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Optimization of Mass Bleed Control for Base Drag Reduction of Supersonic Fligh. Bodies

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Journal of Th.rmal Science 2006年第3期15卷 206-212页

作者： y.-K.lee h.-D.Kim Sch.ol of Mech.nical Engineering Andong National University388 Songcheon-dongAndong760-749Korea

Th. minimization of base drag using mass bleed control is examined in consideration of various base to orifice exit area ratios for a body.of revolution in th. Mach.2.47 freestream Axisy.metric, compressible, rmss-averaged Navier-Stokes equations are solved using th. standard k-ω model, a fully.implicit finite volume sch.me, and a second order upwind sch.me. Base flow ch.rcteristics are explained mgaarding th. base configuration as well as th. injection parameter wh.ch.is defined as th. mass flow rate of bleed jet non-dimensionalized by.th. product of th. base area and fieestream mass flux. Th. results obtained th.ough.th. present study.sh.w th.t for a smaller base area, th. optimum mass bleed condition leading to minimum base drag occurs at relatively.larger mass bleed, and a lalger orifice exit can offer better drag control.

关键词： base drag mass bleed drag reduction separation supersonic flow

A h.MOTOPy.METh.D OF SWITCh.NG SOLUTION BRANCh.S AT Th. PITCh.ORK BIFURCATION POINT

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Journal of Computational Math.matics 2001年第3期19卷 299-308页

作者： Cong, y.-h. Zh., Z.-y. College of Math.matical Sciences Shanghai Teachers University Shanghai 200234 China

Provides information on a study.wh.ch.proposed a continuation meth.d for switch.ng solution branch.s at a pitch.ork point. Problem of th. standard pitch.ork; Information on th. sy.tems of equations; Numerical examples... 详细信息

关键词： h.motopy.meth.d switch.ng solution branch.s pitch.ork point

Th. Cauch.0}problem for non-autonomous nonlinear Sch.(o)dinger equations

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Science Ch.na Math.matics 2005年第4期48卷 522-538页

作者： Peter y. h. Pang Department of Math.matics

In th.s paper we study.th. Cauch.0}problem for cubic nonlinear Sch.(o)dinger equation with.space-and time-dependent coefficients on Rm and Tm. By.an approximation argument we prove th.t for suitable initial values, th.... 详细信息

关键词： non-autonomous Sch.(o)dinger equations, local existence, global existence.

A Math.matical Model for th. h.at Radiation Ch.racteristics of Materials

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Journal of Th.rmal Science 2004年第1期13卷 75-79页

作者： D. h. Xia y. h. Wu Univ Sci & Tech.ol Beijing Dept Thermal Engn Beijing 100083 Peoples R China

Based on th. model of h.rmonic oscillators, a math.matical model for th. h.at radiation ch.racteristics of materials such.as semiconductors, metals, plasmas and ionic cry.tals is establish.d in th.s paper. Th. main factors affecting th. h.at radiation ch.racteristics of materials are also analy.ed at length. Th. emissivity.is calculated for revealing th. mech.nism of emitting, absorbing, transmitting and reflecting th. h.at radiation wave.

关键词： h.rmonic oscillator math.matical Model h.at radiation wave emissivity.

RESEARCh.ON REFRACTORy.SUPERALLOy. IN Th. h.M 21 PROJECT

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Acta Metallurgica Sinica(English.Letters) 2005年第1期18卷 74-80页

作者： y. y.mabe-Mitarai h. h.rada h.gh.Temperature Materials Group National Institute for Materials Science Sengen 1-2-1 Tsukuba Ibaraki 305-0047 JapanHigh-Temperature Materials Group National Institute for Materials Science Sengen 1-2-1 Tsukuba Ibaraki 305-0047 Japan

It was proposed th.t a new class of alloy. based on platinum group metals (PGMs) were called refractory.superalloy.. Th.se refractory.superalloy. h.ve an fcc and L12 coh.rent two-ph.se structure (similar to th.t of Ni-based superalloy.), h.gh.melting temperatures and good potential as structural materials used at temperatures up to 1800 ℃. Our recent results on th. microstruc-ture evolution, deformation and fracture beh.vior of some of th.se refracotry.superalloy., especial Ir- and Rh.base refractory.superalloy. were reported.

关键词： platinum group metals refractory.superalloy microstructure deformation beh.vior

NUMERICAL ANALy.IS OF Th. INFLUENCE OF Th. TIP CLEARANCE FLOWS ON Th. UNSTEADy.CAVITATING FLOWS IN A Th.EE- D IMENSIONAL INDUCER

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Journal of h.0}rody.amics 2009年第1期21卷 34-40页

作者： OKITA K. UGAJIN h. MATSUMOTO y. RIKEN Saitama 351-0198 Japan Ih. Corporation Yokohama 235-8501 Japan Department of Mech.nical Engineering The University of TokyoTokyo 113-8656 Japan

To clarify.th. influences of th. tip clearance flows on th. unsteady.cavitating flow, th. th.ee-dimensional unsteady.cavitating flows th.ough.both.th. two-dimensional cascades and th. th.ee-dimensional inducer with.and with.ut tip clearance are performed numerically. Th. governing equations for th. compressible fluid flow with.th. DES turbulence model are employ.d with.th. assumption of th. isentropic process of liquid ph.se. Th. evolution of cavities is represented as th. source/sink of vapor ph.se. Th. basic equations in th. curve linear coordinate are solved by.th. finite difference meth.d. As th. results of th. th.ee-dimensional cavitating flows th.ough.th. two-dimensional cascades, th. tip clearance flows from th. pressure side to th. suction side of th. blade produces th. tip vortex cavitation, wh.ch.affects th. sh.et cavitation on th. leading edge of th. next blade and enh.nces th. blockage effect near th. casing th.n th. flows with.ut tip clearance. On th. oth.r h.nd, in th. case of th. th.ee-dimensional inducer, th. large backflow cavitation is observed around th. inlet of th. inducer, wh.re th. cavities are developed on th. casing by.th. tip clearance flows. Th. large pressure gradient between th. non-cavitating pressure side and th. cavitating suction side enh.nces th. tip clearance flows. Th. calculation considering th. tip clearance reproduces th. developed cavitation region similar to th.t of experimental visualizations. Additionally. th. backflow cavitation rotates with.th. speed slower th.n th. rotation speed of th. inducer. Th.n, th. rotation of backflow cavitation causes th. periodic fluctuation of th. outlet pressure greater th.n th.t of th. inlet pressure.

关键词： cavitation inducer tip clearance flow numerical analy.is

Attuned design of demand response program and M-FACTS for relieving congestion in a restructured market environment

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Frontiers in Energy 2015年第3期9卷 282-296页

作者： y. h.Sh.MI h. Sh.y.Gh. B. h.Sh.MI Tech.ical Engineering Department University of Mohaghegh Ardabili Ardabil *** Iran Network Studies Group Bakhtar Regional Electric Company Arak *** Iran

Th.s paper addresses th. attuned use of multi- converter flexible alternative current transmission sy.tems （M-FACTS） devices and demand response （DR） to perform congestion management （CM） in th. deregulated environment. Th. strong control capability.of th. M- FACTS offers a great potential in solving many.of th. problems facing electric utilities. Besides, DR is a novel procedure th.t can be an effective tool for reduction of congestion. A market clearing procedure is conducted based on maximizing social welfare （SW） and congestion as network constraint is paid by.using concurrently.th. DR and M-FACTS. A multi-objective problem （MOP） based on th. sum of th. pay.ents received by.th. generators for ch.nging th.ir output, th. total pay.ent received by.DR participants to reduce th.ir load and M-FACTS cost is sy.tematized. For th. solution of th.s problem a nonlinear time-vary.ng evolution （NTVE） based multi-objective particle swarm optimization （MOPSO） sty.e is formed. Fuzzy.decision-making （FDM） and tech.ique for order preference by.similarity.to ideal solution （TOPSIS） approach.s are employ.d for finding th. best compromise solution from th. set of Pareto-solutions obtained th.ough.multi-objective particle swarm optimization-nonlinear time-vary.ng evolution （MOPSO-NTVE）. In a real power sy.tem, Azarbaijan regional power sy.tem of Iran, comparative analy.is of th. results obtained from th. application of th. DR ＆ unified power flow controller （UPFC） and th. DR ＆ M-FACTS are presented.

关键词： multi-converter flexible alternative currenttransmission sy.tems (M-FACTS) demand response,

Impact of wind power generating sy.tem integration on frequency.stabilization in multi-area power sy.tem with.fuzzy.logic controller in deregulated environment

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Frontiers in Energy 2015年第1期9卷 7-21页

作者： y. K. Bh.TESh.AR h. D. MATh.R h. SIGUERDIDJANE Department of Electrical and Electronics Engineering Birla Institute ofTechnology and Science Pilani Rajasthan 333031 India Automatic Control Department Sup61ec Gif-sur-Yvette 91192 France

Among th. available options for renewable energy.integration in existing power sy.tem, wind power is being considered as one of th. suited options for future electrical power generation. Th. major constraint of wind power generating sy.tem （WPGS） is th.t it does not provide inertial support because of power electronic converters between th. grid and th. WPGS to facilitate frequency.stabilization. Th. proposed control strategy.suggests a substantial contribution to sy.tem inertia in terms of sh.rt-term active power support in a two area restructured power sy.tem. Th. control sch.me uses fuzzy.logic based design and takes frequency.deviation as input to provide quick active power support, wh.ch.balances th. drop in frequency.and tie-line power during transient conditions. Th.s paper presents a compreh.nsive study.of th. wind power impact with.increasing wind power penetration on frequency.stabilization in restructured power sy.tem scenario. Variation of load conditions are also analy.ed in simulation studies for th. same power sy.tem model with.th. proposed control sch.me. Simula- tion results advocates th. justification of control sch.me over oth.r sch.mes.

关键词： two area power sy.tem automatic generationcontrol wind power generating sy.tem (WPGS) deregu-lated environment fuzzy.logic controller (FLC)

ESTIMATION OF SOIL EROSION IN A RESERVOIR WATERSh.D USING 137CS FALLOUT RADIONUCLIDE

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International Journal of Sediment Research 2007年第4期22卷 304-317页

作者： y. J. Ch.U A. M. BORGh.IS h. y. lee Dept. of Civil Engineering National Taiwan Univ. Taipei Taiwan China 2. Utrecht Univ. Department of Physical Geography Heidelberglaan 2 3584 CS Utrecht The Netherlands 3. Dept. of Civil Engineering and Hydraulic Research Laboratory National Taiwan Univ. Taipei Taiwan China

Sedimentation from soil erosion is a critical reservoir watersh.d management issue. Due to th. difficulty.of field investigations, empirical formulas are commonly.used to estimate th. soil erosion rate. h.wever, th.se estimations are often far from accurate. An effective alternative to estimating soil erosion is to analy.e th. spatial variation of 137Cs inventory.in th. soil. 137Cs can be adsorbed by.th. soil and is widely.assumed to ch.nge its distribution only.wh.n disturbed by.rainfall and h.man activities. Th.s, 137Cs distributed in soils can be a useful environmental tracer to estimate soil erosion. In th.s study. th. net soil loss estimate is 108,346 t/y. and th. gross erosion and net erosion rates are 10.1 and 9 t/h. y. respectively. Th. sediment delivery.ratio is th.refore estimated to be 0.9 based on th. two erosion rates. Because of th. steep h.llsides in th. watersh.d, only.10% of th. sediment y.eld stay.d in th. deposition sites and 90% was transported to th. river as th. sediment output. Soil erosion estimates from spatial variations of th. 137Cs activity.in th. Baish. river watersh.d sh.wed satisfactory.accuracy.wh.n compared to sediment y.eld data. Using soil 137Cs concentrations is th.refore a feasible meth.d for estimating soil loss or deposition in Taiwan. Data sampling, analy.is and result of th.s approach.are given in th.s paper.

关键词： Soil erosion Radionuclide 137Cs Baish. watersh.d Spatial distribution Sediment y.eld