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Structure of Swirling Flow in the Channel Branching Area at Moderate Reynolds Numbers
IF 1 4区 工程技术
Fluid Dynamics Pub Date : 2024-11-12 DOI: 10.1134/S0015462824602663
V. M. Molochnikov, I. V. Nikiforov, N. D. Pashkova
{"title":"Structure of Swirling Flow in the Channel Branching Area at Moderate Reynolds Numbers","authors":"V. M. Molochnikov,&nbsp;I. V. Nikiforov,&nbsp;N. D. Pashkova","doi":"10.1134/S0015462824602663","DOIUrl":"10.1134/S0015462824602663","url":null,"abstract":"<p>The results of experimental studies of steady-state swirling flow in the area of channel branching, that imitates the proximal end-to-side anastomosis of the human femoral artery, are given. The experiments were carried out at a Reynolds number of 1460. This corresponds to the range of physiological values when estimating by the maximum blood flow rate in the artery during the period of cardiac contractions. For both branches, an equal ratio of the flow rates was maintained. At the inlet to the branching area, the degree of flow swirl was equal to 0.125. Using the SIV (smoke image velocimetry) technique, flow was visualized and the instantaneous vector flow velocity fields of each branch were measured. The main patterns of the influence of swirl on the vortex structure of flow in the main artery below the branching area and in the shunt have been revealed. The possibility of using flow swirl to create more favorable hemodynamic conditions in the anastomotic area is being considered. A particular attention is paid to the appearance of signs of local flow turbulization in the presence and absence of swirl.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 5","pages":"1038 - 1055"},"PeriodicalIF":1.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108619","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
Instantaneous and Average Structure of a Supersonic Underexpanded Jet
IF 1 4区 工程技术
Fluid Dynamics Pub Date : 2024-11-12 DOI: 10.1134/S0015462824603012
V. I. Zapryagaev, I. N. Kavun, N. P. Kiselev, A. N. Kudryavtsev, A. A. Pivovarov, D. V. Khotyanovsky
{"title":"Instantaneous and Average Structure of a Supersonic Underexpanded Jet","authors":"V. I. Zapryagaev,&nbsp;I. N. Kavun,&nbsp;N. P. Kiselev,&nbsp;A. N. Kudryavtsev,&nbsp;A. A. Pivovarov,&nbsp;D. V. Khotyanovsky","doi":"10.1134/S0015462824603012","DOIUrl":"10.1134/S0015462824603012","url":null,"abstract":"<p>The instantaneous and average structure of a supersonic underexpanded jet is studied numerically and experimentally. The photos obtained in experiments with different exposure times and the Pitot pressure measurements are compared with the results of the numerical simulation performed using an implicit large-eddy method. We note that the jet flow instability, disturbance growth, and transition to turbulence lead to the situation, in which the instantaneous flow structure can be considerably different from the average structure. The flow pattern observable in the calculations is in good agreement with that presented in the experimental photos obtained with short exposure times. Both calculated and experimental data indicate that an important role in the jet flow dynamics is played by large-scale vortex structures that exist against the background of small-scale turbulence. The calculated and experimental Pitot pressure distributions are similar with each other, up to a certain distance from the nozzle exit section. Further downstream, the experimental and calculated Pitot pressures start to increase rapidly but the calculations predict the onset of this growth at a greater distance from the nozzle than it is observable in the experiments.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 5","pages":"1108 - 1116"},"PeriodicalIF":1.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108661","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 Solution for Transient Two-Dimensional Filtration nearby a Fracture of Finite Conductivity
IF 1 4区 工程技术
Fluid Dynamics Pub Date : 2024-11-12 DOI: 10.1134/S0015462824602249
I. K. Reznikov, D. A. Chuprakov
{"title":"Analytical Solution for Transient Two-Dimensional Filtration nearby a Fracture of Finite Conductivity","authors":"I. K. Reznikov,&nbsp;D. A. Chuprakov","doi":"10.1134/S0015462824602249","DOIUrl":"10.1134/S0015462824602249","url":null,"abstract":"<p>The problem of 2D filtration flow in the neighborhood of a producing vertical fracture of limited size and finite conductivity is revisited. New asymptotic solutions specific of 2D inflows to a fracture at early times with pseudo-1D inflows, and at large times with pseudo-radial inflows, are obtained. In general, the problem does not allow for an exact analytical solution to be obtained for any time and any fracture conductivity, even using the Laplace transform. In the limiting cases, the equations are simplified and can be solved either exactly or approximately. The vertex solutions are then interpolated to construct an approximate solution for the profiles of pressure, flowrate and inflow along a fracture at any time and any fracture conductivity. The derived general solution is compared with the numerical solver and analytical solutions, previously obtained for limiting cases of infinite conductivity, steady and pseudo-steady-state flow regimes. The obtained approximation makes it possible to estimate the accurate solution of a fluid filtration problem much faster than numerical methods, while maintaining the accuracy sufficient for field operations. This makes the results of this work to apply to extensive multivariate simulations of fractured well production and inverse problems, such as the problem of optimization and interpretation of field data.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 5","pages":"1168 - 1192"},"PeriodicalIF":1.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108573","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
Specific Features of the Flow in the Shock Layer near a Semicone on a Flat Plate
IF 1 4区 工程技术
Fluid Dynamics Pub Date : 2024-11-12 DOI: 10.1134/S0015462824603383
M. A. Zubin, F. A. Maksimov
{"title":"Specific Features of the Flow in the Shock Layer near a Semicone on a Flat Plate","authors":"M. A. Zubin,&nbsp;F. A. Maksimov","doi":"10.1134/S0015462824603383","DOIUrl":"10.1134/S0015462824603383","url":null,"abstract":"<p>We present the results of experimental and numerical investigations of the structure of the supersonic M = 3 flow past an arrangement of a semicone on a flat plate, where the cone vertex coincides with the supersonic leading edge of the plate. Using a specially developed optical method for visualizing supersonic conical flows it is established that in the flow past the arrangement at zero or nonzero angle of attack the separation region arising on interaction of either the conical bow shock or the inner shock wave with the plate boundary layer is situated totally on the plate. The appearance of additional singular lines on the semicone surface and vortex structures of inviscid origin in the shock layer is due to the occurrence of contact discontinuities proceeding from the triple points of either the λ-configuration of shock waves accompanying the separation region on the plate or the bow shock wave arising in the flow past the arrangement with or without an angle of attack. Numerical codes for calculating the flow in the conical approximation are developed basing on the viscous and inviscid gas models. The comparison of the calculated results with experimental data shows their satisfactory agreement and possible usage domains of any of these approaches.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 5","pages":"1117 - 1128"},"PeriodicalIF":1.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108576","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
Motion of an Elastic Drop through an Orifice in a Thin Plate
IF 1 4区 工程技术
Fluid Dynamics Pub Date : 2024-11-12 DOI: 10.1134/S001546282460336X
A. O. Rudenko, A. N. Rozhkov
{"title":"Motion of an Elastic Drop through an Orifice in a Thin Plate","authors":"A. O. Rudenko,&nbsp;A. N. Rozhkov","doi":"10.1134/S001546282460336X","DOIUrl":"10.1134/S001546282460336X","url":null,"abstract":"<p>Impingement of drops of water and polymer solutions on a thin plate with a solitary round orifice is studied. The drop diameter before the impingement <i>d</i><sub><i>i</i></sub> coincides with that of the orifice <i>d</i><sub><i>t</i></sub> and is equal to 3 mm. The drops fell from heights of 5, 10, and 20 mm, their velocities before the impingement amounting to 0.31, 0.44, and 0.63 m/s. The drops flew through the orifice touching slightly its edges. High-speed photography was used to fix different stages of the collision between a drop and the obstacle. It is found that a considerable deceleration of the jet by the orifice can be observable for the impingement parameters considered, down to the complete stopping of the drop flight. The mechanisms of the observable phenomena and the effect of different factors are discussed.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 5","pages":"1088 - 1098"},"PeriodicalIF":1.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108660","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
Testing of 2D Differential RANS Models by the Example of Heating the Surface of a Sharp Plate in Supersonic Flow
IF 1 4区 工程技术
Fluid Dynamics Pub Date : 2024-11-12 DOI: 10.1134/S0015462824604042
S. T. Surzhikov
{"title":"Testing of 2D Differential RANS Models by the Example of Heating the Surface of a Sharp Plate in Supersonic Flow","authors":"S. T. Surzhikov","doi":"10.1134/S0015462824604042","DOIUrl":"10.1134/S0015462824604042","url":null,"abstract":"<div><p>The Coakley “<i>q–</i>ω” and Chien “<i>k–</i>ε” low-Reynolds differential models are used together with the two-dimensional Reynolds-averaged Navier–Stokes (RANS) equations to interpret experimental data on heating and friction on the surface of a sharp plate in the turbulent boundary layer. The problems of choosing the boundary of the turbulent boundary layer and the specifics of the numerical integration of the RANS-model equations at a vanishingly low level of turbulent pulsations in the free-stream gas flow are analyzed.</p></div>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 5","pages":"1193 - 1239"},"PeriodicalIF":1.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108572","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
Distinctive Features of Using the Propulsor of the Underwater Sail Type and the Direct-Flow Wave Propulsor on a Semisubmerged Catamaran
IF 1 4区 工程技术
Fluid Dynamics Pub Date : 2024-11-12 DOI: 10.1134/S0015462824603309
E. A. Arkhangel’skii, A. V. Boiko, V. V. Prokof’ev
{"title":"Distinctive Features of Using the Propulsor of the Underwater Sail Type and the Direct-Flow Wave Propulsor on a Semisubmerged Catamaran","authors":"E. A. Arkhangel’skii,&nbsp;A. V. Boiko,&nbsp;V. V. Prokof’ev","doi":"10.1134/S0015462824603309","DOIUrl":"10.1134/S0015462824603309","url":null,"abstract":"<p>We present the results of experimental investigations of the efficiency of the direct flow wave propulsor and the propulsor of the underwater sail type on the models of semisubmerged catamaran boat with a small area of the section along the waterline. The effects observable in the case of the propulsor of the underwater sail type are qualitatively the same as for the previously studied swinging wing, namely, the greatest efficiency is observable, when the propulsor is situated near the free surface, while its efficiency is rapidly reduced with propulsor immersion. The propulsor efficiency varies only slightly with ship hull immersion, whereas the working frequencies are considerably reduced as compared with those of floating structures. In this case, the working frequencies vary in proportion to the model boat scale. Comprehensive studies of the direct-flow wave propulsor efficiency were performed, an inclined flat plate being fixed at the hulls of a semisubmerged ship as a working element. The optimal parameters of the propulsor were noted, when it efficiently operates on the waves with the greatest steepness (storm waves). Experiments showed that the efficiency of the wave propulsors of the swinging wing or underwater sail types in their operation ranges is somewhat higher than that of the direct-flow propulsor. However, under the rough water conditions the direct-flow propulsor has its own advantages, since precisely in this case it demonstrates its greatest efficiency, while the other versions considered are efficacious in the wavelength range dependent on the ship length and, generally speaking, do not coincide with the storm wave length.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 5","pages":"1017 - 1027"},"PeriodicalIF":1.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108621","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 the Flow around a Delta Wing Partially Made of a Permeable Material 模拟部分由渗透性材料制成的三角翼周围的水流
IF 1 4区 工程技术
Fluid Dynamics Pub Date : 2024-11-07 DOI: 10.1134/S0015462824602778
A. E. Lutsky, A. V. Severin
{"title":"Modeling the Flow around a Delta Wing Partially Made of a Permeable Material","authors":"A. E. Lutsky,&nbsp;A. V. Severin","doi":"10.1134/S0015462824602778","DOIUrl":"10.1134/S0015462824602778","url":null,"abstract":"<p>Mathematical modeling of a supersonic gas flow around a delta wing is carried out for M = 2. A wing made of a conventional solid material is compared to a wing whose leading edge is made of a porous material with a porosity coefficient of 0.6. The influence of a permeable edge on the flow structure and thermal regime is studied.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 4","pages":"1004 - 1015"},"PeriodicalIF":1.0,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595506","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
Distinctive Features of Propagation of a Turbulent Pulsed Gas-Droplet Eddy Cloud 湍流脉冲气体-液滴涡流云传播的显著特征
IF 1 4区 工程技术
Fluid Dynamics Pub Date : 2024-11-07 DOI: 10.1134/S0015462824602870
M. A. Pakhomov, V. P. Terekhov
{"title":"Distinctive Features of Propagation of a Turbulent Pulsed Gas-Droplet Eddy Cloud","authors":"M. A. Pakhomov,&nbsp;V. P. Terekhov","doi":"10.1134/S0015462824602870","DOIUrl":"10.1134/S0015462824602870","url":null,"abstract":"<p>We present the results of the numerical modeling of the formation and motion of a blown solitary pulsed turbulent gas-droplet jet under the conditions approximately corresponding to human cough. The calculations are performed for the pulse duration <i>t</i> = 0.6 s and the greatest velocity of the gas phase of 20 m/s at the mass fraction of droplets <i>M</i><sub><i>L</i>1</sub> = 1%. The drop phase in the exit section is monodisperse, while the initial dimension of particles in the calculations varied in the range <i>D</i><sub>1</sub> = 5‒30 μm. Two zones of elevated vorticity are formed within the cloud in the initial period of motion. They are situated in the mixing layer and in the region of deceleration of two-phase pulsed jet. The greatest levels of the longitudinal velocity and the kinetic energy of turbulence are attained in the interval of pulse blow-on. At the subsequent moments of time the turbulence velocity and level monotonically decrease. The vortex cloud produced by the solitary pulse exists for a fairly long time (<i>t</i> ≈ 4 s) and has a time to penetrate into the surrounding space at a distance greater than 3 m.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 4","pages":"687 - 699"},"PeriodicalIF":1.0,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595418","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
Two-Layer Equilibrium Model of Miscible Inhomogeneous Fluid Flow 混溶不均匀流体流动的双层平衡模型
IF 1 4区 工程技术
Fluid Dynamics Pub Date : 2024-11-07 DOI: 10.1134/S0015462824603395
V. Yu. Liapidevskii
{"title":"Two-Layer Equilibrium Model of Miscible Inhomogeneous Fluid Flow","authors":"V. Yu. Liapidevskii","doi":"10.1134/S0015462824603395","DOIUrl":"10.1134/S0015462824603395","url":null,"abstract":"<p>Two-layer flow of a density-stratified fluid with mass transfer between the layers is considered. In the Boussinesq approximation, the equations of motion are reduced to a homogeneous quasilinear system of partial differential equations of mixed type. The flow parameters in the intermediate mixed layer are determined from the equilibrium conditions in a more general model of three-layer flow of a miscible fluid. In particular, the equilibrium conditions imply the constancy of the interlayer Richardson number in velocity-shift flows. A self-similar solution to the problem of breakdown of an arbitrary discontinuity (the lock-exchange problem) in the domain of hyperbolicity of the system under consideration is constructed. The transcritical flow regimes over a local obstacle are studied and the conditions under which the obstacle determines the upstream flow are determined. A comparison of steady-state and time-dependent solutions with the solutions obtained for the original three-layer models of miscible fluid flow is carried out.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 4","pages":"709 - 722"},"PeriodicalIF":1.0,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0015462824603395.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595419","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
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