Fluid Dynamics最新文献_第2页

Hydrodynamics of Gaseous Envelopes of Hot Jupiters 热木星气态包络的流体力学

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-03-09 DOI: 10.1134/S0015462824605163

D. V. Bisikalo, A. G. Zhilkin

{"title":"Hydrodynamics of Gaseous Envelopes of Hot Jupiters","authors":"D. V. Bisikalo, A. G. Zhilkin","doi":"10.1134/S0015462824605163","DOIUrl":"10.1134/S0015462824605163","url":null,"abstract":"We discuss the results of our studies of the dynamics and structure of extended envelopes of hot Jupiters. For calculations we used 3D numerical model, based on the approximation of multicomponent magnetohydrodynamics and allowing calculate the super-Alfvén, sub-Alfvén, and trans-Alfvén regimes of the stellar wind flow around the planet. The main attention in the work is paid to aspects of further development and testing of the model. Thus, the analysis of the calculation results taking into account magnetic viscosity showed that at short times of the order of the orbital period, the effects of magnetic field diffusion are insignificant and can be excluded from the calculations of fast-flowing processes associated with the impact of coronal mass ejections on the envelope. To take into account the processes occurring in the inner parts of the atmosphere, a modification of the code for the case of a spherical mesh was carried out, and 1D aeronomic model was developed. This provides a more correct specification of the initial and boundary conditions in the upper atmosphere of hot Jupiter and opens up new possibilities for obtaining a self-consistent solution that includes both the inner atmosphere and the exoplanet’s envelope. In general, the developed tools create a good basis for interpreting observations of the planned space mission “Spektr-UF/WSO-UV” and, in the long term, will allow determining the parameters of the stellar wind and coronal mass ejections from the host stars of these exoplanets.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 8","pages":"2362 - 2376"},"PeriodicalIF":1.0,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143581267","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

Erratum to: Evolution of Pressure Waves in Liquid Containing a Porous Partition Saturated with a Bubble Fluid 勘误：多孔隔板饱和气泡流体中的压力波演变

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-03-09 DOI: 10.1134/S0015462824080020

I. K. Gimaltdinov, A. S. Rodionov, O. Yu. Valiakhmetova

引用次数: 0

The Influence of Compressibility on the Interaction of a Clump with an Inhomogeneous Gaseous Layer

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-03-09 DOI: 10.1134/S0015462824605187

G. Y. Kotova, E. R. Shevchenko

{"title":"The Influence of Compressibility on the Interaction of a Clump with an Inhomogeneous Gaseous Layer","authors":"G. Y. Kotova, E. R. Shevchenko","doi":"10.1134/S0015462824605187","DOIUrl":"10.1134/S0015462824605187","url":null,"abstract":"This work is devoted to one possible mechanism for forming inhomogeneous structures at the periphery of HII regions: compression of primary condensations under radiation. According to the model used, as the HII region expands in an inhomogeneous medium, between the shock and ionization fronts a dense, rapidly moving layer of neutral gas is formed. The gas in front of the layer is heated by the shock wave, and the layer itself acquires acceleration under the action of the difference in pressures of ionized hydrogen in the HII region and neutral gas in front of the shock wave. In this work, we investigate the influence of compressibility on the dynamics of immersion of a clump into a layer, as well as the inhomogeneous structure of the density, temperature, and entropy fields. Particular attention is paid to the stage of the clump penetration into the layer. It was found that with a decrease in the polytropic index and a corresponding increase in the compressibility coefficient, Archimedes’ force, which affects the collapse of the cavity, weakens. To study the distribution of the cloud substance over time and identify the cloud material from the layer, the calculations of two-dimensional unsteady motions of an ideal perfect gas in a constant gravity field in the presence of local inhomogeneity were performed. It was found that when a clump interacts with an inhomogeneous layer at the stage of cavity formation, the heated gas moves in the direction of the clump, shifting the extremum in the distribution of parameters from the symmetry axis. The cloud itself is strongly deformed when penetrating a dense cold gas layer.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 8","pages":"2468 - 2474"},"PeriodicalIF":1.0,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143581086","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

Relativistic Astrospheres of Pulsars and Gamma-Ray Binaries: Modeling of Non-thermal Processes 脉冲星和伽马射线双星的相对论天体：非热过程建模

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-03-09 DOI: 10.1134/S0015462824605059

A. M. Bykov, A. E. Petrov, K. P. Levenfish

{"title":"Relativistic Astrospheres of Pulsars and Gamma-Ray Binaries: Modeling of Non-thermal Processes","authors":"A. M. Bykov, A. E. Petrov, K. P. Levenfish","doi":"10.1134/S0015462824605059","DOIUrl":"10.1134/S0015462824605059","url":null,"abstract":"Relativistic winds of the rotation powered pulsars in binary systems colliding with powerful winds of massive stars are producing astrospheres which are observed as bright gamma-ray sources above TeV photon energies. A long standing problem in high energy astrophysics is the nature of galactic accelerators of particles above PeV energies which are the sources of galactic cosmic rays and are producing PeV regime photons observed by ground based observatories. Recent 2D RMHD modeling revealed that gamma-ray binaries which harbor Gauss-range magnetic field in the winds collision region can accelerate particles above PeV. We present here 2D and 3D simulations of local structure of the winds collision region in gamma-ray binaries and show that in both cases the structures of magnetized flows are favorable for PeV proton acceleration. The strong magnetization of the winds of young massive stars results in prominent anisotropic shape of the relativistic pulsar wind astrosphere and may strongly affect the non-thermal emission of gamma-ray binaries. The sources can be bright in MeV emission regime and can indeed be the sources of PeV energy protons.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 8","pages":"2377 - 2391"},"PeriodicalIF":1.0,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143581266","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

Influence of Drag Forces and Interstellar Magnetic Fields on Radiation Driven Dust Arcs Around Runaway Stars 拖曳力和星际磁场对失控恒星周围辐射驱动尘埃弧的影响

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-03-09 DOI: 10.1134/S0015462824605151

I. P. Zabolotnyi, V. V. Izmodenov

{"title":"Influence of Drag Forces and Interstellar Magnetic Fields on Radiation Driven Dust Arcs Around Runaway Stars","authors":"I. P. Zabolotnyi, V. V. Izmodenov","doi":"10.1134/S0015462824605151","DOIUrl":"10.1134/S0015462824605151","url":null,"abstract":"Peculiarities of the interstellar dust distribution around runaway stars have been modeled in the frame of the cold gas model with the Lagrangian approach. Interstellar dust (ISD) particles move with respect to the star due to the relative motion of the star and interstellar gas. The stellar radiation pressure changes the trajectories of the particles forming a dust void cavity behind the star. The shape of the boundary of the cavity is parabolic. In addition to the radiation pressure force, ISD may suffer drug force due to interaction with protons and electrons and electromagnetic force. The effects of these forces are explored in the paper. We found that drag force pulls the cavity boundary closer to the star in the apex region and straightens the tail region into a cylindrical shape. We also found that the caustic structure in this case consists of multiple folds. On the other hand, the influence of the interstellar magnetic field depends on its orientation. We considered magnetic fields parallel and perpendicular to interstellar medium velocity. Under the influence of the magnetic field dust particles can penetrate void region due to gyration. In the presence of parallel magnetic field trajectories form a swallowtail caustics and dust arc is bounded. The effect of the perpendicular magnetic field is more complex, trajectories form cusp caustics and wave-shaped pattern in the tail region.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"59 8","pages":"2445 - 2452"},"PeriodicalIF":1.0,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143581272","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

Molecular Dynamics Analysis of Thermalization of a Microcanonical Ensemble

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-03-09 DOI: 10.1134/S0015462824605230

S. T. Surzhikov

引用次数: 0

Impact of Stochastic Acceleration on the Pickup Proton Distribution and ENA Fluxes in the Heliosphere

IF 1 4区工程技术

Fluid Dynamics Pub Date : 2025-03-09 DOI: 10.1134/S0015462824605175

I. I. Baliukin

引用次数: 0

Unstable Gas Flow in a Flat Channel under the Influence of a Transverse Force Field: Self-oscillations of the Jet 横向力场影响下平坦通道中的不稳定气体流：射流的自振荡