Fluid Dynamics最新文献

{"title":"CFD Analysis of Weapon Bay Missile Ejection at Various Mach Numbers","authors":"P. Tembhurnikar,&nbsp;MD. G. Sarwar,&nbsp;D. Sahoo","doi":"10.1134/S0015462824605333","DOIUrl":"10.1134/S0015462824605333","url":null,"abstract":"<p>The aerodynamic behaviour of missiles released from weapon bay cavities at supersonic velocities ranging from Mach 2 to Mach 5 is studied. The computation offers detailed examinations of the pressure fluctuations, the density variations, and the Mach number distributions. A particular attention is focused on the interaction of the shear layer at the leading edge of the cavity with the shock generated on the missile nose. The findings indicate minimal changes in the interaction between the shear layer at the cavity’s leading edge and the leading-edge shock produced at the missile’s nose at the Mach number range from 2 to 5. At the Mach number equal to 2, the interaction is relatively subdued, mainly affected by a detached shock wave with increased flow turning angle. Prandtl–Meyer expansion on both the nose tip and the tail end of the missile highlights the influence of compressibility. In contrast, at the Mach numbers equal to 3, 4, and 5, the interaction between the shear layer and the shock wave system becomes a notable factor that affects aerodynamic changes. In contrast, an intense detached bow shock wave prevails at the Mach number equal to 2. These findings offer crucial insights into the intricate flow dynamics surrounding missiles at high supersonic velocities, with implications for enhancing aerodynamic design and optimizing performance in future aerospace endeavours.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"60 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143925659","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}

{"title":"Method of Temperature Correlations for Estimating the Large-Scale Circulation Rate in the Case of Turbulent Convection of Liquid Metals in an Inclined Cylinder","authors":"A. D. Mamykin","doi":"10.1134/S0015462824604376","DOIUrl":"10.1134/S0015462824604376","url":null,"abstract":"<p>The potentials of the temperature correlation method in determining the mean velocities of liquid metal turbulent flows are investigated. The method uses the signals from temperature sensors arranged in line in the direction of large-scale circulation motion. As distinct from other, more conventional techniques, this indirect method can be used in the measurements in melt metals, which represent aggressive opaque media. The method is based on the Taylor hypothesis of the temperature disturbance field freezing in the velocity field on a certain level of flow turbulence. By fixing the passage of such disturbances through temperature sensors it is possible to calculate the flow velocity. The flow in the actual setups is usually inhomogeneous and developed turbulence arises only locally in the cavity. For this reason, though the method is absolute and does not need calibration, its applicability should to be verified in each particular case. In this study the method is applied to the problem of turbulent convection of liquid sodium (Prandtl number Pr = 0.0083) in a cylinder, whose length is greater than its diameter by the factor of 5, heated from one end and cooled from the other. In the flow regimes considered the cylinder is inclined to the vertical by an angle β, 18° ≤ β ≤ 90°. The Rayleigh number based on the cylinder diameter was 5 × 10⁶. An analysis of the data of experimental investigations and three-dimensional numerical calculations is performed. In the latter case the flow velocity is known for a fact and can be directly compared with the estimates obtained using the cross-correlation analysis. It is shown that the method of temperature correlations not always allows one to adequately estimate the mean velocities of regular large-scale sodium flows, that is, has its own restrictions. The method performs well in the conditions of moderate turbulent fluctuations of the temperature and velocity. The greatest error of the method takes place near the heat exchangers in the flow direction: a demonstrative explanation of the reasons for this error is proposed with reference to this example. The nonlinear dependence of the large-scale circulation amplitude on the angle of inclination of the cylinder is obtained; it has a maximum near 45°. The location of the maximum of this dependence is different from that for the cylinder with the aspect ratio 20 (60°–70°).</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"60 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143925618","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}

{"title":"Stimulation of Thrombus Dissolving by Magneto-Induced Circulation Currents","authors":"A. Yu. Musikhin,&nbsp;A. Yu. Zubarev","doi":"10.1134/S0015462824603711","DOIUrl":"10.1134/S0015462824603711","url":null,"abstract":"<p>The theoretical model and the method of its approximate analysis dealing with flows induced by a rotating magnetic field in the channel occupied by a non-magnetic fluid with an embedded ferrofluid layer are proposed. One of the channel ends is assumed to be closed (thrombotic). Some estimates of the velocity of convective-diffusion flow of a neutral impurity (thrombolytic) onto a thrombus in the channel with magnetically induced circulation currents are obtained and the effect of these currents on the thrombus dissolution rate is studied.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"60 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143925661","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}

{"title":"Effect of Surface Tension on Splashes of a Liquid during Drop Falling on a Rigid Obstacle","authors":"A. V. Bazilevskii,&nbsp;A. N. Rozhkov","doi":"10.1134/S001546282460490X","DOIUrl":"10.1134/S001546282460490X","url":null,"abstract":"<p>The impacts of water and ethyl alcohol drops on a small metal disk whose diameter (4 mm) is only slightly greater than the drop diameter (2.8 mm) are studied. The drops fell from a height of 0.10–0.65 m and reached a velocity of 1.40–3.57 m/s before impact. Using high-speed video recording, various stages of the drop collisions with the obstacle were recorded. It is found that when going over from water to ethyl alcohol under the same impact conditions, a noticeable increase in the maximum splash diameter and the time it takes to reach it is observed. Observations also show that transition from a continuous splash to a splash with fragmentation is determined exclusively by the impact Weber number, whose critical value is of the order of 100. The previously established power-law dependence of the maximum splash diameter on the impact Weber number is confirmed.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"60 2","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883604","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}

{"title":"Specific Features of Supersonic Flow past Bodies with Instantaneous Energy Input in a Gas Bubble Ahead of the Bow Shock","authors":"P. Yu. Georgievskii,&nbsp;V. A. Levin,&nbsp;O. G. Sutyrin","doi":"10.1134/S0015462824605588","DOIUrl":"10.1134/S0015462824605588","url":null,"abstract":"<p>The effect of instantaneous energy release (explosion) in the gas bubble region on supersonic flow past blunt bodies (sphere) and pointed bodies (ogival body and cone-cylinder combination) is considered when the explosion occurs in unperturbed freestream flow in the immediate neighborhood of the bow shock. Physically, such an effect on the flow can occur with energy input in the region of electric gas discharge or with detonation of a combustible gas mixture inside the bubble. It is found that, in addition to the direct effect of the explosive shock wave on the surface of the body, significant non-stationary changes in the gas-dynamic flow regimes past the bodies occur during the interaction of the bow shock with the dynamically varying explosion region (shock-compressed layer and cavity). In particular, focusing and cumulation effects, which can lead to secondary effects, are noted. The momentum of the latter is comparable to or even greater than the momentum of the direct impact of the blast wave.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"60 2","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0015462824605588.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883603","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}

{"title":"Analysis of Wave Motions of a Viscous Incompressible Fluid on a Rotating Wall in the Presence of a Cross Flow","authors":"A. A. Gurchenkov","doi":"10.1134/S0015462824604698","DOIUrl":"10.1134/S0015462824604698","url":null,"abstract":"<p>The non-stationary problem of wave motions of a viscous incompressible fluid on a rotating plate is considered. An analytical solution of three-dimensional time-dependent hydrodynamic equations is given. The velocity field in flow of a viscous fluid that occupies half-space bounded by a plane wall is determined. The fluid together with the bounding plane rotates as a single whole at a constant angular velocity about a direction non-perpendicular to the plane. Non-stationary flow is induced by suddenly starting longitudinal oscillations of the wall and by injection (suction) of the medium produced along the normal to the wall surface. A number of special cases of wall motion are considered. Based on the obtained results, individual structures of the boundary layers near the wall are investigated.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"60 2","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883605","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}

{"title":"Progress on Ablation of Nozzle Throat Inserts in Solid Rocket Motors","authors":"Z. T. Zhou,&nbsp;T. Y. Cao,&nbsp;Y. Q. Li,&nbsp;L. Ji","doi":"10.1134/S0015462824605254","DOIUrl":"10.1134/S0015462824605254","url":null,"abstract":"<p>During engine operation, the nozzle throat insert components are subjected to high temperatures, pressures, velocities, and erosive gas flow, leading to changes in the nozzle throat diameter, which in turn affect the engine thrust performance. This paper elaborates on the erosion behavior and the mechanism of solid rocket motor throat inserts from three aspects: theoretical study, experimental study, and numerical simulation. In the field of theoretical research, the main focus is on studying empirical formulas, theoretical ablation models, and improved methods for predicting ablation. These studies involve summarizing the characteristics of ablation and proposing simplified ablation models; in terms of the experimental study, the common ablation experimental methods are summarized and the principles, advantages and disadvantages of several types of typical ablation experimental methods are analyzed. In the numerical simulation, more comprehensive ablation models and improved ablation methods are proposed based on the theoretical and experimental contents. Finally, some suggestions are made for the following ablation researches to provide reference and references for future throat insert ablation researches.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"60 2","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883627","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}

{"title":"Structure of Subsonic Separation Flow past Cylindrical Cavities of Various Shapes in Plan on the Wall of a Plane Channel","authors":"M. A. Zubin,&nbsp;A. F. Zubkov,&nbsp;A. Yu. Chulyunin","doi":"10.1134/S0015462824605370","DOIUrl":"10.1134/S0015462824605370","url":null,"abstract":"<p>The results of experimental and numerical studies of subsonic turbulent flow past cylindrical cavities of various shapes in plan on the plate or on the wall of a plane–parallel channel are present. The proposed shapes of cavities are modifications of a finite-span cylindrical trench with rounded spherical end faces, known in the literature as an oval-trench dimple (OTD). The pressure coefficient distributions are obtained and the patterns of surface streamlines are visualized for modified cylindrical cavities of <i>V</i>- and drop-shaped configurations of various relative depths. A comparative estimate of the intensity of reverse separation flow in oval-trench dimples of conventional and modified shapes is given. Such a flow affects the thermal-hydraulic characteristics of the surfaces with artificial relief. A comparison of the experimental results and the calculation carried out within the RANS technology showed that the proposed approach can be used in search for the optimum shape of the elements of artificial reliefs of heat exchange surfaces.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"60 2","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883629","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}

{"title":"Mathematical Model of Rotational Oscillations of a Porous Spherical Shell with a Gas Cavity in Viscous Fluid","authors":"O. A. Bazarkina,&nbsp;N. G. Taktarov","doi":"10.1134/S0015462824605102","DOIUrl":"10.1134/S0015462824605102","url":null,"abstract":"<p>A mathematical model of viscous fluid flow induced by the rotational-oscillatory motion of a submerged porous spherical shell with a spherical gas cavity is considered. In the Stokes approximation, analytical solutions are obtained for the time-dependent Brinkman equation that describes viscous fluid flow in the porous medium and the Navier–Stokes equation that describes viscous fluid flow outside the porous medium. An analysis of the obtained mathematical model is given. The case of uniform rotation about a fixed axis of the porous spherical shell with a spherical gas cavity inside it in a viscous fluid is considered.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"60 2","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883557","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}

{"title":"Singularity Problem for One-Dimensional Steady-State Gas Dynamics Problems","authors":"D. E. Khazov","doi":"10.1134/S001546282460562X","DOIUrl":"10.1134/S001546282460562X","url":null,"abstract":"<p>One-dimensional gas dynamics models are used to analyze flows whose parameters depend on a single spatial variable. Such models quickly and accurately predict changes in flow parameters. In the stationary case, such flows are described by ordinary differential equations. At velocities close to the sonic speeds, the flow can pass through the speed of sound, i.e., pass through a critical point. From a mathematical point of view, it is a question of occurrence of a singularity. The presence of a singularity causes difficulties in obtaining the solutions. The study considers a method for overcoming these difficulties using examples of flow in a channel of an arbitrary cross-section in the presence of friction, heat and mass transfer.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"60 2","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883606","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}