The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform
V G Baryshevsky - One of the best experts on this subject based on the ideXlab platform.
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optical spin rotation phenomenon and spin filtering of antiproton proton deuteron beams in a pseudomagnetic field of a polarized target the possibility of measuring the real part of the coherent Zero Angle scattering amplitude
arXiv: High Energy Physics - Phenomenology, 2011Co-Authors: V G BaryshevskyAbstract:It is shown that in the experiments dedicated for producing of polarized beams of antiprotons during their passage through a polarized gas target placed in a storage ring it is possible to measure not only spin-dependent total cross-sections of antiproton scattering by the proton (deuteron), but also the spin-dependent real part of the coherent Zero-Angle scattering amplitude in the process of production of a polarized beam of antiprotons.
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rotation of particle spin in a storage ring with a polarized beam and measurement of the particle edm tensor polarizability and elastic Zero Angle scattering amplitude
Journal of Physics G, 2008Co-Authors: V G BaryshevskyAbstract:Equations of particle spin motion in a storage ring are obtained considering contributions from the tensor electric and magnetic polarizabilities of the particle along with contributions from the spin rotation and birefringence effects in a polarized internal target. The study of the spin rotation and birefringence effects for a particle in a high-energy storage ring provides for measuring both the spin-dependent real part of the coherent elastic Zero-Angle scattering amplitude and tensor electric (magnetic) polarizabilities.
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spin rotation and birefringence effect for a particle in a high energy storage ring and measurement of the real part of the coherent elastic Zero Angle scattering amplitude electric and magnetic polarizabilities
arXiv: High Energy Physics - Phenomenology, 2005Co-Authors: V G Baryshevsky, A A GurinovichAbstract:In the present paper the equations for the spin evolution of a particle in a storage ring are analyzed considering contributions from the tensor electric and magnetic polarizabilities of the particle. Study of spin rotation and birefringence effect for a particle in a high energy storage ring provides for measurement as the real part of the coherent elastic Zero-Angle scattering amplitude as well as tensor electric and magnetic polarizabilities. We proposed the method for measurement the real part of the elastic coherent Zero-Angle scattering amplitude of particles and nuclei in a storage ring by the paramagnetic resonance in the periodical in time nuclear pseudoelectric and pseudomagnetic fields.
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phenomena of spin rotation and oscillation of particles atoms molecules containing in a trap blowing on by wind of high energy particles in storage ring new method of measuring of spin dependent part of Zero Angle coherent scattering amplitude
arXiv: High Energy Physics - Phenomenology, 2002Co-Authors: V G BaryshevskyAbstract:New experiment arrangement to study spin rotation and oscillation of particles of gas target through which beam of high energy particles passes is discussed. Such experiment arrangement make it realizable for storage ring and allows to study Zero-Angle scattering amplitude at highest possible energies. Life-time of particle beam in storage ring can reach several hours and even days. Life-time of particle in gas target (gas trap) is long too. Particles circulate in storage ring with frequency $\nu$ of several MHz that yields to the $\nu$-fold increase of density of high energy particles beam blowing gas trap in comparison with single passing case. Finally, this causes perfectly acceptable Angle of spin rotation of particles containing in gas cell. Relation between index of refraction and effective potential energy of a particle in a medium is discussed. Phenomenon of spin rotation of a particle captured to a trap under the action of a beam of polarized particles is considered. Expressions for effective potential energy and Angle of spin rotation are derived for particles in a trap. Rrotation and oscillation of deuteron spin is studied. Estimations for Angle of rotation show that the effect can be experimentally observed.
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Spin oscillations of high-energy particles (nuclei) passing through matter and the possibility of measuring the spin-dependent part of the amplitude of Zero-Angle elastic coherent scattering
Journal of Physics G, 1993Co-Authors: V G BaryshevskyAbstract:It is shown that as particles of spin S>or=1 pass through matter, a phenomenon arises which is similar to light birefringence in uniaxial and biaxial optically anisotropic crystals. The phenomenon allows one to determine real and imaginary parts of a spin-dependent amplitude of Zero-Angle elastic coherent scattering.
V. L. Lyuboshitz - One of the best experts on this subject based on the ideXlab platform.
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Spin structure of the “Forward” nucleon charge-exchange reaction n + p → p + n and the deuteron charge-exchange breakup
Physics of Atomic Nuclei, 2011Co-Authors: V. L. LyuboshitzAbstract:The structure of the nucleon charge-exchange process n + p → p + n is investigated basing on the isotopic invariance of the nucleon-nucleon scattering. Using the operator of permutation of the spin projections of the neutron and proton, the connection between the spin matrices, describing the amplitude of the nucleon charge-exchange process at Zero Angle and the amplitude of the elastic scattering of the neutron on the proton in the “backward” direction, has been considered. Due to the optical theorem, the spin-independent part of the differential cross section of the process n + p → p + n at Zero Angle for unpolarized particles is expressed through the difference of total cross sections of unpolarized proton-proton and neutron-proton scattering. Meantime, the spin-dependent part of this cross section is proportional to the differential cross section of the deuteron charge-exchange breakup d + p → (pp) + n at Zero Angle at the deuteron momentum kd = 2 kn (kn is the initial neutron momentum). Analysis shows that, assuming the real part of the spin-independent term of the “forward” amplitude of the process n + p → p + n to be smaller or of the same order as compared with the imaginary part, in the wide range of neutron laboratory momenta kn > 700 MeV/c the main contribution into the differential cross section of the process n + p → p + n at Zero Angle is provided namely by the spin-dependent term.
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n + p → p + n and the Deuteron Charge-Exchange Breakup *
2011Co-Authors: V. L. LyuboshitzAbstract:The structure of the nucleon charge-exchange process n + p → p + n is investigated basing on the isotopic invariance of the nucleon-nucleon scattering. Using the operator of permutation of the spin projections of the neutron and proton, the connection between the spin matrices, describing the amplitude of the nucleon charge-exchange process at Zero Angle and the amplitude of the elastic scattering of the neutron on the proton in the "backward" direction, has been considered. Due to the optical theorem, the spin-independent part of the differential cross section of the process n + p → p + n at Zero Angle for unpolarized particles is expressed through the difference of total cross sections of unpolarized proton-proton and neutron-proton scattering. Meantime, the spin-dependent part of this cross section is proportional to the differential cross section of the deuteron charge-exchange breakup d + p → (pp )+ n at Zero Angle at the deuteron momentum kd =2 kn (kn is the initial neutron momentum). Analysis shows that, assuming the real part of the spin-independent term of the "forward" amplitude of the process n + p → p + n to be smaller or of the same order as compared with the imaginary part, in the wide range of neutron laboratory momenta kn > 700 MeV/c the main contribution into the differential cross section of the process n + p → p + n at Zero Angle is provided namely by the spin-dependent term.
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Spin structure of the charge‐exchange process n + p → p + n at Zero Angle
AIP Conference Proceedings, 2007Co-Authors: V. L. LyuboshitzAbstract:The structure of the nucleon charge‐exchange process n + p → p + n is investigated basing on the isotopic invariance of the nucleon‐nucleon scattering. Using the operator of permutation of the spin projections of the neutron and proton, the connection between the spin matrices, describing the amplitude of the nucleon charge‐exchange process at Zero Angle and the amplitude of the elastic scattering of the neutron on the proton in the “backward” direction, has been obtained. Due to the optical theorem, the spin‐independent part of the differential cross‐section of the process n + p → p + n at Zero Angle for unpolarized particles is expressed through the difference of total cross‐sections of unpolarized proton‐proton and neutron‐proton scattering. Meantime, the spin‐dependent part of this cross‐section is proportional to the differential cross‐section of the deuteron charge‐exchange breakup d + p → (pp) + n at Zero Angle at the deuteron momentum kd = 2kn (kn is the initial neutron momentum). Analysis shows t...
D E Hastings - One of the best experts on this subject based on the ideXlab platform.
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ionospheric plasma flow over large high voltage space platforms i ion plasma time scale interactions of a plate at Zero Angle of attack
Physics of fluids. B Plasma physics, 1992Co-Authors: J Wang, D E HastingsAbstract:Theory and particle simulation results are presented for the ionospheric plasma flow over large, high‐voltage space platforms. In this paper, dynamic interactions of a negatively biased plate at a Zero Angle of attack on the ion‐plasma–time scale are emphasized. Results of the transient plasma response to a rapid surface potential change show that ion‐acoustic disturbances are generated by the leading edge, and they evolve to form a Mach wedge expansion fan. The transient ion current exhibits a strong overshoot in the first few ion‐plasma periods. It is shown that the current overshoot is due to the ions trapped within the initial sheath, and its magnitude is proportional to the plate dimension and the square root of the surface voltage. Simulations of time‐dependent interactions of a plate connected to external circuits are also performed. A rapidly changing voltage source may cause a very complex transient current and surface voltage due to the coupling of the transient plasma and circuit properties. In...
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Ionospheric plasma flow over large high‐voltage space platforms. I: Ion‐plasma–time scale interactions of a plate at Zero Angle of attack
Physics of fluids. B Plasma physics, 1992Co-Authors: J Wang, D E HastingsAbstract:Theory and particle simulation results are presented for the ionospheric plasma flow over large, high‐voltage space platforms. In this paper, dynamic interactions of a negatively biased plate at a Zero Angle of attack on the ion‐plasma–time scale are emphasized. Results of the transient plasma response to a rapid surface potential change show that ion‐acoustic disturbances are generated by the leading edge, and they evolve to form a Mach wedge expansion fan. The transient ion current exhibits a strong overshoot in the first few ion‐plasma periods. It is shown that the current overshoot is due to the ions trapped within the initial sheath, and its magnitude is proportional to the plate dimension and the square root of the surface voltage. Simulations of time‐dependent interactions of a plate connected to external circuits are also performed. A rapidly changing voltage source may cause a very complex transient current and surface voltage due to the coupling of the transient plasma and circuit properties. In...
S A Isaev - One of the best experts on this subject based on the ideXlab platform.
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Numerical simulation and experiments on turbulent air flow around the semi-circular profile at Zero Angle of attack and moderate Reynolds number
Computers & Fluids, 2019Co-Authors: S A Isaev, A G Sudakov, A E Usachov, P. A. Baranov, Igor Popov, S. V. Guvernyuk, Alexei Sinyavin, Alexei Chulyunin, A. B. Mazo, Dennis DemidovAbstract:Abstract Two-dimensional flow around a semi-circular profile at the Zero Angle of attack and at Re = 50000 on the self-oscillatory period is extensively studied by the URANS method involving the standard semi-empirical SST turbulence models, the SST turbulence model with the correction for streamline curvature modified within the Rodi-Leschziner-Isaev and Smirnov-Menter approaches, as well as involving Hanjalic's four-parameter eddy viscosity elliptic relaxation model and its analog - eddy viscosity elliptic blending model proposed in the present work. This has been done with the use of different-structure grids (multiblock with structured overlapping and unstructured composite). Different numerical approximation methods realized in six codes (VP2/3, SigmaFlow, Fluent, CFX, OpenFOAM, and StarCCM+) are used. An underestimation (up to 30%) of time-averaged integral aerodynamic loads is revealed by means of the standard near-wall SST model. This is explained by the high vortex viscosity production in the profile wake. Wind tunnel tests show that the location of cutoff washers on the semi-circular profile provides a quasi-two-dimensional flow around it and allows applying measurement data to verify two-dimensional turbulent flow. The best agreement of experimental results and numerical predictions when comparing the Strouhal number and time-averaged surface pressure coefficient distributions is achieved using both the modified SST model with the correction for streamline curvature and the modified eddy viscosity elliptic blending model. When the SST model with the correction for streamline curvature, modified within the Rodi-Leschziner-Isaev, Smirnov-Menter and Durbin approaches, is used, all the above codes yield close predictions of a vertical aerodynamic load on the oscillation period.
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Controlling the Flow past a Semicircular Airfoil at Zero Angle of Attack Using Slot Suction in One or Two Vortex Cells for Attaining Extremal Lift
Technical Physics Letters, 2017Co-Authors: S A Isaev, A G Sudakov, P. A. Baranov, Igor Popov, A E UsachovAbstract:Calculations using multiblock computational technologies and a model of shear-stress transport modified with allowance for the curvature of streamlines in turbulent airflow were performed at a Zero Angle of attack for a semicircular airfoil containing one or two surface vortex cells with slot suction. The results showed evidence of stabilization of a nearly undetached flow and attainment of an extremal lift of C y = 5.2 and a lift-to-drag ratio of K = 24 with allowance for energy losses for suction in the vortex cells.
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ensuring safe descend of reusable rocket stages numerical simulation and experiments on subsonic turbulent air flow around a semi circular cylinder at Zero Angle of attack and moderate reynolds number
Acta Astronautica, 2017Co-Authors: S A Isaev, A G Sudakov, A E Usachov, P. A. Baranov, Igor Popov, S. V. Guvernyuk, Alexei Sinyavin, A. B. Mazo, Alexei Chylunin, Eugeny KalininAbstract:Abstract Two-dimensional flow around semi-circular cylinder at Zero Angle of attack and at Re = 50000 during the self-oscillatory regime has been extensively studied within the URANS method with the use of different-structure grids (multiblock, structured overlapping, unstructured composite), the SST turbulence model and its versions (1993) and (2003) considering the streamline curvature influence modified within the Rodi–Leschziner–Isaev approach and numerical different-approximation methods realized in two codes (VP2/3, Fluent). Experiments have been made on flow around a semi-circular cylinder in the wind tunnel of the Lomonosov Moscow State University, Institute of Mechanics to obtain data for verification of numerical predictions. The double-mode character of a periodic time history of a drag force caused by a periodically forming and disappearing jet flap and acting upon a body is explained. With increasing compressibility at a Mach number ranging from 0 to 0.5, it is observed that periodic flow around the semi-circular cylinder is restructured, and the time history of the drag force acting upon it is described by a dependence close to a sinusoidal one. It is found that, as the Mach number is increased, pressure field distortions in the form of concentric cylindrical waves propagating from the semi-circular cylinder and the vortex street behind it grow over the infrasonic range.
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Ensuring safe descend of reusable rocket stages – Numerical simulation and experiments on subsonic turbulent air flow around a semi-circular cylinder at Zero Angle of attack and moderate Reynolds number
Acta Astronautica, 2017Co-Authors: S A Isaev, A G Sudakov, A E Usachov, P. A. Baranov, Igor Popov, S. V. Guvernyuk, Alexei Sinyavin, A. B. Mazo, Alexei Chylunin, Eugeny KalininAbstract:Abstract Two-dimensional flow around semi-circular cylinder at Zero Angle of attack and at Re = 50000 during the self-oscillatory regime has been extensively studied within the URANS method with the use of different-structure grids (multiblock, structured overlapping, unstructured composite), the SST turbulence model and its versions (1993) and (2003) considering the streamline curvature influence modified within the Rodi–Leschziner–Isaev approach and numerical different-approximation methods realized in two codes (VP2/3, Fluent). Experiments have been made on flow around a semi-circular cylinder in the wind tunnel of the Lomonosov Moscow State University, Institute of Mechanics to obtain data for verification of numerical predictions. The double-mode character of a periodic time history of a drag force caused by a periodically forming and disappearing jet flap and acting upon a body is explained. With increasing compressibility at a Mach number ranging from 0 to 0.5, it is observed that periodic flow around the semi-circular cylinder is restructured, and the time history of the drag force acting upon it is described by a dependence close to a sinusoidal one. It is found that, as the Mach number is increased, pressure field distortions in the form of concentric cylindrical waves propagating from the semi-circular cylinder and the vortex street behind it grow over the infrasonic range.
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estimation of the lifetime of a trapped vortex in a circular cavern on a semicircular airfoil streamlined at a Zero Angle of attack after switching off slot suction
Technical Physics Letters, 2017Co-Authors: S A Isaev, A G Sudakov, P. A. Baranov, Igor Popov, A E UsachovAbstract:The restructuring of the periodic structure of a turbulent streamline for a semicircular airfoil at a Zero Angle of attack with a system of slot suction from the circular cavern switched off is calculated. Multiblock numerical methods are applied for solution of Reynolds-averaged nonstationary Navier–Stokes equations closed using the modified shear-stress transfer model taking into account flow line curvature. The lifetime of a trapped vortex in a circular cavern is estimated.
A E Usachov - One of the best experts on this subject based on the ideXlab platform.
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Numerical simulation and experiments on turbulent air flow around the semi-circular profile at Zero Angle of attack and moderate Reynolds number
Computers & Fluids, 2019Co-Authors: S A Isaev, A G Sudakov, A E Usachov, P. A. Baranov, Igor Popov, S. V. Guvernyuk, Alexei Sinyavin, Alexei Chulyunin, A. B. Mazo, Dennis DemidovAbstract:Abstract Two-dimensional flow around a semi-circular profile at the Zero Angle of attack and at Re = 50000 on the self-oscillatory period is extensively studied by the URANS method involving the standard semi-empirical SST turbulence models, the SST turbulence model with the correction for streamline curvature modified within the Rodi-Leschziner-Isaev and Smirnov-Menter approaches, as well as involving Hanjalic's four-parameter eddy viscosity elliptic relaxation model and its analog - eddy viscosity elliptic blending model proposed in the present work. This has been done with the use of different-structure grids (multiblock with structured overlapping and unstructured composite). Different numerical approximation methods realized in six codes (VP2/3, SigmaFlow, Fluent, CFX, OpenFOAM, and StarCCM+) are used. An underestimation (up to 30%) of time-averaged integral aerodynamic loads is revealed by means of the standard near-wall SST model. This is explained by the high vortex viscosity production in the profile wake. Wind tunnel tests show that the location of cutoff washers on the semi-circular profile provides a quasi-two-dimensional flow around it and allows applying measurement data to verify two-dimensional turbulent flow. The best agreement of experimental results and numerical predictions when comparing the Strouhal number and time-averaged surface pressure coefficient distributions is achieved using both the modified SST model with the correction for streamline curvature and the modified eddy viscosity elliptic blending model. When the SST model with the correction for streamline curvature, modified within the Rodi-Leschziner-Isaev, Smirnov-Menter and Durbin approaches, is used, all the above codes yield close predictions of a vertical aerodynamic load on the oscillation period.
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Controlling the Flow past a Semicircular Airfoil at Zero Angle of Attack Using Slot Suction in One or Two Vortex Cells for Attaining Extremal Lift
Technical Physics Letters, 2017Co-Authors: S A Isaev, A G Sudakov, P. A. Baranov, Igor Popov, A E UsachovAbstract:Calculations using multiblock computational technologies and a model of shear-stress transport modified with allowance for the curvature of streamlines in turbulent airflow were performed at a Zero Angle of attack for a semicircular airfoil containing one or two surface vortex cells with slot suction. The results showed evidence of stabilization of a nearly undetached flow and attainment of an extremal lift of C y = 5.2 and a lift-to-drag ratio of K = 24 with allowance for energy losses for suction in the vortex cells.
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ensuring safe descend of reusable rocket stages numerical simulation and experiments on subsonic turbulent air flow around a semi circular cylinder at Zero Angle of attack and moderate reynolds number
Acta Astronautica, 2017Co-Authors: S A Isaev, A G Sudakov, A E Usachov, P. A. Baranov, Igor Popov, S. V. Guvernyuk, Alexei Sinyavin, A. B. Mazo, Alexei Chylunin, Eugeny KalininAbstract:Abstract Two-dimensional flow around semi-circular cylinder at Zero Angle of attack and at Re = 50000 during the self-oscillatory regime has been extensively studied within the URANS method with the use of different-structure grids (multiblock, structured overlapping, unstructured composite), the SST turbulence model and its versions (1993) and (2003) considering the streamline curvature influence modified within the Rodi–Leschziner–Isaev approach and numerical different-approximation methods realized in two codes (VP2/3, Fluent). Experiments have been made on flow around a semi-circular cylinder in the wind tunnel of the Lomonosov Moscow State University, Institute of Mechanics to obtain data for verification of numerical predictions. The double-mode character of a periodic time history of a drag force caused by a periodically forming and disappearing jet flap and acting upon a body is explained. With increasing compressibility at a Mach number ranging from 0 to 0.5, it is observed that periodic flow around the semi-circular cylinder is restructured, and the time history of the drag force acting upon it is described by a dependence close to a sinusoidal one. It is found that, as the Mach number is increased, pressure field distortions in the form of concentric cylindrical waves propagating from the semi-circular cylinder and the vortex street behind it grow over the infrasonic range.
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Ensuring safe descend of reusable rocket stages – Numerical simulation and experiments on subsonic turbulent air flow around a semi-circular cylinder at Zero Angle of attack and moderate Reynolds number
Acta Astronautica, 2017Co-Authors: S A Isaev, A G Sudakov, A E Usachov, P. A. Baranov, Igor Popov, S. V. Guvernyuk, Alexei Sinyavin, A. B. Mazo, Alexei Chylunin, Eugeny KalininAbstract:Abstract Two-dimensional flow around semi-circular cylinder at Zero Angle of attack and at Re = 50000 during the self-oscillatory regime has been extensively studied within the URANS method with the use of different-structure grids (multiblock, structured overlapping, unstructured composite), the SST turbulence model and its versions (1993) and (2003) considering the streamline curvature influence modified within the Rodi–Leschziner–Isaev approach and numerical different-approximation methods realized in two codes (VP2/3, Fluent). Experiments have been made on flow around a semi-circular cylinder in the wind tunnel of the Lomonosov Moscow State University, Institute of Mechanics to obtain data for verification of numerical predictions. The double-mode character of a periodic time history of a drag force caused by a periodically forming and disappearing jet flap and acting upon a body is explained. With increasing compressibility at a Mach number ranging from 0 to 0.5, it is observed that periodic flow around the semi-circular cylinder is restructured, and the time history of the drag force acting upon it is described by a dependence close to a sinusoidal one. It is found that, as the Mach number is increased, pressure field distortions in the form of concentric cylindrical waves propagating from the semi-circular cylinder and the vortex street behind it grow over the infrasonic range.
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estimation of the lifetime of a trapped vortex in a circular cavern on a semicircular airfoil streamlined at a Zero Angle of attack after switching off slot suction
Technical Physics Letters, 2017Co-Authors: S A Isaev, A G Sudakov, P. A. Baranov, Igor Popov, A E UsachovAbstract:The restructuring of the periodic structure of a turbulent streamline for a semicircular airfoil at a Zero Angle of attack with a system of slot suction from the circular cavern switched off is calculated. Multiblock numerical methods are applied for solution of Reynolds-averaged nonstationary Navier–Stokes equations closed using the modified shear-stress transfer model taking into account flow line curvature. The lifetime of a trapped vortex in a circular cavern is estimated.
