The paper starts with a presentation of the versatile leadership model developed by Kaplan and Kaiser and of their 360 feedback tool Leadership Versatility Index (LVI). Versatility can be generally defined as a mast...The paper starts with a presentation of the versatile leadership model developed by Kaplan and Kaiser and of their 360 feedback tool Leadership Versatility Index (LVI). Versatility can be generally defined as a mastery of opposites, as the ability to play multiple roles, even contradictory ones, without emphasizing some at the expense of others. The LVI has been designed to help managers understand their repertoire and how they can become more versatile leaders. It employs an innovative rating scale on which ideal score "0" is in the middle of it (the right amount), flanked by underdoing to the left (too little) and overdoing to the right (too much). The idea is to avoid the "more is better" design trap by providing a way for raters to indicate when managers go to counterproductive extremes. The LVI works with two-sided view of leadership based on two major pairs of opposites: directive vs. supportive leadership and execution vs. strategy. Interventions based on the LVI results help to overcome traditional behaviorism as they combine the outer work (behavioral change) with the inner work (personal change) of development. Application of the LV1 on a sample of the managers from Skoda Auto a.s. and verification of its practical value represented the core of the SAVS IGA project MM/O7/02. The last part of the paper is devoted to a presentation of the findings from this project. The LVI has been found to be both original and a very useful 360 feedback tool which can be addressed to two general groups of clients: (1) experienced senior managers; and (2) young perspective managers in the beginning of their career.展开更多
This paper investigates the flow past two variants of root section profile cascades for a last stage rotor considering three-dimensional flow structures in the near-wall region.Analyses were drawn based on RANS numeri...This paper investigates the flow past two variants of root section profile cascades for a last stage rotor considering three-dimensional flow structures in the near-wall region.Analyses were drawn based on RANS numerical simulations of both variants and on the experimental data obtained by the 3 D traversing in the exit flow field of one of the variants.Extent of 3 D structures at two different regimes and its influence on aerodynamic characteristics of the blade cascades was assessed.The distributions of Mach number along the profiles were compared with 2 D optical measurements and its distortion due to the presence of the sidewall was explored.The interaction between main vortical structures was described and its influence on the loading of the blades,mechanical energy losses and exit flow angle was discussed.The results showed that for a front loaded blade the vortical structures appeared earlier and at a larger extent than for an aft loaded variant.However,due to different Mach number distribution,contribution of end wall flow to the energy losses was lower in the case of the aft loaded variant.The influence of the near wall flow on the loading was found to be rather weak while the deviation of the exit flow angle appeared to be comparable for both of the variants.展开更多
This study presents the comparison of aerodynamic performances of two successive designs of the root profiles for the ultra-long rotor blade equipped with a straight fir-tree dovetail. Since aerodynamic and strength r...This study presents the comparison of aerodynamic performances of two successive designs of the root profiles for the ultra-long rotor blade equipped with a straight fir-tree dovetail. Since aerodynamic and strength requirements laid upon the root section design are contradictory, it is necessary to aerodynamically optimize the design within the limits given by the foremost strength requirements. The most limiting criterion of the static strength is the size of the blade cross-section, which is determined by the number of blades in a rotor and also by the shape and size of a blade dovetail. The aerodynamic design requires mainly the zero incidence angle at the inlet of a profile and in the ideal case ensures that the load does not exceed a limit load condition. Moreover, the typical root profile cascades are transonic with supersonic exit Math number, therefore, the shape of a suction side and a trailing edge has to respect transonic expansion of a working gas. In this paper, the two variants of root section profile cascades are compared and the aerodynamic qualities of both variants are verified using CFD simulation and two mutually independent experimental methods of measurements (optical and pneumatic).展开更多
The contribution deals with the experimental and numerical investigation of compressible flow through the tip-section turbine blade cascade with the blade 54″ long. Experimental investigations by means of optical(int...The contribution deals with the experimental and numerical investigation of compressible flow through the tip-section turbine blade cascade with the blade 54″ long. Experimental investigations by means of optical(interferometry and schlieren method) and pneumatic measurements provide more information about the behaviour and nature of basic phenomena occurring in the profile cascade flow field. The numerical simulation was carried out by means of the EARSM turbulence model according to Hellsten [5] completed by the bypass transition model with the algebraic equation for the intermittency coefficient proposed by Straka and P?íhoda [6] and implemented into the in-house numerical code. The investigation was focused particularly on the effect of shock waves on the shear layer development including the laminar/turbulent transition. Interactions of shock waves with shear layers on both sides of the blade result usually in the transition in attached and/ or separated flow and so to the considerable impact to the flow structure and energy losses in the blade cascade.展开更多
文摘The paper starts with a presentation of the versatile leadership model developed by Kaplan and Kaiser and of their 360 feedback tool Leadership Versatility Index (LVI). Versatility can be generally defined as a mastery of opposites, as the ability to play multiple roles, even contradictory ones, without emphasizing some at the expense of others. The LVI has been designed to help managers understand their repertoire and how they can become more versatile leaders. It employs an innovative rating scale on which ideal score "0" is in the middle of it (the right amount), flanked by underdoing to the left (too little) and overdoing to the right (too much). The idea is to avoid the "more is better" design trap by providing a way for raters to indicate when managers go to counterproductive extremes. The LVI works with two-sided view of leadership based on two major pairs of opposites: directive vs. supportive leadership and execution vs. strategy. Interventions based on the LVI results help to overcome traditional behaviorism as they combine the outer work (behavioral change) with the inner work (personal change) of development. Application of the LV1 on a sample of the managers from Skoda Auto a.s. and verification of its practical value represented the core of the SAVS IGA project MM/O7/02. The last part of the paper is devoted to a presentation of the findings from this project. The LVI has been found to be both original and a very useful 360 feedback tool which can be addressed to two general groups of clients: (1) experienced senior managers; and (2) young perspective managers in the beginning of their career.
基金the Technology Agency of the Czech Republic which supported this research under the grant No.TH02020057The support by the Institute of Thermomechanics of the Czech Academy of Sciences under the internal research funding RVO 61388998the National Grid Infrastructure Meta Centrum provided under the programme“Projects of Large Research,Development,and Innovations Infrastructures”(CESNET LM2015042)。
文摘This paper investigates the flow past two variants of root section profile cascades for a last stage rotor considering three-dimensional flow structures in the near-wall region.Analyses were drawn based on RANS numerical simulations of both variants and on the experimental data obtained by the 3 D traversing in the exit flow field of one of the variants.Extent of 3 D structures at two different regimes and its influence on aerodynamic characteristics of the blade cascades was assessed.The distributions of Mach number along the profiles were compared with 2 D optical measurements and its distortion due to the presence of the sidewall was explored.The interaction between main vortical structures was described and its influence on the loading of the blades,mechanical energy losses and exit flow angle was discussed.The results showed that for a front loaded blade the vortical structures appeared earlier and at a larger extent than for an aft loaded variant.However,due to different Mach number distribution,contribution of end wall flow to the energy losses was lower in the case of the aft loaded variant.The influence of the near wall flow on the loading was found to be rather weak while the deviation of the exit flow angle appeared to be comparable for both of the variants.
基金the Technology Agency of the Czech Republic,which supported this research under grants No.TA03020277 and TH02020057Institutional support RVO61388998
文摘This study presents the comparison of aerodynamic performances of two successive designs of the root profiles for the ultra-long rotor blade equipped with a straight fir-tree dovetail. Since aerodynamic and strength requirements laid upon the root section design are contradictory, it is necessary to aerodynamically optimize the design within the limits given by the foremost strength requirements. The most limiting criterion of the static strength is the size of the blade cross-section, which is determined by the number of blades in a rotor and also by the shape and size of a blade dovetail. The aerodynamic design requires mainly the zero incidence angle at the inlet of a profile and in the ideal case ensures that the load does not exceed a limit load condition. Moreover, the typical root profile cascades are transonic with supersonic exit Math number, therefore, the shape of a suction side and a trailing edge has to respect transonic expansion of a working gas. In this paper, the two variants of root section profile cascades are compared and the aerodynamic qualities of both variants are verified using CFD simulation and two mutually independent experimental methods of measurements (optical and pneumatic).
基金supported by the Technology Agency of the Czech Republic under the grant TA03020277by the Czech Science Foundation under grant P101/12/1271
文摘The contribution deals with the experimental and numerical investigation of compressible flow through the tip-section turbine blade cascade with the blade 54″ long. Experimental investigations by means of optical(interferometry and schlieren method) and pneumatic measurements provide more information about the behaviour and nature of basic phenomena occurring in the profile cascade flow field. The numerical simulation was carried out by means of the EARSM turbulence model according to Hellsten [5] completed by the bypass transition model with the algebraic equation for the intermittency coefficient proposed by Straka and P?íhoda [6] and implemented into the in-house numerical code. The investigation was focused particularly on the effect of shock waves on the shear layer development including the laminar/turbulent transition. Interactions of shock waves with shear layers on both sides of the blade result usually in the transition in attached and/ or separated flow and so to the considerable impact to the flow structure and energy losses in the blade cascade.