Rubbing Phenomena in Rotor-Stator Contact

2000 ◽  
Author(s):  
Z. C. Feng ◽  
Xiao-Zhang Zhang
Keyword(s):  
Steady State ◽  
Radial Velocity ◽  
Analytical Model ◽  
Contact Surface ◽  
Initial Perturbation ◽  
Instantaneous Change

Abstract This paper discusses the vibration phenomena of a rotor rubbing with a stator caused by an initial perturbation. The analytical model consists of a simple disc-shaft rotor and a fixed stator. The perturbation is an instantaneous change of the radial velocity when the rotor is rotating in its normal steady state. It is found that under certain conditions, the rotor will remain rubbing with the stator, even if the initial perturbation no longer exists. In the case of no friction on the contact surface between the rotor and the stator, the full rubbing behaves as forward whirling. When friction is present, the full rubbing behaves as backward whirling.

Simulation of the Steady-State Photocarrier Grating Method Applied to Amorphous Materials

1992 ◽  
Vol 258 ◽  
Author(s):  
C.-D. Abel ◽  
G. H. Bauer
Keyword(s):  
Numerical Simulation ◽  
Steady State ◽  
Electric Field ◽  
Closed Form ◽  
Analytical Model ◽  
Amorphous Materials ◽  
Grating Period ◽  
Amorphous Semiconductors ◽  
Closed Form Expression ◽  
Form Expression

ABSTRACTGeneral features of the steady-state photocarrier grating technique applied to amorphous semiconductors are investigated by complete numerical simulation. The results are interpreted with an analytical model which delivers a closed-form expression for β(A,E) assuming dominance of one carrier type. The variation of the electric field E instead of the grating period A is suggested as an easier and more accurate tool for the experimental technique.

scholarly journals A 2.5-D electron Hall-MHD analytical model of steady state Hall magnetic reconnection in a compressible plasma

2011 ◽  
Vol 116 (A5) ◽  
Author(s):  
D. B. Korovinskiy ◽  
V. S. Semenov ◽  
N. V. Erkaev ◽  
A. V. Divin ◽  
H. K. Biernat ◽  
...  
Keyword(s):  
Steady State ◽  
Magnetic Reconnection ◽  
Analytical Model ◽  
Compressible Plasma ◽  
Hall Mhd

scholarly journals Analytical model of hybrid MMC for dynamic and steady-state studies

2017 ◽  
Vol 2017 (13) ◽  
pp. 2281-2286
Author(s):  
Xiaojun Lu ◽  
Wang Xiang ◽  
Weixing Lin ◽  
Jinyu Wen
Keyword(s):  
Steady State ◽  
Analytical Model

scholarly journals Large and irreversible future decline of the Greenland ice-sheet

2020 ◽  
Author(s):  
Jonathan M. Gregory ◽  
Steven E. George ◽  
Robin S. Smith
Keyword(s):  
Climate Change ◽  
Steady State ◽  
Sea Level ◽  
General Circulation ◽  
Initial Perturbation ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Circulation Model ◽  
Intergovernmental Panel ◽  
Recent Climate

Abstract. We have studied the evolution of the Greenland ice-sheet under a range of constant climates typical of those projected for the end of the present century, using a dynamical ice-sheet model (Glimmer) coupled to an atmospheric general circulation model (FAMOUS-ice AGCM). The ice-sheet surface mass balance (SMB) is simulated by the AGCM, including its dependence on altitude within AGCM gridboxes. Over millennia under a warmer climate, the ice-sheet reaches a new steady state, whose mass is correlated with the initial perturbation in SMB, and hence with the magnitude of global climate change imposed. For the largest global warming considered (about +5 K), the contribution to global-mean sea-level rise (GMSLR) is initially 2.7 mm yr−1, and the ice-sheet is eventually practically eliminated (giving over 7 m of GMSLR). For all RCP8.5 climates, final GMSLR exceeds 4 m. If recent climate were maintained, GMSLR would reach 1.5–2.5 m. Contrary to expectation from earlier work, we find no evidence for a threshold warming that divides scenarios in which the ice-sheet suffers little reduction from those which it is mostly lost. This is because the dominant effect is reduction of area, not reduction of surface altitude, and the geographical variation of SMB must be taken into account. The final steady state is achieved by withdrawal from the coast in some places, and a tendency for increasing SMB due to enhancement of cloudiness and snowfall over the remaining ice-sheet, through the effects of topographic change on atmospheric circulation. If late twentieth-century climate is restored, the ice-sheet will not regrow to its present extent, owing to such effects, once its mass has fallen below a threshold of about 4 m of sea-level equivalent. In that case, about 2 m of GMSLR would become irreversible. In order to avoid this outcome, anthropogenic climate change must be reversed before the ice-sheet has declined to the threshold mass, which would be reached in about 600 years at the highest rate of mass-loss within the likely range of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.

Two-dimensional steady-state thermal analytical model of permanent-magnet synchronous machines operating in generator mode

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zakarya Djelloul Khedda ◽  
Kamel Boughrara ◽  
Frédéric Dubas ◽  
Baocheng Guo ◽  
El Hadj Ailam
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Permanent Magnet ◽  
Analytical Model ◽  
Electrical Machines ◽  
Synchronous Machines ◽  
Analytical Prediction ◽  
Two Dimensional ◽  
Content Type ◽  
Proposed Model

Purpose Thermal analysis of electrical machines is usually performed by using numerical methods or lumped parameter thermal networks depending on the desired accuracy. The analytical prediction of temperature distribution based on the formal resolution of thermal partial differential equations (PDEs) by the harmonic modeling technique (or the Fourier method) is uncommon in electrical machines. Therefore, this paper aims to present a two-dimensional (2D) analytical model of steady-state temperature distribution for permanent-magnet (PM) synchronous machines (PMSM) operating in generator mode. Design/methodology/approach The proposed model is based on the multi-layer models with the convolution theorem (i.e. Cauchy’s product theorem) by using complex Fourier’s series and the separation of variables method. This technique takes into the different thermal conductivities of the machine parts. The heat sources are determined by calculating the different power losses in the PMSM with the finite-element method (FEM). Findings To validate the proposed analytical model, the analytical results are compared with those obtained by thermal FEM. The comparisons show good results of the proposed model. Originality/value A new 2D analytical model based on the PDE in steady-state for full prediction of temperature distribution in the PMSM takes into account the heat transfer by conduction, convection and radiation.

An analytical model for simulating steady state flows of downburst

2013 ◽  
Vol 115 ◽  
pp. 53-64 ◽  
Author(s):  
El-Sayed Abd-Elaal ◽  
Julie E. Mills ◽  
Xing Ma
Keyword(s):  
Steady State ◽  
Analytical Model

Novel, Gasketless, Interconnect Using Parallel Superhydrophobic Surfaces for Modular Microfluidic Systems

2011 ◽  
Author(s):  
Christopher R. Brown ◽  
Bahador Farshchian ◽  
Pin-Chuan Chen ◽  
Taehyun Park ◽  
Sunggook Park ◽  
...  
Keyword(s):  
Steady State ◽  
Analytical Model ◽  
Liquid Bridge ◽  
Contact Angles ◽  
Superhydrophobic Surfaces ◽  
Maximum Pressure ◽  
The Novel ◽  
Microfluidic Systems ◽  
Order Of Magnitude ◽  
State Pressure

A novel, modular, microfluidic interconnect was developed using parallel superhydrophobic interfaces to facilitate the transport of fluids between component chips in modular microfluidic systems. A static analytical model, derived from the Laplace equation [1], approximates the maximum steady-state pressure of the liquid at the liquid bridge which forms across the gap between the chips. Preliminary experiments using parallel superhydrophobic surfaces on PMMA validated the concept. Additional experiments controlled the gap distance, measured contact angles of the superhydrophobic surfaces, gradually increased the pressure of the novel, gasketless, interconnect until rupture to find the maximum pressure across the liquid bridge and verify the model. The measured pressures were on the same order of magnitude (1–10 kPa) as estimated using the model for gap distances of 25 μm and 100 μm.

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