Relevant bibliographies by topics / Non-steady state condition

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Non-steady state condition'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Non-steady state condition.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Non-steady state condition"

1

Madžar, Dominik, Christian Maihöfner, Rüdiger Zimmermann, Stefan Schwab, Johannes Kornhuber, and Piotr Lewczuk. "Cerebrospinal fluid under non-steady state condition caused by plasmapheresis." Journal of Neural Transmission 118, no. 2 (November 16, 2010): 219–22. http://dx.doi.org/10.1007/s00702-010-0519-z.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Przekop, Rafał, and Leon Gradoń. "Non-steady-state aerosol filtration in nanostructured fibrous media." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 369, no. 1945 (June 28, 2011): 2476–84. http://dx.doi.org/10.1098/rsta.2011.0063.

Full text
Abstract:
The filtration of aerosol particles using composites of nano- and microsized fibrous structures is a promising method for the effective separation of nanoparticles from gases. A multi-scale physical system describing the flow pattern and particle deposition at a non-steady-state condition requires an advanced method of modelling. The combination of lattice Boltzmann and Brownian dynamics was used for analysis of the particle deposition pattern in a fibrous system. The dendritic structures of deposits for neutral and charged fibres and particles are present. The efficiency of deposition, deposit morphology, porosity and fractal dimension were calculated for a selected operational condition of the process.
APA, Harvard, Vancouver, ISO, and other styles
3

Abidat, M., M. Hachemi, M. K. Hamidou, and N. C. Baines. "Prediction of the steady and non-steady flow performance of a highly loaded mixed flow turbine." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 212, no. 3 (May 1, 1998): 173–84. http://dx.doi.org/10.1243/0957650981536844.

Full text
Abstract:
This paper describes a method for predicting the performance under both turbine inlet steady state and non-steady state flow conditions of a mixed flow turbine used for turbocharged internal combustion engines. The mixed flow turbine steady state performances computed with the steady state performance prediction method are in good agreement with the experimental results obtained in the Imperial College turbocompressor cold air test rig. The unsteady state performance is computed using a one-dimensional model based on the solution of the unsteady one-dimensional flow equations. These equations are solved in the volute by a finite difference method using a four-step explicit Runge—Kutta scheme. The instantaneous volute exit condition is provided by the steady state rotor performance prediction model with the assumption of a quasi-steady state flow in the rotor. The computed instantaneous performances are in reasonable agreement with published experimental data for the same mixed flow turbine. The unsteady flow model is also used to study the effects of the frequency and the amplitude of the pulse on the performances of the mixed flow turbine.
APA, Harvard, Vancouver, ISO, and other styles
4

Sudi Mungkasi. "Modelling And Simulation of Topical Drug Diffusion in The Dermal Layer of Human Body." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 86, no. 2 (August 24, 2021): 39–49. http://dx.doi.org/10.37934/arfmts.86.2.3949.

Full text
Abstract:
We consider the problem of drug diffusion in the dermal layer of human body. Two existing mathematical models of the drug diffusion problem are recalled. We obtain that the existing models lead to inconsistent equations for the steady state condition. We also obtain that solutions to the existing models are unrealistic for some cases of the unsteady state condition, because negative drug concentrations occur due to the inappropriate assumption of the model. Therefore, in this paper, we propose a modified mathematical model, so that the model is consistent, and the solution is nonnegative for both steady and unsteady state conditions of the drug diffusion problem in the dermal layer of human body. For the steady state condition, the exact solution to the proposed model is given. For unsteady state condition, we use a finite difference method for solving the models numerically, where the discretisation is centred in space and forward in time. Simulation results confirm that our proposed model and method preserve the non-negativity of the solution to the problem, so the solution is more realistic than that of the old model.
APA, Harvard, Vancouver, ISO, and other styles
5

Radrizzani, Danilo, Riccardo Giudici, Barbara DeToffol, Simone Fracassi, Matteo Lucchelli, Giorgio Musazzi, Luisa Santambrogio, and Cristian Leva. "Evaluation of oxygen consumption and energy expenditure after cardiac surgery in non-steady-state condition." Nutritional Therapy & Metabolism 31, no. 1 (December 20, 2012): 45–51. http://dx.doi.org/10.5301/ntm.2012.10447.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Tuvdendorj, Demidmaa, David L. Chinkes, David N. Herndon, Xiao-Jun Zhang, and Robert R. Wolfe. "A novel stable isotope tracer method to measure muscle protein fractional breakdown rate during a physiological non-steady-state condition." American Journal of Physiology-Endocrinology and Metabolism 304, no. 6 (March 15, 2013): E623—E630. http://dx.doi.org/10.1152/ajpendo.00552.2012.

Full text
Abstract:
The measurement of the fractional breakdown rate (FBR) of muscle proteins during physiological non-steady state of amino acids (AAs) presents some challenges. Therefore, the goal of the present experiment was to modify the bolus stable isotope tracer injection approach to determine both fractional synthesis rate (FSR) and FBR of leg muscle protein during a physiological non-steady state of AAs. The approach uses the traditional precursor-product principle but is modified with the assumption that inward transport of AAs is proportional to their plasma concentrations. The FBR value calculated from the threonine tracer served as a reference to evaluate the validity of the FBR measurement from the phenylalanine tracer, which was under a non-steady-state condition due to the concomitant injection of unlabeled phenylalanine. Plasma phenylalanine concentration increased more than fourfold after the bolus injection, and thereafter it decreased exponentially, whereas the threonine concentration remained stable. FBR values were similar with the two tracers [0.133 ± 0.003 and 0.148 ± 0.003%/h (means ± SE) for the phenylalanine and threonine tracers, respectively, P > 0.05]. In addition, FSR values for the two tracers were similar (0.069 ± 0.002 and 0.067 ± 0.001%/h for the phenylalanine and threonine tracers, respectively, P > 0.05), indicating that the traditional FSR approach can also be used in the non-steady state. Accordingly, net balance (NB) values were similar (−0.065 ± 0.002 and −0.081 ± 0.002%/h for the phenylalanine and threonine tracers, respectively, P > 0.05). This new method of measuring muscle protein FBR during physiological non-steady state gives reliable results and allows simultaneous measurement of muscle protein FSR and thus a calculation of NB.
APA, Harvard, Vancouver, ISO, and other styles
7

Pumo, D., F. Viola, and L. V. Noto. "Ecohydrology in Mediterranean areas: a numerical model to describe growing seasons out of phase with precipitations." Hydrology and Earth System Sciences 12, no. 1 (February 27, 2008): 303–16. http://dx.doi.org/10.5194/hess-12-303-2008.

Full text
Abstract:
Abstract. The probabilistic description of soil moisture dynamics is a relatively new topic in hydrology. The most common ecohydrological models start from a stochastic differential equation describing the soil water balance, where the unknown quantity, the soil moisture, depends both on spaces and time. Most of the solutions existing in literature are obtained in a probabilistic framework and under steady-state condition; even if this last condition allows the analytical handling of the problem, it has considerably simplified the same problem by subtracting generalities from it. The steady-state hypothesis, appears perfectly applicable in arid and semiarid climatic areas like those of African's or middle American's savannas, but it seems to be no more valid in areas with Mediterranean climate, where, notoriously, the wet season foregoes the growing season, recharging water into the soil. This moisture stored at the beginning of the growing season (known as soil moisture initial condition) has a great importance, especially for deep-rooted vegetation, by enabling survival in absence of rainfalls during the growing season and, however, keeping the water stress low during the first period of the same season. The aim of this paper is to analyze the soil moisture dynamics using a simple non-steady numerical ecohydrological model. The numerical model here proposed is able to reproduce soil moisture probability density function, obtained analytically in previous studies for different climates and soils in steady-state conditions; consequently it can be used to compute both the soil moisture time-profile and the vegetation static water stress time-profile in non-steady conditions. Here the differences between the steady-analytical and the non-steady numerical probability density functions are analyzed, showing how the proposed numerical model is able to capture the effects of winter recharge on the soil moisture. The dynamic water stress is also numerically evaluated, implicitly taking into account the soil moisture condition at the beginning of the growing season. It is also shown the role of different annual climatic parameterizations on the soil moisture probability density function and on the vegetation water stress evaluation. The proposed model is applied to a case study characteristic of Mediterranean climate: the watershed of Eleuterio in Sicily (Italy).
APA, Harvard, Vancouver, ISO, and other styles
8

Higashimori, Mitsuo, Kiyoshi Yamaoka, and Terumichi Nakagawa. "Dose‐Dependency in Local Disposition of 5‐Fluorouracil under Non‐Steady‐State Condition in Rat Liver." Journal of Pharmaceutical Sciences 89, no. 1 (January 2000): 100–107. http://dx.doi.org/10.1002/(sici)1520-6017(200001)89:1<100::aid-jps10>3.0.co;2-l.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Higashimori, Mitsuo, Kiyoshi Yamaoka, and Terumichi Nakagawa. "Dose-dependency in local disposition of 5-fluorouracil under non-steady-state condition in rat liver." Journal of Pharmaceutical Sciences 89, no. 1 (January 2000): 100. http://dx.doi.org/10.1002/(sici)1520-6017(200001)89:1<100::aid-jps10>3.3.co;2-c.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Venturini, Elisa, Ivano Vassura, Cristian Zanetti, Andrea Pizzi, Giuseppe Toscano, and Fabrizio Passarini. "Evaluation of non-steady state condition contribution to the total emissions of residential wood pellet stove." Energy 88 (August 2015): 650–57. http://dx.doi.org/10.1016/j.energy.2015.05.105.

Full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "Non-steady state condition"

1

Zimmerman, Martin. "Chování EHD mazacího filmu při náhlých změnách rychlosti a zatížení." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-233979.

Full text
Abstract:
This dissertation is focused on experimental study of lubricant film behavior under transient conditions. For real machine parts such as gears, roller bearings and cam mechanism the operating conditions such as speed, load and radius of curvature of rubbing surfaces are vary during the working cycle. Change in operating conditions may pose an increased risk of the lubricating film breakdown. Direct contact of rubbing surfaces at the time of the lubricating film breakdown causes an increase in friction and wear. The high-speed CMOS camera was used to record the dynamic changes in lubricating film thickness during the experiment. The optical interferometry method has been used for reverse reconstruction of lubricating film thickness of the recorded interferograms. It was confirmed that the operating parameters have a major impact on the formation of lubricant film and its thickness and a certain combination of boundary conditions can cause lubricating film rupture. The obtained results showed, that modified topography of the rubbing surfaces can help to increase the lubrication film thickness especially in critical phases of working cycle.
APA, Harvard, Vancouver, ISO, and other styles
2

Ahmed, Kamel Abd El-Salam Attia. "Automobile cornering behaviour under steady and non-steady state conditions." Thesis, University of Leeds, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329475.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Nguyen, Vinh Q. "A Numerical Study of Burgers' Equation With Robin Boundary Conditions." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/31285.

Full text
Abstract:
This thesis examines the numerical solution to Burgers' equation on a finite spatial domain with various boundary conditions. We first conduct experiments to confirm the numerical solutions observed by other researchers for Neumann boundary conditions. Then we consider the case where the non-homogeneous Robin boundary conditions approach non-homogeneous Neumann conditions. Finally we numerically approximate the steady state solutions to Burgers' equation with both the homogeneous and non-homogeneous Robin boundary conditions.
Master of Science
APA, Harvard, Vancouver, ISO, and other styles
4

Anderson, Mark Jule Jr. "Cooperative Behavior in Driven Lattice Systems with Shifted Periodic Boundary Conditions." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/30606.

Full text
Abstract:
We explore the nature of driven stochastic lattice systems with non-periodic boundary conditions. The systems consist of particle and holes which move by exchanges of nearest neighbor particle-hole pairs. These exchanges are controlled by the energetics associated with an internal Hamiltonian, an external drive and a stochastic coupling to a heat reservoir. The effect of the drive is to bias particle-hole exchanges along the field in such a way that a particle current can be established. Hard-core volume constraints limit the occupation of only one particle (hole) per lattice site. For certain regimes of the overall particle density and temperature, a system displays a homogeneous disordered phase. We investigate cooperative behavior in this phase by using two-point spatial correlation functions and structure factors. By varying the particle density and the temperature, the system orders into a phase separated state, consisting of particle-rich and particle-poor regions. The temperature and density for the co-existence state depend on the boundary conditions. By using Monte Carlo simulations, we establish co-existence curves for systems with shifted periodic boundary conditions.
Ph. D.
APA, Harvard, Vancouver, ISO, and other styles
5

Leroudier, Julien. "Croissance rapide en solution de cristaux pour l'optique non linéaire quadratique." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00626529.

Full text
Abstract:
La croissance cristalline de KH2PO4(KDP)and K(H1-xDx)2PO4(DKDP)a été fortement étudiée depuis de nombreuses années. Les propriétés optiques nonlinéaires (conversion de fréquence: doublage pour le KDP et triplage pour le DKDP)et les études fondamentales sur les mécanismes de croissance sont à la base du développement important de la croissance de ces cristaux. Au début des années 90, un fort intérêt s'est porté sur le KDP et DKDP pour les dispositifs optiques à large ouverture pour les applications industrielles de fusion inertielle comme au NAtional Ignition Facility (NIF) aux USA ou pour le laser MégaJoule en France. La dimension de ces optiques (40*40 cm²) nécessite des cristaux géants crûs en solution. Une technique de croissance rapide a été développé par abaissement de température dans un réacteur de 1000L et par une filtration en continu afin d'éviter la nucléation spontanée. Cette méthode est très robuste et fiable pour la croissance rapide de cristaux géants de KDP mais néanmoins montre des limitations inhérentes à cette méthode. En effet, cela mène à des cristaux inhomogènes (défauts, inhomogénéités isotopiques)ce qui est rédhibitoire pour des solutions solides intermédiaires comme le DKDP : la composition en début de croissance peut varier significativement de celle en fin de croissance. Très récemment, des méthodes par circulation de solution en conditions stationnaires ont été développées pour palier à ce problèmeet sont considérées comme les plus pertinentes. C'est pourquoi nous avons développé un système par circulation en conditions stationnaires avec un traitement original de la solution. Dans un premier temps, le système a été testé sur un composé modèle KDP puis dans un deuxième sur le composé utilisé pour l'application DKDP.
APA, Harvard, Vancouver, ISO, and other styles
6

Abbas, Qaisar. "Weak Boundary and Interface Procedures for Wave and Flow Problems." Doctoral thesis, Uppsala universitet, Avdelningen för teknisk databehandling, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-159440.

Full text
Abstract:
In this thesis, we have analyzed the accuracy and stability aspects of weak boundary and interface conditions (WBCs) for high order finite difference methods on Summations-By-Parts (SBP) form. The numerical technique has been applied to wave propagation and flow problems. The advantage of WBCs over strong boundary conditions is that stability of the numerical scheme can be proven. The boundary procedures in the advection-diffusion equation for a boundary layer problem is analyzed. By performing Navier-Stokes calculations, it is shown that most of the conclusions from the model problem carries over to the fully nonlinear case. The work was complemented to include the new idea of using WBCs on multiple grid points in a region, where the data is known, instead of at a single point. It was shown that we can achieve high accuracy, an increased rate of convergence to steady-state and non-reflecting boundary conditions by using this approach. Using the SBP technique and WBCs, we have worked out how to construct conservative and energy stable hybrid schemes for shocks using two different approaches. In the first method, we combine a high order finite difference scheme with a second order MUSCL scheme. In the second method, a procedure to locally change the order of accuracy of the finite difference schemes is developed. The main purpose is to obtain a higher order accurate scheme in smooth regions and a low order non-oscillatory scheme in the vicinity of shocks. Furthermore, we have analyzed the energy stability of the MUSCL scheme, by reformulating the scheme in the framework of SBP and artificial dissipation operators. It was found that many of the standard slope limiters in the MUSCL scheme do not lead to a negative semi-definite dissipation matrix, as required to get pointwise stability. Finally, high order simulations of shock diffracting over a convex wall with two facets were performed. The numerical study is done for a range of Reynolds numbers. By monitoring the velocities at the solid wall, it was shown that the computations were resolved in the boundary layer. Schlieren images from the computational results were obtained which displayed new interesting flow features.
APA, Harvard, Vancouver, ISO, and other styles
7

Frýza, Josef. "Elastohydrodynamic Film Study under Impact Loading and Lateral Vibrations." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-371778.

Full text
Abstract:
Disertační práce se zabývá chováním a odezvou elastohydrodynamického (EHD) mazacího filmu za neustálených provozních podmínek. V úvodní části práce jsou shrnuty poznatky z oblasti EHD mazání; od jeho historie, přes základní mechanismy mazání a používané experimentální metody, až po nedávno publikované studie zaměřené na transientní podmínky. Hlavním cílem práce bylo experimentálně objasnit vliv provozních parametrů a reologických vlastností maziv na chování mazacího filmu v bodovém kontaktu při jeho nárazovém zatěžování a vystavení příčným vibracím. Za tímto účelem byla vyvinuta laboratorní zařízení umožňující měření rozložení mazacího filmu a tření za kontrolovaných nestacionárních podmínek. Experimenty odhalili zásadní roli přibližovacích a zatěžovacích rychlostí na formování stlačených mazacích filmů při nárazovém zatěžování. Výsledky byly srovnávány s nedávným teoretickým řešením. Bylo ukázáno na jeho nedostatky, jež byly následně odstraněny implementací empirických vztahů zohledňujících reologii maziv. V případě příčných vibrací byly nalezeny hranice selhání mazacího filmu a určeny vztahy popisující vliv příčných vibrací na centrální tloušťku filmu a její fluktuace jednotně pro všechny maziva. Závěrečná část práce poskytuje nový pohled na reologii maziv pomocí inovativního přístupu měření třecích reakcí maziva současně ve dvou směrech kontaktu za podmínek příčných vibrací. Tyto původní výsledky rozšiřují pochopení mechanizmů EHD mazání a mohou být použity k dokonalejším návrhům strojů, a vylepšit tak jejich účinnost, spolehlivost a životnost.
APA, Harvard, Vancouver, ISO, and other styles

Books on the topic "Non-steady state condition"

1

Ingestad, Torsten. Data base for birch plants at steady-state: Performance of birch plants (Betula pendula Roth.) under non-limiting conditions and under limitation by nitrogen and light. Uppsala: Institutionen för ekologi och miljövård, Sveriges lantbruksuniversitet, 1994.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
2

Ingestad, Torsten. Data base for tomato plants at steady-state: Methods and performance of tomato plants (Lycopersicon esculentum Mill. cv. Solentos) under non-limiting conditions and under limitation by nitrogen and light. Uppsala: Institutionen för ekologi och miljövård, Sveriges lantbruksuniversitet, 1994.

Find full text
APA, Harvard, Vancouver, ISO, and other styles

Book chapters on the topic "Non-steady state condition"

1

Mauro, Raffaele. "Waiting Phenomena at Steady State and Non-steady State Conditions." In Calculation of Roundabouts, 59–105. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-04551-6_3.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Harris, Graham P. "Physiological scales: non-steady state conditions in the field." In Phytoplankton Ecology, 166–92. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-3165-7_8.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Harris, Graham P. "Physiological scales: non-steady state conditions in the field." In Phytoplankton Ecology, 166–92. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4081-9_8.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Meira Castro, Ana C., J. Matos, and A. Gavina. "Numerical Solution of a PDE System with Non-Linear Steady State Conditions that Translates the Air Stripping Pollutants Removal." In Nonlinear Science and Complexity, 211–19. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-90-481-9884-9_26.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Selvam A., George Maria, and Janagaraj R. "Bifurcation and Chaos in a Discrete Fractional-Order Prey-Predator System Involving Allee Effect." In Advanced Applications of Fractional Differential Operators to Science and Technology, 21–40. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-3122-8.ch002.

Full text
Abstract:
This chapter considers the discrete counterpart of a fractional order prey-predator ODE system involving Allee effect. Several more realistic models were proposed to describe nonlinear interactions between species by introducing different types functional responses and Allee effect. Non-local property of fractional differential equations is useful in modeling population interactions possessing memories. The model under investigation has three steady states, and the positive steady state exists under certain condition. Dynamic nature of the model is discussed through local stability analysis. Enquiry into the qualitative behavior of the model reveals rich and complex dynamics exhibited by the discrete-time model. Moreover, this model undergoes Neimark Sacker bifurcation when the chosen parameter passes through a critical value. The analytical results are strengthened with appropriate numerical examples. The computation of maximal Lyapunov exponents confirms the existence of chaos. Chaos control is achieved by linear feedback control and hybrid control methods.
APA, Harvard, Vancouver, ISO, and other styles
6

Maurya, Rakesh Kumar, and Akhil Nekkanti. "Combustion Instability Analysis Using Wavelets in Conventional Diesel Engine." In Mathematical Concepts and Applications in Mechanical Engineering and Mechatronics, 390–413. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-1639-2.ch019.

Full text
Abstract:
Combustion instability affects the drivability, power, engine performance and efficiency. Elimination of combustion instabilities leads to increase in power for the same fuel economy. Effective controller can reduce combustion instabilities by understanding patterns in the cyclic variations. In this study, cyclic variations of combustion parameters were analyzed in a diesel engine using wavelet analysis. The experiments were conducted at varying loads and compression ratios at 1500 rpm. At steady state condition, cylinder pressure data of 2000 consecutive combustion cycles was measured. Continuous Wavelet Transform was used to capture non-stationary or transient features that might not have been detected using other transforms. Wavelet Power Spectrum (WPS) and Global Wavelet Spectrum were further used to determine the relationship between fluctuations in combustion parameters. Contour Plots were plotted based on WPS for visualizing the intensity and frequency of cyclic Variations. It was found that cyclic variability decreases with increase in engine load and compression ratio.
APA, Harvard, Vancouver, ISO, and other styles
7

Sugimura, J., and H. A. Spikes. "Technique for measuring EHD film thickness in non-steady state contact conditions." In Elastohydrodynamics - '96 Fundamentals and Applications in Lubrication and Traction, Proceedings of the 23rd Leeds-Lyon Symposium on Tribology held in the Institute of Tribology, Department of Mechanical Engineering, 91–100. Elsevier, 1997. http://dx.doi.org/10.1016/s0167-8922(08)70439-5.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

"Chapter 9 Ammonia, Methanol and Sulphur Production Under Non-Steady-State Conditions." In Studies in Surface Science and Catalysis, 347–89. Elsevier, 1989. http://dx.doi.org/10.1016/s0167-2991(09)61268-4.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Bibik, Olena, and Oleksandr Popovich. "INCREASING THE EFFICIENCY OF ELECTRIC DRIVES WITH PERIODICAL LOADING BY USING COMPREHENSIVE MATHEMATICAL MODELING MEANS." In Priority areas for development of scientific research: domestic and foreign experience. Publishing House “Baltija Publishing”, 2021. http://dx.doi.org/10.30525/978-9934-26-049-0-31.

Full text
Abstract:
The mode of operation of induction motors (IMs) affects their performance. In most cases, motors are optimally designed for steady state operation. When operating in other modes, additional attention is required to the problems of energy efficiency. Induction motors are the most common type of electromechanical energy converters, and a significant part of them operate under conditions of periodic changes in the load torque. The work is devoted to solving the problem of increasing the energy efficiency of asynchronous motors of electromechanical systems with a periodic load, including pumping and compressor equipment. The traditional solution to this problem for compressor equipment is the optimal design of an IM under static conditions, as well as the use of flywheels, the use of an IM with an increased slip value and controlled IM with a squirrel-cage rotor and with frequency converters. In this work, the modes of operation of asynchronous motors with periodic loading are investigated. For this, complex mathematical models are developed in the simulation system. Such models are effective in modeling taking into account periodic load changes: repetitive transient processes, their possible asymmetry and non-sinusoidality, increased influence of nonlinearity of electromagnetic parameters. In complex mathematical modeling, the mutual influence of the constituent parts of the electromechanical system is taken into account. Simulation allowed quantifying the deterioration in energy efficiency under intermittent loading, in comparison with static modes. Criteria for evaluating quasi-static modes have been developed and areas of critical decrease in efficiency have been determined. The paper proposes and demonstrates a methodology for solving this problem. For this purpose, tools have been created for the optimal design of asynchronous motors as part of electromechanical systems with periodic loading. These tools include: complex mathematical models of electromechanical systems with asynchronous motors with periodic load, mathematical tools for determining the parameters of quasi-steady-state modes, the methodology of optimal design based on the criterion of the maximum efficiency of processes under quasi-steady-state modes of operation. The possibilities, advantages and prospects of using the developed mathemati-cal apparatus for solving a number of problems to improve the efficiency of electric drives of compressor and pumping equipment are demonstrated. It is shown that by taking into account quasi-static processes, the use of complex mathematical models for the optimal design of asynchronous motors with a periodic load provides an in-crease in efficiency up to 8 ... 10%, relative to the indicators of motors that are de-signed without taking into account the quasi-static modes. The areas of intense quasi-steady-state modes are determined using the devel-oped criterion. In these areas, there is a critical decrease in efficiency compared to continuous load operation. A decrease in efficiency is associated with a decrease in the amount of kinetic energy of the rotating parts compared to the amount of electromagnetic energy. In connection with the development of a frequency-controlled asynchronous drive of mechanisms with a periodic load, the relevance of design taking into account the peculiarities of quasi-static has increased significantly. For example, a variable frequency drive of a refrigerator compressor or a heat pump can increase energy efficiency up to 40%, but at low speeds, due to a decrease in kinetic energy, the efficiency can decrease to 10 ... 15%, unless a special design methodology is applied. This problem can be solved by using the complex mathematical modeling tools developed in the article.
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "Non-steady state condition"

1

Anker, Jan, Birte Schrader, Udo Seybold, Jürgen Mayer, and Michael Casey. "A Three-dimensional Non-reflecting Boundary Condition Treatment for Steady-state Flow Simulations." In 44th AIAA Aerospace Sciences Meeting and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2006. http://dx.doi.org/10.2514/6.2006-1275.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Ippolito, Corey A., Nhan T. Nguyen, Joseph Totah, Khanh Trinh, and Eric B. Ting. "Initial Assessment of a Variable-Camber Continuous Trailing-Edge Flap System for Drag-Reduction of Non-Flexible Aircraft in Steady-State Cruise Condition." In AIAA Infotech@Aerospace (I@A) Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2013. http://dx.doi.org/10.2514/6.2013-5143.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Gisbert, Fernando, and Roque Corral. "A Novel Mixing Plane Method Using Non-Reflecting Boundary Conditions for Multi-Row Analysis in Turbomachines." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-42656.

Full text
Abstract:
A new formulation of the mixing plane boundary condition to analyze the steady state interaction between adjacent rows of a turbomachine, used in conjunction with steady two-dimensional non-reflecting boundary conditions, is presented. Existing mixing plane formulations rely on the differences between some variables at the rows that conform the mixing plane to determine the boundary condition. These differences are driven to zero as the case is converged to the steady state. By contrast, the proposed approach determines the differences that result in the conservation of mass, momentum and energy after the boundary condition is enforced, ensuring conservation at any instant during the iterative process. The reverse flow within the mixing plane boundary is naturally treated, but both inlet and outlet boundary conditions fail when the mixing plane normal velocity tends to zero, giving rise to sharp variations of the fluid variables that must be properly limited to prevent convergence problems. Some examples will be given to demonstrate the ability of the new method to resolve those cases while preserving the boundary condition robustness.
APA, Harvard, Vancouver, ISO, and other styles
4

Hosseini Kordkheili, S. A., and H. Bahai. "Non-Linear Finite Element Static Analysis of Flexible Risers With a Touch Down Boundary Condition." In ASME 2007 26th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2007. http://dx.doi.org/10.1115/omae2007-29379.

Full text
Abstract:
In this paper a non-linear finite element formulation is presented for static analyses of the flexible risers in present of a touch down boundary condition. A four-nodded with twenty four degrees of freedoms pipe elbow element is used to derive the governing finite element formulation. A pipe-soil interaction model is used to identify seabed boundary condition. The effects of buoyancy force as well as steady-state current loading are considered to obtain useful finite element formulation for riser structures. The results of some sample solutions are given to illustrate the capability of the formulation.
APA, Harvard, Vancouver, ISO, and other styles
5

Cheng, Hui, and Jiyun Zhao. "Numerical Investigation on Heat Transfer of Supercritical Water in Rod Bundle Under Suddenly Decreased Mass Flux Condition." In 2016 24th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icone24-60315.

Full text
Abstract:
Supercritical water reactor (SCWR) is one of the most promising nuclear reactor system among generation IV reactors thanks to its high thermal efficiency and simplicity. One of the main features of supercritical water is the strong variation of thermal-physical properties in the vicinity of the pseudo-critical temperature, which makes it very hard to predict the thermal-hydraulic behavior near this point. In this paper, CFD is used to investigate heat transfer of supercritical water in a 2×2 rod bundle with SST k-ε turbulence model. Two steady-state and one transient cases are simulated. The results show that there is strong non-uniform temperature distribution around the circumferential direction. Heat transfer deterioration (HTD) is found in the front of the heated section along the axial direction when the bulk temperature is near the pseudo-critical point due to secondary flow. Comparision of transient and steady-state flow shows that when the mass flux is less than 700 kg/m2s, the temperature in transient state is smaller than that in the steady-state, especially when the mass flux is 400 kg/m2s, the temperature difference is more than 10 °C.
APA, Harvard, Vancouver, ISO, and other styles
6

Fomin, Sergei, and Toshiyuki Hashida. "Rimming Flow of Non-Newtonian Fluids." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-61443.

Full text
Abstract:
The present study is related to the rimming flow of non-Newtonian fluid on the inner surface of a horizontal rotating cylinder. Using a scale analysis, the main characteristic scales and non-dimensional parameters, which describe the principal features of the process, are found. Exploiting the fact that one of the parameters is very small, an approximate asymptotic mathematical model of the process is developed and justified. For a wide range of fluids, a general constitutive law can be presented by a single function relating shear stress and shear rate that corresponds to a generalized Newtonian model. For this case, the run-off condition for rimming flow is derived. Provided the run-off condition is satisfied, the existence of a steady-state solution is proved. Within the bounds stipulated by this condition, film thickness admits a continuous solution, which corresponds to subcritical and critical flow regimes. It is proved that for the critical regime solution has a corner on the rising wall of the cylinder. In the supercritical flow regime, a discontinuous solution is possible and a hydraulic jump may occur. It is shown that straightforward leading order steady-state theory can work well to study the shock location and height. For the particular case of a power-law model, the analytical solution of steady-state equation for the fluid film thickness is found in explicit form. More complex theological models, which show linear Newtonian behavior at low shear rates with transition to power-law at moderate shear rates, are also considered. In particular, numerical computations were carried out for Ellis model. For this model, some analytical asymptotic solutions have been also obtained in explicit form and compared with the results of numerical computations. Based on these solutions, the optimal values of parameters, which should be used in the Ellis equation for correct simulation of coating flows, are determined; the criteria that guarantee the steady-state continuous solutions are defined; the size and location of the stationary hydraulic jumps, which form when the flow is in the supercritical state, are obtained for the different flow parameters.
APA, Harvard, Vancouver, ISO, and other styles
7

Deng, Q., R. D. Burke, Q. Zhang, and Ludek Pohorelsky. "A Research on Waste-Gated Turbine Performance Under Unsteady Flow Condition." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-57870.

Full text
Abstract:
Turbochargers are key components of engine air-paths that must be carefully considered during the development process. The combination of fluid, mechanical and thermal phenomenon make the turbocharger a highly dynamic and non-linear modelling challenge. The aim of this study is to quantify the dynamic response of the turbocharger system across a frequency spectrum from 0.003Hz to 500Hz, i.e. for exhaust gas pulsation in steady state, load steps and cold start drive cycles, to validate the assumption of quasi-steady assumptions for particular modelling problems. A waste-gated turbine was modelled using the dual orifice approach, a lumped capacitance heat transfer model and novel, physics-based pneumatic actuator mechanism model. Each sub-model has been validated individually against experimental measurements. The turbine inlet pressure and temperature and the waste-gate actuator pressure were perturbed across the full frequency range both individually and simultaneously in separate numerical investigations. The dynamic responses of turbine housing temperature, turbocharger rotor speed, waste-gate opening, mass flow and gas temperatures/pressures were all investigated. The mass flow parameter exhibits significant dynamic behaviour above 100Hz, illustrating that the quasi-steady assumption is invalid in this frequency range. The waste-gate actuator system showed quasi-steady behaviour below 10Hz, while the mechanical inertia of the turbine attenuated fluctuations in shaft speed for frequencies between 0.1–10Hz. The thermal inertia of the turbocharger housing meant that housing temperature variations were supressed at frequencies above 0.01Hz. The results have been used to illustrate the importance of model parameters for three transient simulation scenarios (cold start, load step and pulsating exhaust flow).
APA, Harvard, Vancouver, ISO, and other styles
8

Lee, Chihun, Jaehyung Ju, and Doo-Man Kim. "The Dynamic Properties of a Non-Pneumatic Tire With Flexible Auxetic Honeycomb Spokes." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-88199.

Full text
Abstract:
Motivated by our previous study on the flexibility and low local stress of auxetic hexagonal honeycombs in uni-axial loading, we explore the dynamic characteristics of a flexible auxetic hexagonal lattice structure when it is used as the flexible spokes of a non-pneumatic tire. In this study, a modal analysis and the steady state vibration characteristics of NPTs with cellular spokes are investigated with a series of vertical loads and rolling speeds using a commercial finite element code, ABAQUS/Explicit. The angular velocity and the displacement at the hub center and the reaction force on the ground were investigated in the time and frequency domains for the steady state rolling condition for vehicle speeds of 60km/h and 80km/h. The orthotropic properties of the honeycomb spokes create different modal behaviors compared with those of pneumatic tires; e.g., the in-plane shear at the initial mode. The discrete spoke geometry induces a non-homogeneous mass (non-uniformity) distribution, which also causes local vibration effects.
APA, Harvard, Vancouver, ISO, and other styles
9

Zhang, Meng, Wu Zhang, Zhengwei Wu, Weihua Cai, Zhiying Zheng, Yicheng Chen, and Chaofeng Lan. "Instabilities of Pre-Stretched Viscoelastic Flow in Microfluidic Cross-Slot Devices." In ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/mnhmt2019-4120.

Full text
Abstract:
Abstract In this paper we experimentally studied the instabilities of pre-stretched viscoelastic fluid in cross-slot devices. We first investigate the instability of the flow in a standard cross-slot at different Weissenberg numbers without pre-stretch. It is found the viscoelastic flow is transformed from the steady symmetric state to the instabilities states including the steady asymmetric state and the non-periodically oscillated asymmetric state. This is due to the extension of the polymer in the viscoelastic fluid at the stagnation point stretched by the extensional flow in the cross-slot. We then modified the cross-slot channel in which the viscoelastic fluid is pre-stretched before entering the crossroad region. Due to the pre-stretch, elastic energy is pre-stored in the polymer, and the energy required to fully extend the polymer is also different with those extending from equilibrium state. As a result, the flow remains in the steady asymmetric state in all tested Weissenberg number condition.
APA, Harvard, Vancouver, ISO, and other styles
10

Petrie-Repar, Paul, Vasily Makhnov, Nikolay Shabrov, Evgueni Smirnov, Sergey Galaev, and Kirill Eliseev. "Advanced Flutter Analysis of a Long Shrouded Steam Turbine Blade." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-26874.

Full text
Abstract:
An advanced flutter analysis of a final stage turbine row with a new 1.2 meter long shrouded blade is presented. The three-dimensional (3D) unsteady Reynolds Averaged Navier-Stokes (URANS) equations with the Spalart and Allmaras turbulence model were employed to model the flow. The flow entering the last stage is a mixture of saturated vapor and liquid. An equilibrium wet-steam equation of state was used to model the properties of the mixture. Multi-row steady state simulations of the upstream stator row, the turbine row and the extended exhaust section were performed. It was considered important to include the exhaust section in the steady-state simulations in order to accurately predict the pressure profile at the exit of the turbine. The flow simulations were relatively high resolution and the single passage turbine mesh had 798 208 cells. Linearized flow simulations for the turbine row were performed to determine the unsteady aerodynamic work on the blades for the possible aeroelastic modes. An exact 3D non-reflecting boundary condition (3D-NRBC) was applied at the inlet and outlet for the linearized flow simulations to eliminate non-physical reflections at these boundaries. The calculated logarithmic decrement values for the new turbine blade are compared with a reference case for a similar steam turbine blade at a condition known to have a long and safe working history. The new last stage was found to be more stable than the reference case at the flow condition examined.
APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "Non-steady state condition"

1

Miller, Gary D., Fabrizio Beccarisi, E. J. Teichert, Matthew W. Higer, and Peter A. Wenell. An Investigation of Open Loop Flight Control Equations of Motion Used to Predict Flight Control Surface Deflections at Non-Steady State Trim Conditions (Project HAVE TRIM). Fort Belvoir, VA: Defense Technical Information Center, December 2003. http://dx.doi.org/10.21236/ada424491.

Full text
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the extended bibliographies on the topic 'Non-steady state condition' for particular source types:
Journal articles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography