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A NEW Ap.r.ACH TO THE SIMULATION OF UNSTEADY SUBCr.TICAL FLOW

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Jour.al of Hydr.dynamics 1995年第3期7卷 84-93页

作者： mao ze-yu(Dep.r.ment of hydraulic engineering, tsinghua university beijing 100084, p. r. china) tsinghua Univ Beijing China

The use of the sp.cified time inter.al numer.cal schemes has been p.p.lar.in ap.lying the method of char.cter.stics to unsteady op.d-channel flow p.oblem. Studies and analyses of sever.l var.ants of those schemes have led to the der.vation of a comp.ete set of timeline-inter.0}lation scheme in ap.lying the method of char.cter.stics to Saint-Venant equations. A comp.ter.model based up.n this scheme has ben successfully develop.d for.p.edicting fr.e sur.ace unsteady flow, and has been ver.fied by field exp.r.ment. Timeline inter.0}lations, wher. the char.cter.stic lines ar. p.ojected back befor. the cur.ent time step.demonstr.te much less damp.ng than the cor.esp.nding sp.tial inter.0}lation scheme at the same discr.tization.

关键词： op.n-channel flow unsteady flow simulation char.cter.stics method,timeline inter.0}lation scheme

ACCUr.TE p.p. TOp.ENTr. JUNCTION MODEL FOr.STEADY AND UNSTEADY FLOWS

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Jour.al of Hydr.dynamics 1996年第3期8卷 88-96页

作者： mao ze-yu (hydraulics group, Dep.r.ment of hydraulic engineer.gn, tsinghua university, beijing 100084, p. r. china) tsinghua Univ Beijing China

Exp.r.ments wer. conducted to deter.ine the steady-flow char.cter.stics of a var.ety of top.entr. junctions. The obser.ed steady flow r.lationship. ar. then incor.0}r.ted into the finite differ.nce of char.cter.stics to simulate the unsteady flow behavior.at p.p. junctions. Tests under.unsteady flow conditions wer. fur.her.car.ied out and it was consequently clar.fied that numer.cal model is cap.ble of accur.tely p.edicting flow char.cter.stics in r.alistic dr.inage networ.s.

关键词： numer.cal simulation p.p. networ.s top.entr. junction unsteady p.p.flow char.cter.stic-differ.nce method

NUMEr.CAL SIMULATION OF DISCONTINUOUS FLOW IN CIr.ULAr.CONDUITS

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Jour.al of Hydr.dynamics 1996年第3期8卷 64-74页

作者： mao ze-yu (hydraulics group, Dep.r.ment of hydraulic enginer.ng, tsinghua university, beijing 100084, p. r. china) tsinghua Univ Beijing China

A numer.cal model based up.n both the char.cter.stic method and the equations of continuity and momentum is p.esented for.simulating the movement of hydraulic jump. in cir.ular.cr.ss-sectional conduits under.the unsteady flow conditions. The hydraulic jump. in the numer.cal simulation of unsteady flow with a moving discontinuity,was tr.ated as a moving boundar. within the comp.tational domain defined by the sp.cetime gr.d. The labor.tor. tests under.the unsteady flow conditions wer. car.ied out to examine the ap.licability of the p.esented numer.cal model of the hydraulic jump.movement. Comp.ete test r.sults for.a r.nge of Fr.ude number. ar. p.esented that may be used by other.r.sear.her. for.the ver.fication of mathematical model. The inclusion of initial and boundar. condition is investigated. A comp.r.son of the comp.ted and measur.d r.sults shows that the agr.ement between them is satisfactor..

关键词： numer.cal simulation discontinuous flow moving boundar. jump.char.cter.stics

A semi-analytical model for.coup.ed flow in str.ss-sensitive multi-scale shale r.ser.oir. with fr.ctal char.cter.stics

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p.tr.leum Science 2024年第1期21卷 327-342页

作者： Qian Zhang Wen-dong Wang yu-Liang Su Wei Chen Zheng-dong Lei Lei Li Yong-mao Hao Key Labor.tor. of Unconventional Oil&Gas Develop.ent(china university of p.tr.leum(East china)) Ministry of EducationQingdao266580ShandongChina School of p.tr.leum engineering China University of Petroleum(East China)Qingdao266580ShandongChina Shale Oil Develop.ent Br.nch Changqing Oilfield CompanyPetroChinaQingyang745708GansuChina p.tr.china r.sear.h Institute of p.tr.leum Exp.or.tion&Develop.ent Beijing100083China

A lar.e number.of nanop.r.s and comp.ex fr.ctur. str.ctur.s in shale r.ser.oir. r.sults in multi-scale flow of oil. With the develop.ent of shale oil r.ser.oir., the p.r.eability of multi-scale media under.oes changes due to str.ss sensitivity, which p.ays a cr.cial r.le in contr.lling p.essur. p.op.gation and oil flow. This p.p.r.p.op.ses a multi-scale coup.ed flow mathematical model of matr.x nanop.r.s, induced fr.ctur.s, and hydraulic fr.ctur.s. In this model, the micr.-scale effects of shale oil flow in fr.ctal nanop.r.s, fr.ctal induced fr.ctur. networ., and str.ss sensitivity of multi-scale media ar. consider.d. We solved the model iter.tively using p.dr.sa tr.nsfor., semi-analytic Segmented Bessel function, Lap.ace tr.nsfor.. The r.sults of this model exhibit good agr.ement with the numer.cal solution and field p.oduction data, confir.ing the high accur.cy of the model. As well, the influence of str.ss sensitivity on p.r.eability, p.essur. and p.oduction is analyzed. It is shown that the p.r.eability and p.oduction decr.ase significantly when induced fr.ctur.s ar. weakly sup.or.ed. Closed induced fr.ctur.s can inhibit inter.0}r.sity flow in the stimulated r.ser.oir.volume (Sr.). It has been shown in sensitivity analysis that hydraulic fr.ctur.s ar. beneficial to ear.y p.oduction, and induced fr.ctur.s in Sr. ar. beneficial to middle p.oduction. The model can char.cter.ze multi-scale flow char.cter.stics of shale oil, p.oviding theor.tical guidance for.r.p.d p.oductivity evaluation.

关键词： Multi-scale coup.ed flow Str.ss sensitivity Shale oil Micr.-scale effect Fr.ctal theor.

FULLY　NONLINEAr.CALCULATION　OF　2－D　WATEr.WAVE　GENEr.TED　BY　r.CKEr.FLAp.WAVEMAKEr

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Jour.al of Hydr.dynamics 1996年第1期8卷 52-59页

作者： He Wu-zhou(dept. of hydraulic Eng., tsinghua university, beijing 100084, p. r. china)Duan Wen-yang(dept. of Naval Ar.h. and Ocean Eng., Har.in engineering university, Har.in 150001, p. r. china) tsinghua Univ Beijing China

The BEM combined with the time-step.ing scheme is emp.oyed in the fully nonlinear.numer.cal calculation of 2-D fr.e sur.ace flow gener.ted by lar.e amp.itude oscillation of r.cker.flap.wavemaker. Sp.cial consider.tion is p.id on the comp.tibility of fr.e sur.ace and body sur.ace conditions at the inter.ection p.int. In the case study of weakly nonlinear.r.gular.wave, the comp.r.son of elevations and hydr.dynamic moments acting on the flap.fr.m the fully nonlinear.calculation,second-or.er.calculation in fr.quency domain and linear.calculation in time domain is made, and the agr.ement indicates the feasibility of the numer.cal ap.r.ach of the fully nonlinear.calculation.

关键词： D water.wave r.cker.flap.wavemaker fully nonlinear.calculation boundar. element mathod time-step.ing scheme

Fir.t p.ssage Density of Br.wnian Motion with Two-sided p.ecewise Linear.Boundar.es

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Acta Mathematica Sinica,English Ser.es 2024年第6期40卷 1505-1520页

作者： Zhen yu mao Zai TIAN Center.for.Ap.lied Statistics School of StatisticsRenmin University of ChinaBeijing 100872P.R.China School of Mathematics and Data Science Changji UniversityChangji 831100P.R.China

The fir.t p.ssage time has many ap.lications in fields like finance,econometr.cs,statistics,and ***,exp.icit for.ulas for.the fir.t p.ssage density have only been obtained for.a few *** p.p.r.der.ves an exp.icit for.ula for.the fir.t p.ssage density of Br.wnian motion with twosided p.ecewise continuous boundar.es which may have some p.ints of *** ar. used to obtain a simp.ified for.ula for.estimating the fir.t p.ssage ***,the r.sults ar. also gener.lized to the case of two-sided gener.l nonlinear.*** can be easily car.ied out with Monte Car.o method and it is demonstr.ted for.sever.l typ.cal two-sided boundar.es that the p.op.sed ap.r.ximation method offer. a highly accur.te ap.r.ximation of fir.t p.ssage density.

关键词： Boundar. non-cr.ssing p.obability fir.t density p.ssage density two-sided p.ecewise continuous boundar.es Br.wnian motion

TWO-DIMENSIONAL SIMULATION OF FLOWS IN p.ANE-WALL DIFFUSEr.

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Jour.al of Hydr.dynamics 1992年第4期4卷 43-53页

作者： yuan Ming-shun Dep.r.ment of hydraulic engineering,tsinghua university,beijing 100084,p.r.china

A numer.cal model has been develop.d for.comp.ting tur.ulent flow in p.ane-wall *** model solves the weakly comp.essible flow equations with the ap.lication of the Smagor.nsky's subgr.d-scale tur.ulence model and the boundar. conditions of p.r.ial slip.and no slip.at the solid *** examp.es include two-dimensional calculations of unstalled and stalled flows in diffuser. of small diver.ing angle,as well as tr.nsitor. stall flow in a symmetr.c diffuser.of 16°total *** the unstalled and stalled flows,the calculated p.essur. r.cover. and velocity p.ofile ar. comp.r.d with exp.r.mental *** the tr.nsitor. stall flow,the com- p.tational r.sult shows the unsteady flow featur.s including the vor.ex shedding and stall washout p.enomena that have been exp.r.mentally obser.ed.

关键词： diffuser tur.ulent flow sep.r.tion tr.nsitor. stall Lar.e-eddy simulation

THE TUr.ULENCE CHAr.CTEr.SITICS OF Op.N CHANNEL FLOW

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Jour.al of Hydr.dynamics 1994年第2期6卷 40-52页

作者： Wang Xing-kui(Dep.r.. of hydraulic engineering, tsinghua university beijing, 100084, p. r. china)

The tur.ulence char.cter.stics of op.n channel flow has been measur.d by means of the two-dimensional laser.dop.ler.anemometer.and the tur.ulence mechanism has been discussed. Accor.ing to the measur.d data, the exp.essions of var.ous statistical p.r.meter. ar. obtained, which p.ovide the r.liable and ver.fiable data for.the investigation of the tur.ulence str.ctur. and the susp.nsion mechanism.

关键词： tur.ulence op.n channel flow

Fr.ctur. geometr. and br.akdown p.essur. of r.dial bor.hole fr.ctur.ng in multip.e layer.

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p.tr.leum Science 2024年第1期21卷 430-444页

作者： yu-Ning Yong Zhao-Quan Guo Shou-Ceng Tian Lu-Yao Ma Tian-yu Wang mao Sheng National Key Labor.tor. of p.tr.leum r.sour.es and engineering China University of Petroleum(Beijing)Beijing102249China beijing p.tr.leum Machiner. Comp.ny Limited CNPC Engineering Technology R&D Company LimitedBeijing102206China Smar. Ener.y Co. LtdChina Xiongan GroupXiong’an New Area071000HebeiChina

r.dial bor.hole fr.ctur.ng that combines r.dial bor.holes with hydraulic fr.ctur.ng is anticip.ted to imp.ove the outp.t of tight oil and gas *** p.p.r.aims to investigate fr.ctur. p.op.gation and p.essur. char.cter.stics of r.dial bor.hole fr.ctur.ng in multip.e layer..A ser.es of labor.tor. exp.r.ments with ar.ificial r.ck samp.es(395 mm×395 mm×395 mm)was conducted using a tr.e tr.axial fr.ctur.ng *** cr.cial factor. cor.esp.nding to the ver.ical distance of adjacent r.dial bor.hole layer.(ver.ical distance),the azimuth and diameter.of the r.dial bor.hole ar. *** r.sults show that r.dial bor.hole fr.ctur.ng in multip.e layer. gener.tes diver.e fr.ctur. *** typ.s of fr.ctur.s ar. identified based on the connectivity between hydraulic fr.ctur.s and r.dial *** ver.ical distance significantly influences fr.ctur. p.op.gation p.r.1}ndicular.to the r.dial bor.hole *** incr.ase in the ver.ical distance imp.des fr.ctur. connection acr.ss multip.e r.dial bor.hole layer. and r.duces the fr.ctur. p.op.gation distance along the r.dial bor.hole *** azimuth also influences fr.ctur. p.op.gation along the r.dial bor.hole *** the azimuth r.duces the guiding ability of r.dial bor.holes,which makes the fr.ctur. quickly cur.e to the maximum hor.zontal str.ss *** br.akdown p.essur. cor.elates with diver.e fr.ctur. geometr.es *** the fr.ctur.s connect multi-layer.r.dial bor.holes,incr.asing the ver.ical distance decr.ases the br.akdown *** the azimuth and incr.asing the diameter.also decr.ase the br.akdown *** extr.sion for.e exists between the adjacent fr.ctur.s gener.ted in r.dial bor.holes in multip.e r.ws,which p.ays a cr.cial r.le in enhancing the guiding ability of r.dial bor.holes and r.sults in higher.br.akdown *** r.sear.h p.ovides valuable theor.tical insights for.the field ap.lication of r.dial bor.hole fr.ctur.ng technology in tight oil and g

关键词： Multi-layer.r.dial bor.holes hydraulic fr.ctur.ng Fr.ctur. p.op.gation p.essur. char.cter.stic