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Heat Transfer and Fluid Flow over a Single Disk in a Fluid Rotating as a Rigid Body

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Journal of Thermal Science 2004年第3期13卷 279-282页

作者： Igor V. shevchuk Matthias H. BUSCHMANN Institute of Engineering Thermophysics Ukrainian National Academy of Sciences 2a Zhelyabov St. Kiev 03057 UkraineInstitute of Fluid Mechanics Dresden University of Technology 01062 Dresden Germany

Laminar heat transfer problem is analyzed for a disk rotating with the angular speed ωin a co-rotating fluid (with the angular speed Ω). The fluid is swirled in accordance with a forced-vortex law, it rotates as a solid body at β= Ω/ω= const. Radial variation of the disk’s surface temperature follows a power law. An exact numerical solution of the problem is obtained basing on the self-similar profiles of the local temperature of fluid, its static pressure and velocity components. Numerical computations were done at the Prandtl numbers Pr = 1(?)0.71. It is shown that with increasing βboth radial and tangential components of shear stresses decrease, and to zero value at β= 1. Nusselt number is practically constant at β= 0(?) 0.3 (and even has a point of a maximum in this region); Nu decrease noticeably for larger βvalues.

关键词： rotating disk heat transfer fluid flow Nusselt number swirl.

High resolution imaging using scanning ion conductance microscopy with improved distance feedback control

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Progress in Natural Science:Materials International 2008年第6期18卷 671-677页

作者： Nicholas Johnson Victor Ostanin Andrew shevchuk Yuri korchev David klenerman Department of Chemistry University of CambridgeLensfield RoadCambridge CB2 1EWUnited Kingdom Division of Medicine Imperial College LondonMRC Clinical Sciences CentreHammersmith CampusLondon W12 0NNUnited Kingdom

Microscopy is an essential technique for observation on living *** is currently great interest in applying scanning probe microscopy to image-living biological cells in their natural environment at the nanometer *** ion conductance microscopy is a new form of scanning probe microscopy,which enables non-contact high-resolution imaging of living biological *** on a scanned nanopipette in physiological buer,the distance feedback control uses the ion current to control the distance between the pipette tip and the sample ***,this feedback control has diculties over slopes on convoluted cell surfaces,which limits its *** this study,we present an improved form of feedback control that removes the contribution of up to the third-order slope from the ion current signal,hence providing a more accurate signal for controlling the *** show that this allows faster and lower noise topographic high-resolution imaging.

关键词： Living biological cells Scanning ion conductance microscopy Distance feedback control

Laminar Forced Convection in Curved Channel with Vortex Structures

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Journal of Thermal Science 2004年第2期13卷 143-149,162页

作者： A.A. AVRAMENkO S.G. kOBZAR I.V. shevchuk A.V. kUZNETSOV B.I. BASOk Institute of Engineering Thermophysics National Academy of SciencesKievUkraine Center for Energy Research National University of MexicoAp.P.3462580TemixcoMor.Mexico Dept.of Mechanical and Aerospace Engineering North Carolina State UniversityCampus Box 7910RaleighNC 27606-7910USA

Theoretical and experimental investigations of heat transfer in flat curvilinear channel have been carried out. Linear and non-linear effects of Dean vortexes on intensity of heat transfer were taken into account. The linear effect, which describe harmonic (sinuous) variation of the heat transfer coefficient near the concave surface of the channel and the non-linear effect causes the general increase of the heat transfer coefficient due to augmentation of heat transfer engendered by the Dean vortexes. For both effects, mathematical relations were obtained in the form of quadratures. These numerical results were modified to the form convenient in engineering calculations. The investigations have shown that both linear and nonlinear components grow up with the Dean number. Nonlinear component Q0T increases more abruptly, while the linear one Q1T is more conservative. This is a confirmation of stability of vortex structures.

关键词： heat transfer Dean vortexes curvilinear channel quadrature.

Monetary Model of Exchange Rate Determination： Evidence From the Czech Republic, Hungary, and Poland

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Journal of Modern Accounting and Auditing 2014年第1期10卷 97-103页

作者： Victor shevchuk Cracow University of Technology Cracow Poland

Using a monetary model of exchange rate determination that suggests a strong link between the nominal exchange rate and a set of monetary fundamentals, exchange rate dynamics for the Czech Republic, Hungary, and Poland is studied. As the cointegration relationship among exchange rate, output, and the monetary fundamentals (money supply and interest rate) is found, vector autoregressions (VAR)/vector error-correction (VEC) and two-stage least squares (2SLS) error-correction models are used in this context, since both approaches allow estimating short-run correlations between exchange rates and fundamentals while taking into account the existent long-run exchange rate constraints. Based on the quarterly data for the period of 1998-2012, it is found that for all countries, an increase in the money supply, domestic output slowdown, or stronger growth abroad are factors behind a nominal exchange rate depreciation, just as predicted by the monetary model of exchange rate. However, the effects of domestic-foreign interest rate differential are quite heterogeneous, being in line with theoretical predictions of a standard monetary model for Poland only. According to the decomposition of variance, money supply and interest rates account for 30%-46% of the exchange rate variation in the Czech Republic, from 10% to 14% in Hungary, and from 23% to 42% in Poland.

关键词：捷克共和国匈牙利汇率货币波兰误差修正模型向量自回归型号

Simulation of Heat Transfer and Hydrodynamics over a Free Rotating Disk Using an Improved Radial Velocity Profile

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Journal of Thermal Science 1999年第4期8卷 243-249页

作者： I.V. shevchuk (Institute of Engineering Thermophysics, Ukrainian National Academy of Sciences, 2a, Zhelyabov St., kiev, 03057, Ukraine) Institute of Engineering Thermophysics Ukrainian National Academy of Sciences Kiev Ukraine

The paper presents results of simulation of turbulent heat transfer and hydrodynamics over a free rotating disk using an integral method based on power-law velocity and temperature profiles and three different laws for the tangent of the flow swirl angle tan. It appeared that a quadratic correlation of tan is the most proper one for a free rotating disk. Resulting equation for the Nusselt number is in a better agreement with experimental data of different authors than known Dorfman formula.

关键词：热传导流体力学径向速度剖面

An Exact Solution for Heat Transfer of a Jet Co-Axially Impinging on a Rotating Disk and Its Comparisons with Stagnation Point Experiments

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Journal of Thermal Science 2002年第1期11卷 53-59页

作者： I.V. shevchuk (Institute of Engineering Thermophysics, Ukrainian National Academy of Sciences, 2a, Zhelyabov St., kiev, 03057, Ukraine. E-mail: ivshevch@i.com.ua) Institute of Engineering Thermophysics Ukrainian National Academy of Sciences Ukraine

An exact solution of laminar heat transfer problem for a uniform flow perpendicular to a rotating disk was obtained. Radial velocity at the outer edge of the boundary layer increases linearly in the radial direction, while the temperature difference between the disk and outer flow follows a power law. The problem is solved using self-similar velocity and temperature profiles. Nusselt numbers were computed for the Prandtl numbers Pr=1 and 0.71 at different values of parameters affecting flow and heat transfer. Special flow regime was identified where rotating disk heat transfer is determined only by peculiarities of the impinging flow. Results of predictions agree well with known experiments in the vicinity of the stagnation point.

关键词： impinging jet rotating disk Nusselt number laminar flow heat transfer boundary layer exact solution

To a question on investment attractiveness of regions

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To a question on investment attractiveness of regions

Fore-Body Side Vortex of kVLCC2 at 30°Drift: A Trailing Vortex Resolved with DES and Compared to PIV Data

作者： B.L.Lavrovsky A.I.shevchuk Novosibirsk State Technical University(NSTU) 630092 NovosibirskK.Marks20Russia

This paper compares different opinions on the purposes and nature of the techniques aimed at assessing the investment attractiveness in regions.

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Open Journal of Fluid Dynamics 2019年第4期9卷 303-325页

作者： Dag-Frederik Feder Ivan shevchuk Ahmed Sahab Lukas Gerwers Moustafa Abdel-Maksoud FDS/TUHH Hamburg Germany

A hybrid RANS-LES approach is used to resolve the Fore-body Side Vortex (FSV) separating from the kVLCC2 hull at 30° drift angle and Reynolds number ReLoa ≈ 2.56e6. The performance of the DES approach is evaluated using a proper grid study. Besides, the following aspects of the CFD results are investigated: the resolution of turbulent energy, the prediction of instantaneous and time-averaged vortical structures, local flow features, the limiting streamlines and the evolution of the vortex core flow. New PIV data from wind tunnel experiments is compared to the latter. The results form a basis for future investigations in particular on the vortex interaction further downstream and the applicability of different kinds of turbulence models to trailing vortices like the FSV. Turbulence modelling is realised with the k-ω-SST-IDDES model presented in [1], the grids’ cell count is 6.4 M, 10.5 M and 17.5 M. Grid convergence of the time-averaged vortex core flow is observed. OpenFOAM version 1806 is used to carry out the simulations and snappyHexMesh to build the mesh.

关键词： kVLCC2 DES Hybrid RANS-LES PIV Trailing Vortex Drift

Whirl Interaction of a Drill Bit with the Bore-Hole Bottom

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Modern Mechanical Engineering 2015年第3期5卷 41-60页

作者： Nabil W. Musa V. I. Gulyayev L. V. shevchuk Hasan Aldabas Department of Mechanical Engineering Philadelphia University Amman Jordan Department of Mathematics National Transport University Kyiv Ukraine

This paper deals with the theoretic simulation of a drill bit whirling under conditions of its contact interaction with the bore-hole bottom rock plane. The bit is considered to be an absolutely rigid ellipsoidal body with uneven surface. It is attached to the lower end of a rotating elastic drill string. In the perturbed state, the bit can roll without sliding on the bore-hole bottom, performing whirling vibrations (the model of dynamic equilibrium with pure rolling when maximum cohesive force does not exceed the ultimate Coulombic friction). To describe these motions, a nonholonomic dynamic model is proposed, constitutive partial differential equations are deduced. With their use, the whirling vibrations of oblong and oblate ellipsoidal bits are analyzed, the functions of cohesive (frictional) forces are calculated. It is shown that the system of elastic drill string and ellipsoidal bit can acquire stable or unstable whirl modes with approaching critical Eulerian values by the parameters of axial force, torque and angular velocity. The analogy of the found modes of motions with ones of the Celtic stones is established. It is shown that the ellipsoidal bits can stop their whirling vibrations and change directions of their circumferential motions in the same manner as the ellipsoidal Celtic stones do. As this takes place, the trajectories of the oblate ellipsoidal bits are characterized by more complicated paths and irregularities.

关键词： Deep Drilling Ellipsoidal Bits Nonholonomic Dynamics Celtic Stones Instability Forward and Backward Whirling Motions