1-2/2010

Contents:

• A.Ambroziak, P.Klosowski, Example of Tension Fabric Structure Analysis - abstract | full text
• J.Swirydczuk, Secondary Flow Structures and Resultant Exit Flow Angle Fluctuations in High Pressure Steam Turbine Stage - abstract | full text
• S.B.Leble, D.V.Ponomarev, Dressing of Zero-Range Potentials into Realistic Molecular Potentials of Finite Range - abstract | full text
• M.Rychcik-Leyk, M.Bialoskorski, J.Dziedzic, J.Rybicki, MD Simulations of Ultraprecision Machining of fcc Monocrystals - abstract | full text

Abstracts:

• A.Ambroziak, P.Klosowski, Example of Tension Fabric Structure Analysis

  The aim of this work is to examine two variants of non-linear strain-stress relations accepted for a description of the architectural fabric. A discussion on the fundamental equations of the dense net model used in the description of the coated woven fabric behaviour is presented. An analysis of tensile fabric structures subjected to dead load and initial pretension is described.

• J.Swirydczuk, Secondary Flow Structures and Resultant Exit Flow Angle Fluctuations in High Pressure Steam Turbine Stage

  The object of investigation is the stage, the geometry and flow conditions of which are typical for a series of steam turbines in operation in Polish power plants. The flow analysis is based on the CFD calculations performed using FlowER, a specialized URANS code developed for studying unsteady phenomena in turbine stages and sections. The paper presents flow patterns illustrating the interaction between vortices inside and downstream of the rotor passage and the resultant exit flow angle (EFA) fluctuations recorded at the stage exit. An attempt is made to attribute individual EFA fluctuations to particular vortices and their development stages.

• S.B.Leble, D.V.Ponomarev, Dressing of Zero-Range Potentials into Realistic Molecular Potentials of Finite Range

  The zero-range potentials of the radial Schrodinger equation and their dressing are investigated. A sequence of Darboux transformations involving a set of parameters yields solvable potentials of a finite-range with physically meaningful properties. In particular, the newly obtained potential is matched to that resulting from the ab initio computation methods in terms of discrete and continuous spectrum parameters. The approach, being a companion to conventional quantum simulation methods, combines symbolical and numerical calculations and is expected to work best for molecules with high spherical symmetry, typically fullerenes.

• M.Rychcik-Leyk, M.Bialoskorski, J.Dziedzic, J.Rybicki, MD Simulations of Ultraprecision Machining of fcc Monocrystals

  In technical sciences, the term "machining" refers to the process of forming an object into a desired shape and size, with a desired quality of surface, by removing layers of its material by means of a cutting tool. The paper describes research on ultra-precision machining (UPM), where the abovementioned process takes place on the atomic level and involves systems (a machined object and a tool) several dozen nanometers in size. Three-dimensional computer simulations (virtual experiments) of UPM of monocrystalline copper with an infinitely hard tool were performed utilizing the classical molecular dynamics (MD) method with a many-body potential to describe the interatomic interactions. Among the examined issues were: the effect of the tool shape, machining speed and depth on the obtained workmaterial surfaces, and on the stresses, slip patterns and local temperature increases generated during the process.