮液中血小板大小的颗粒通过y形合流微通道的边缘

IF 1.5 4区工程技术

Fluid Dynamics Research Pub Date : 2023-06-01 DOI: 10.1088/1873-7005/acdf7c

Akira Noguchi, Yuki Tange, T. Itano, M. Sugihara-Seki

{"title":"Margination of platelet-sized particles in red blood cell suspensions flowing through a Y-shaped confluence microchannel","authors":"Akira Noguchi, Yuki Tange, T. Itano, M. Sugihara-Seki","doi":"10.1088/1873-7005/acdf7c","DOIUrl":"https://doi.org/10.1088/1873-7005/acdf7c","url":null,"abstract":"In blood flow through microvessels, platelets are known to be distributed in high concentrations near the vessel wall, termed ‘margination’ or ‘near-wall excess’. At the confluence of two vessels, this preferential distribution of platelets is thought to be compromised and reconstituted in the downstream main vessel. The present study aimed to investigate the distance of this margination reconstruction from the confluence by in vitro experiments using platelet-sized fluorescent particles as a platelet surrogate and a Y-shaped confluence microchannel with rectangular cross sections. Fluorescence microscopy was performed using a confocal laser scanning microscope system to measure the distribution of particles in the red blood cell suspension flow. Immediately after confluence, particles were highly concentrated along a narrow band in the middle of the channel width, where particles located near the inner wall of the daughter channels flowed in. This dense band of particles faded downstream and disappeared less than 5 mm from the confluence. This margination distance is comparable to or smaller than the margination development distance in straight channels, but much smaller than that after bifurcation.","PeriodicalId":56311,"journal":{"name":"Fluid Dynamics Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46968591","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

The dynamic behavior of a droplet flows through a constricted splitting channel: a lattice Boltzmann study 液滴在狭窄的分裂通道中流动的动态行为:晶格玻尔兹曼研究

IF 1.5 4区工程技术

Fluid Dynamics Research Pub Date : 2023-06-01 DOI: 10.1088/1873-7005/acdc4e

Dapeng Deng, Huifang Dong, Yusheng Liang

{"title":"The dynamic behavior of a droplet flows through a constricted splitting channel: a lattice Boltzmann study","authors":"Dapeng Deng, Huifang Dong, Yusheng Liang","doi":"10.1088/1873-7005/acdc4e","DOIUrl":"https://doi.org/10.1088/1873-7005/acdc4e","url":null,"abstract":"In this paper, a lattice Boltzmann method is used to simulate the dynamic behavior of a droplet flows through a constricted channel, where an obstacle is placed in the center of the constricted channel to split the droplet. The method is first used to simulate the effect of the capillary number Ca on the volume of the divided daughter droplets. Results show that the volume difference between the daughter droplets above and below the obstacle increases as Ca increases. We also find that reducing the capillary number is conducive to the droplet splitting into two daughter droplets with similar volume. The method is then used to simulate the influence of the viscosity ratio λ on the droplet flows through a constricted channel. As λ increases, the volume difference between the daughter droplets above and below the obstacle decreases. Finally, the influence of the confinement ratio Wc on the evolution of the droplet morphology is investigated. With increase in Wc , the volume difference between the daughter droplets above and below the obstacle increases. When Wc⩾1 , the droplet does not break up and completely enters the bottom channel. Comparing with the converging-diverging and ratchet channels, the constricted splitting channel is more conductive to the breakup of the droplet neck.","PeriodicalId":56311,"journal":{"name":"Fluid Dynamics Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43478093","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

Computationally effective estimation of supersonic flow field around airfoils using sparse convolutional neural network 基于稀疏卷积神经网络的超音速翼型流场计算有效估计

IF 1.5 4区工程技术

Fluid Dynamics Research Pub Date : 2023-05-22 DOI: 10.1088/1873-7005/acd7a0

Ming-yu Wu, Jiang-Zhou Peng, Zhi-ming Qiu, Zhi-Hua Chen, Yu-Bai Li, Wei-Tao Wu

{"title":"Computationally effective estimation of supersonic flow field around airfoils using sparse convolutional neural network","authors":"Ming-yu Wu, Jiang-Zhou Peng, Zhi-ming Qiu, Zhi-Hua Chen, Yu-Bai Li, Wei-Tao Wu","doi":"10.1088/1873-7005/acd7a0","DOIUrl":"https://doi.org/10.1088/1873-7005/acd7a0","url":null,"abstract":"This work proposes an innovative approach for supersonic flow field modeling around airfoils based on sparse convolutional neural networks (SCNNs) and Bézier generative adversarial network (GAN), where (1) the SCNN model is built to end-to-end predict supersonic compressible physical flow fields around airfoils from spatially-sparse geometries and (2) the trained Bézier-GAN is utilized to generate plenty of smooth airfoils as well as the latent codes representing airfoils. The spatially-sparse positions of airfoil geometry are represented using signed distance function (SDF). Particularly, the latent codes are merged with the SDF matrix and the Mach number to form the input of the SCNN model, effectively making the SCNN model possess more robust geometric adaptability to different flow conditions. The most significant contribution compared to the regular convolutional neural network is that SCNN introduces sparse convolutional operations to process spatially-sparse input matrix, specifically, which only focuses on the local area with flow information when performing convolution, eventually saving memory usage and improving the network’s attention on the flow area. Further, the testing results show that the SCNN model can more accurately predict supersonic flow fields with a mean absolute error lower than 5% and save 40% of graphics processing unit memory. These results indicate that the proposed SCNN model can capture the shock wave features of supersonic flow fields and improve learning efficiency and computing efficiency.","PeriodicalId":56311,"journal":{"name":"Fluid Dynamics Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44949674","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

Small amplitude dust acoustic solitary waves in a magnetized dusty plasma with nonthermal distribution for both electrons and ions 电子和离子非热分布的磁化尘埃等离子体中的小振幅尘埃声孤立波

IF 1.5 4区工程技术

Fluid Dynamics Research Pub Date : 2023-05-16 DOI: 10.1088/1873-7005/acd5fb

R. Kian, M. Mahdieh

{"title":"Small amplitude dust acoustic solitary waves in a magnetized dusty plasma with nonthermal distribution for both electrons and ions","authors":"R. Kian, M. Mahdieh","doi":"10.1088/1873-7005/acd5fb","DOIUrl":"https://doi.org/10.1088/1873-7005/acd5fb","url":null,"abstract":"The propagation of dust acoustic solitary waves (DASWs) has been investigated in a magnetized dusty plasma consisting of negatively charged dust particles, nonthermal ions and nonthermal electrons. Using reductive perturbation method, the Korteweg-de-Vries (K-dV) equation is derived. It is found that the basic structures (such as polarity, amplitude, width) of DASWs are influenced by nonthermal ions and nonthermal electrons. The results show that both compressive and rarefactive DASWs exist in such dusty plasma. It is observed that by increasing the nonthermality parameter of ions and electrons, the nonlinear wave phase velocity increases. Furthermore, nonthermal distributed ions have more effect on the nonlinear wave phase velocity of the DASWs than nonthermal distributed electrons. The dependence of the angle that the external magnetic field makes with the propagation direction of wave on the amplitude and width of DASWs has been also investigated. It was concluded that this angle strongly affects the DASWs. Finally, the effect of the magnetic field appears only in the width and not in the amplitude of the DASWs. The findings of this study can be helpful in understanding the structures of DASWs in the dusty plasma in which both nonthermal ions and nonthermal electrons exist. Such structures can be found in different regions of space and astrophysics mediums such as the upper ionosphere and Saturn’s E-ring.","PeriodicalId":56311,"journal":{"name":"Fluid Dynamics Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48112347","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

Continuous motion of an electrically actuated water droplet over a PDMS-coated surface 电驱动水滴在pdms涂层表面上的连续运动

IF 1.5 4区工程技术

Fluid Dynamics Research Pub Date : 2023-04-30 DOI: 10.1088/1873-7005/acf47e

S. Upadhyay, Krishnamurthy Muralidhar

{"title":"Continuous motion of an electrically actuated water droplet over a PDMS-coated surface","authors":"S. Upadhyay, Krishnamurthy Muralidhar","doi":"10.1088/1873-7005/acf47e","DOIUrl":"https://doi.org/10.1088/1873-7005/acf47e","url":null,"abstract":"Electrically actuated linear motion of a water droplet over PDMS-coated single active electrode is analyzed from detailed experiments and modeling. In an experiment, continuous motion of the droplet is achieved when it is located over an active electrode with a horizontal ground wire placed just above in an open-electrowetting-on-dielectric configuration. Using a CCD camera, the instantaneous centroid position of the droplet is determined and its velocity is inferred by numerical differentiation. The edge-detected image is also used to determine the advancing and receding contact angles of the moving drop relative to the substrate. Motion of 2, 6, and 10 µl water droplets for voltages in the range of 170–270 V DC is examined to investigate the effect of drop volume and voltage on drop deformation and velocity. The motion of the droplet is initiated by Young-Lippmann spreading at the three-phase contact line, followed by a nonuniform electric force field distributed between the active electrode and the ground wire localized at the droplet-air interface. Simulations carried out using COMSOL© Multiphysics with full coupling between the electric field and hydrodynamics are in conformity with experiments. A contact angle model with pinning and friction leads to close agreement between simulations and drop motion over a bare PDMS layer, particularly in terms of the relevant timescales. When contact line friction is neglected, the fully coupled numerical solution shows a good match with experimentally determined drop movement over a silicone oil-coated PDMS layer. Over both surfaces, continuous motion of the water droplet is seen to be achieved in three stages, namely, initial spreading, acceleration, and attainment of constant speed.","PeriodicalId":56311,"journal":{"name":"Fluid Dynamics Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44135416","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

New insights into the extended and generalised PTT constitutive differential equations: weak flows 扩展和广义PTT本构微分方程的新见解：弱流

IF 1.5 4区工程技术

Fluid Dynamics Research Pub Date : 2023-04-27 DOI: 10.1088/1873-7005/acd0d4

L. L. Ferrás, A. Afonso

引用次数: 0

Phase transition between pure modes A and B in a circular cylinder’s wake. Part I: analysis of fluid forces 圆柱尾迹中纯模A和纯模B之间的相变。第一部分:流体力的分析

IF 1.5 4区工程技术

Fluid Dynamics Research Pub Date : 2023-04-25 DOI: 10.1088/1873-7005/acd025

L. M. Lin

引用次数: 1