Fluid Dynamics最新文献

Enhancement of Separation Flow and Heat Transfer in a Boomerang-Type Groove on the Channel Wall

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-04-06 DOI: 10.1134/S0015462824604662

S. A. Isaev, I. A. Popov, D. V. Nikushchenko, A. G. Sudakov, A. A. Klyus, A. A. Mironov

{"title":"Enhancement of Separation Flow and Heat Transfer in a Boomerang-Type Groove on the Channel Wall","authors":"S. A. Isaev, I. A. Popov, D. V. Nikushchenko, A. G. Sudakov, A. A. Klyus, A. A. Mironov","doi":"10.1134/S0015462824604662","DOIUrl":"10.1134/S0015462824604662","url":null,"abstract":"The self-organization of a tornado-like vortex enhanced by the formation of an extraordinary transverse pressure drop and the onset of a negative pressure pole in the tornado core is observed in the case of a 45° deviation of the inlet section of streamwise oriented groove on the heated wall of plane-parallel channel with increase in the relative length of the section ξ, starting from 0.15. Tornado generation leads to the development of abnormal separation flow and heat transfer enhancement in the inlet inclined part of the groove. It is known that in the inclined rectilinear grooves the abnormal enhancement of separation flow and heat transfer is characterized by weakening of vortex structures and suppression of heat transfer in the end part of the groove. It is found that at the optimum relative length ξ the orientation of the end section of the groove along the flow in the channel leads to the penetration of intense swirling flow into the end zone of the boomerang-type groove and enhances heat transfer here. The optimal length of the inlet section ξ = 0.35 is determined. At this length, a 29% increase in the maximum heat transfer from the inner groove surface compared to the plane channel wall is achieved. In this case, the heat removal inside the boomerang-type groove is 1.2 times higher than that for the straight groove at the 45° inclination angle. The critical length of the inlet section (ξ = 0.7) starting from which the swirling flow leaves the groove without reaching its end is found. The critical length is characterized by the minimum relative hydraulic losses for the section bounded by the contour of the groove spot.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"60 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143784159","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

Construction of the Three-Dimensional Minimum-Wave-Drag Forebody of Given Length and with a Circular Base (Review)

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-04-06 DOI: 10.1134/S0015462824604716

A. N. Kraiko, N. I. Tillyaeva, I. A. Brailko

{"title":"Construction of the Three-Dimensional Minimum-Wave-Drag Forebody of Given Length and with a Circular Base (Review)","authors":"A. N. Kraiko, N. I. Tillyaeva, I. A. Brailko","doi":"10.1134/S0015462824604716","DOIUrl":"10.1134/S0015462824604716","url":null,"abstract":"We consider the problems occurring in constructing the nose parts (NP) of bodies of revolution realizing the wave drag minimum at a given body length and when the number of the planes of symmetry n ≥ 2. The axisymmetric solution of this problem had been given by I. Newton in his Philosophiae Naturalis Principia Mathematica within the framework of his own Newton formula (NF) for the pressure on the windward side of a body in flow suggested in the same study. The solution given by Newton without any explanations was not at once understood by aerodynamicists who turned to the solution of this problem and its certain generalizations at the mid-twentieth century. Newton’s Principia were translated into Russian by A.N. Krylov, who gave also detailed commentaries to this treatise, including the problem under discussion. However, even these comments could not help to understand Newton’s solution and it was only the Soviet aerodynamicists who could cope with them. Nevertheless, before long the three-dimensional NPs could be constructed within the framework of the NF; the drag of those bodies, which had firstly star-shaped and then circular bases, was smaller than that of the axisymmetric Newtonian NPs of the same length at n ≥ 2. The mathematicians, who started to deal with this problem at the end of the 20th century and the beginning of the 21st century, and had known nothing about the studies of aerodynamicists, turned to the same NF, prohibiting concave regions of the surfaces of the required NFs. The main result of their investigations within the framework of the NF is the NP that consists of n ≥ 2 identical inclined planes, adjoining lineate surfaces, and a leading flat face—a regular n-gon (a rectilinear segment at n = 2). However, for both the theory and applications it is important to know how they behave in at least an inviscid flow. The results of calculations of these flows according to Euler equations presented below are intended to reply to this question.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"60 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143784206","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

Diffusion and Deposition of Brownian Particles in the Boundary Layer in Flow of a Dispersed Mixture Past a Permeable Surface

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-04-06 DOI: 10.1134/S0015462824604285

T. R. Amanbaev

{"title":"Diffusion and Deposition of Brownian Particles in the Boundary Layer in Flow of a Dispersed Mixture Past a Permeable Surface","authors":"T. R. Amanbaev","doi":"10.1134/S0015462824604285","DOIUrl":"10.1134/S0015462824604285","url":null,"abstract":"The effect of mass transfer (owing to fluid injection or suction) with a surface in disperse flow on the processes of diffusion and deposition of Brownian particles in the boundary layer is studied. The equations of motion and diffusion of a dispersed mixture are presented in the boundary layer approximation with regard for the dependence of the effective viscosity of the suspension on the volume particle content. The boundary value problem is formulated in self-similar variables with regard for the fluid suction (injection) rate on the permeable surface. An analysis of the diffusion equation is carried out at small and large Schmidt numbers and in these limiting cases approximations of its solutions are found. In particular, it is shown that in the boundary layer, in the limit as the Schmidt number increases indefinitely, the derivative of the particle concentration with respect to the independent self-similar variable tends to the Dirac delta function. The results of numerical solution of the formulated boundary value problem obtained at various values of the constitutive parameters are discussed with reference to the plate boundary layer. It is found that in the presence of injection there exists a characteristic Schmidt number (depending on the injection intensity) such that a region without particles appears in the boundary layer at the higher Schmidt numbers. The effect of the injection intensity on the dimensions of this region is studied. The dependences of the diffusion particle flow toward the plate surface on the Schmidt number are analyzed in the case of the presence or absence of injection (suction).","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"60 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143784160","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

Experiments on the Nonlinear Development of Controlled Disturbances in the Region of Artificial Flow Inhomogeneity in the Flat-Plate Boundary Layer at Mach Number 2.5

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-04-06 DOI: 10.1134/S0015462824603358

A. D. Kosinov, M. V. Piterimova, N. V. Semionov, B. V. Smorodskii, A. A. Yatskikh

引用次数: 0

Generation of Thermogravitational Convection and Convective Diffusion in a Radiation-Heated Region

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-04-06 DOI: 10.1134/S0015462824604650

B. V. Borisov, G. V. Kuznetsov, V. I. Maksimov, T. A. Nagornova, F. Yu. Salikhov

引用次数: 0

Flows with an Overcompressed Detonation Wave in Variable-Area Channels

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-04-06 DOI: 10.1134/S0015462824604352

V. G. Aleksandrov, A. D. Egoryan, I. A. Filatov

引用次数: 0

Applied Problems of Radiative and Radiative-Conductive Heat Exchange

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-04-06 DOI: 10.1134/S0015462825600270

V. A. Tovstonog

{"title":"Applied Problems of Radiative and Radiative-Conductive Heat Exchange","authors":"V. A. Tovstonog","doi":"10.1134/S0015462825600270","DOIUrl":"10.1134/S0015462825600270","url":null,"abstract":"The tasks of radiative and radiative-conductive heat exchange in one form or another always accompany the creation of rocket and space structures. This is due to the widespread use of nonmetallic structural materials, which, as a rule, exhibit the property of partial transparency with respect to radiation, as well as the prevalence of heat exchange conditions in structures with a determining or prevailing effect of radiation. In the simplest formulations of such problems, the partial transparency of the material with respect to radiation from external sources and the relationship between radiation fields and temperature in the heated object are usually not taken into account. Nevertheless, their solution has practical significance in pulsed modes of radiation flux exposure; in calculations of the temperature state of structures made of materials that do not allow high-temperature heating; in approximate estimates of the temperature state, etc. In more complex cases, it is possible to take into account the relationship between radiation and temperature fields, the structural structure of the medium, the nonstationarity of heating conditions, physical and chemical transformations, etc. In this case, the efficiency of calculation algorithms, and the adequacy of the models used in relation to real processes, as well as the reliability of data on the optical and physical properties of the medium and the conditions of thermal exposure come to the fore. This article examines some applied problems of radiation and radiation-conductive heat exchange.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"60 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143784161","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 a Nanosecond Sliding Surface Discharge in Time-Dependent Supersonic Air Flow in a Channel

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-04-06 DOI: 10.1134/S0015462824603565

I. E. Ivanov, I. V. Mursenkova, A. S. Sazonov, N. N. Sysoev

{"title":"Investigation of a Nanosecond Sliding Surface Discharge in Time-Dependent Supersonic Air Flow in a Channel","authors":"I. E. Ivanov, I. V. Mursenkova, A. S. Sazonov, N. N. Sysoev","doi":"10.1134/S0015462824603565","DOIUrl":"10.1134/S0015462824603565","url":null,"abstract":"The regimes of development of a 500 ns sliding surface discharge are experimentally studied in time-dependent supersonic air flows in the channel of shock tube with a rectangular cross-section. The Mach numbers of the shock waves were from 2.30 to 5.00 at the initial air pressures from 2 to 100 Torr and the Mach numbers in the flow were from 1.18 to 1.66. A 100 mm-long sliding surface discharge was initiated at a given moment of time in different stages of the time-dependent supersonic flow after plane shock wave diffraction on an obstacle and in a quasistationary flow past the obstacle in the presence of an inclined shock wave. The discharge current and spatial radiation characteristics were analyzed. The high-speed shadowgraphy of the flow fields was carried out at the frequency up to 525 000 frames per second. The numerical modeling of the channel flow was performed within the framework of the Navier–Stokes equations. The comparison of the experimental and numerical results made it possible to establish the correlation between the parameters of a low-density zone formed as a result of the interaction between the oblique shock wave and a boundary layer and the regime in which the discharge current proceeds. The flow structure in the channel is analyzed after the discharge initiation, when a near-semi-cylindrical shock wave is formed. The comparison of the experimental and numerical results shows the thermal energy released in the discharge current region amounts to from 0.15 to 0.36 J.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"60 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143784205","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

Heliopause Stability

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-03-09 DOI: 10.1134/S0015462824605114

M. S. Ruderman

{"title":"Heliopause Stability","authors":"M. S. Ruderman","doi":"10.1134/S0015462824605114","DOIUrl":"10.1134/S0015462824605114","url":null,"abstract":"Interaction of the supersonic wind with the supersonic flow of the interstellar medium results in the development of interaction region called the heliospheric interphase. It is bounded by two shocks, termination and bow. The solar wind flow compressed at the termination shock and the interstellar medium flow compressed at the bow shock are separated by a tangential discontinuity called the heliopause. An important problem related to the physical processes in the heliosphere is the heliopause stability. We present a brief review of studies of two types of instabilities that can operate at the heliopause: the Kelvin–Helmholtz (KH) instability of the heliopause flanks and the Rayleigh–Taylor instability of the part of heliopause close to the apex point. Using the local analysis the stability of the magnetic-free heliopause flanks was considered, and then the effect of the magnetic field in the interstellar medium and solar wind was discussed. The RT instability in the vicinity of the apex point can be driven by the accelerated motion of the heliospheric interface toward the interstellar medium. It was studied both in the case of constant acceleration as well as acceleration oscillating with the period of the solar cycle. Another mechanism of driving the RT instability is the charge exchange between the hydrogen atoms and ions. This kind of instability was studied for the magnetic-free heliopause.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 8","pages":"2339 - 2352"},"PeriodicalIF":1.0,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143581082","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

Application of the Thin Shock Layer Model to the Determination of the Parameters of the Envelopes of Young Stellar Objects

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-03-09 DOI: 10.1134/S0015462824605096

K. V. Krasnobaev

{"title":"Application of the Thin Shock Layer Model to the Determination of the Parameters of the Envelopes of Young Stellar Objects","authors":"K. V. Krasnobaev","doi":"10.1134/S0015462824605096","DOIUrl":"10.1134/S0015462824605096","url":null,"abstract":"Classical problems of unsteady one-dimensional and two-dimensional explosive motions are generalized to the case of gas expansion by ionizing ultraviolet radiation in regions of active star formation. An essential feature of the developed model is the use of the ionization balance condition instead of the adiabaticity condition, which is invalid due to the interaction of gas with radiation. The model allows one to study gas dynamic phenomena in an inhomogeneous medium and in a non-stationary radiation field. The results of the calculations are compared with those obtained within the framework of the Cherny and Kompaneets approximations, and a physical interpretation of the differences that arise is given. It is analytically shown that for one-dimensional motions it is impossible to move a finite mass of gas to infinity in a finite time interval. A criterion is derived for such a two-dimensional density distribution in the gas envelope, at which a “break” of the envelope occurs in a finite time. An analysis of theoretically predicted properties of motions at different stages of the evolution of HII regions with observations is carried out. The analysis made it possible to establish new dependencies of the measured fluxes of ultraviolet, infrared and radio radiation on the parameters of the ionized and neutral gas involved in the motion.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 8","pages":"2353 - 2361"},"PeriodicalIF":1.0,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143581129","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