ON INSTABILITY OF DILUTE FIBER SUSPENSIONS IN AN AXISYMMETRIC TAYLOR-COUETTE FLOW

1. INTRODUCTION The shear-driven flow between independently rotating concentric cylinders is named as Taylor- Couette flow after the standout work of Taylor in 1923 and his later research in this field. Since then,there have been alot of literatures relatedto this problem. Among them,the hydrodynamic in- stability of Taylor-Couette flowin the Newtonian fluid has been one of the most attractive topics . The review written by Tagg[1]has summarized these fruits .Inrecent years ,theinstabi…     

RESEARCH ON THE MOTION CHARACTERISTICS OF FIBER SUSPENSIONS IN A WEDGE-SHAPED FLOW

1.　INTRODUCTIONTheliquidorgasflowofsolidfibersuspensionsconcernssomediffcultproblemsinthetheoreticalresearchofmultiphaseflowandNon-Newtonianflow.Sotheresearchofithasgreattheoreticalvalues.Atthesametime,theapplicationoftheflowwithfibersuspensionsisveryextensive.Inmaterialsscience,compositematerialsarebeingpaidmoreandmoreattentiontoshort-fibermaterialarethemostcommononeinvariouscompositematerials.Themoldingandmachiningofshort-fibermaterialhavemuchtodowiththedynamiccharacteristicsoftheflow…     

RESEARCH ON DISTRIBUTION FUNCTION AND ORIENTATION TENSORS OF FIBER SUSPENSIONS IN WEDGE-SHAPED FLOW FIELD

1. INTRODUCTIONUnderstanding the rheological behavior of nondilute fiber suspensions is currently of great interest both practically and theoretically. Whenever such a flow is formed, the fibers and the fluid act on each other. The existence and motion of…     

TRANSPORT EFFICIENCY OF THE SPIRAL FLOW IN CIRCULAR PIPE

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＧｒａｉｎｍａｔｅｒｉａｌｔｒａｎｓｐｏｒｔｉｎｐｉｐｅｆｌｏｗｈａｓａｈｉｓｔｏｒｙｏｆｍｏｒｅｔｈａｎｏｎｅｈｕｎｄｒｅｄｙｅａｒｓ .Ｉｎｒｅｃｅｎｔｓｅｖｅｒａｌｄｅｃａｄｅｓｔｈｅｔｅｃｈｎｏｌｏｇｙｈａｓｂｅｅｎｄｅｖｅｌｏｐｉｎｇｖｅｒｙｒａｐｉｄ ｌｙ .Ｔｈｅｒｅａｒｅｍｏｒｅｔｈａｎ 2 6ｓｏｒｔｓｏｆｍａｔｅｒｉａｌｓｓｕｃｈａｓｃｏａｌ,ｓａｎｄ ,ｃｏｎｃｅｎｔｒａｔｅ ,ｔａｉｌｉｎｇｓａｎｄｏｔｈｅｒｇｒａｉｎｍａｔｅ ｒｉａｌｓａｒｅｔｒａｎｓｐｏ…     

STEADY ENTRANCE FLOW IN A STRAIGHT CIRCULAR PIPE WITH SLOWLY VARYING CROSS SECTION

1.INTRODUCTIONItiswellknownthatmanyvasculardiseasesarecloselyrelatedtothebloodflowinves-sels[1-3j.Thebloodflowthroughthearterieswithvaryingcrosssectionhasheldthein-terestsofmanyinvestigatorsforalongtimeL4-6j.Inthepreviousstudies,thebloodf1owinarterieswas,however,assumedtobefullydeveloped.Sincestenosesfrequentlydevelopatsitesneartheoriginofbranches[2-3j,whichareintheentranceregion,itisimportanttostudytheentranceflowinaconverging-divergingpipe,whichisamodelofentrancestenosis-Manyinvestigat…     

NUMERICAL SIMULATION OF TURBULENT FLOW CHARACTERISTICS IN A CURVED PIPE WITH A BAFFLE

A numerical study on the characteristics of developing turbulent flow in a curved pipe with a baffle was carried out in body-fitted coordinates with the k-ε model turbulence. A curved duct of square cross-section was examined first, and the results agree very well with the experimental data. Then two kinds of pipes, a normal curved pipe and that with a baffle were studied. The computational results are presented and compared with each other to illustrate the changes of the flow after adding the baffle. The longitudinal velocity in the pipe with a baffle was characterized by outer velocity bigger than the inner one. The secondary flow was characterized by four-vortex structure with the intensity reduced, which results in the equability of the flow field of the cross-section compared with that without a baffle, and has much more significant meaning in engineering.     

THE METHOD OF SEMI-FALSE TRANSIENT FOR COMPUTING THE FLOW INTO POROUS MEDIUM IN THE CIRCULAR PIPE

The method of semi-false transient was used to numerically compute the incompressible steady flow into the porous medium n this paper. The fundamental equations were established and numerically solved in the united flow field,which included the space region and the porous region. The non-equidistant non-orthogonal semi-staggered mesh system was used in the method of semi-false transient.The computational results of two problems concerning the flow into porous medium from space region,in which there was the backward flow besides main flow, were obtained adn discussed. It is seen from the results that the backward flow is generally not present in the porous medium as the osmotic resistance is very large.     

NUMERICAL SIMULATION OF DISCONTINUOUS FLOW IN CIRCULAR CONDUITS

ＮＵＭＥＲＩＣＡＬ　ＳＩＭＵＬＡＴＩＯＮ　ＯＦ　ＤＩＳＣＯＮＴＩＮＵＯＵＳ　ＦＬＯＷ　ＩＮ　ＣＩＲＣＵＬＡＲ　ＣＯＮＤＵＩＴＳＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＯＦＤＩＳＣＯＮＴＩＮＵＯＵＳＦＬＯＷＩＮＣＩＲＣＵＬＡＲＣＯＮＤＵＩＴＳ￥ＭａｏＺｅ...     

THE NUMERICAL COMPUTATION OF TURBULENT FLOW IN TEE-JUNCTION

A numerical model for calculating the turbulent flow in tee-junction is given in thispaper.The calculations are performed using a finite-difference procedure,and turbulence is ac-counted for by using a two-equation k-ε model of turbulence.Results,consisting of mean veloci-ty profiles and pressure losses due to the junction,have been obtained,and show that the flowsituation in tee-junction is very complex.The computed results agree closely with the experimen-tal data and validate that the present model is reasonable and the numerical calculations are suc-cessful.     

AN EXPERIMENTAL AND NUMERICAL INVESTIGATION OF THE STARTING FLOW OF A UNIFORMLY ACCELERATING CIRCULAR CYLIINDER

The starting flow around a uniformly accelerated circular cylinder is investigatedby flow visualization techncque and solving N-S equations numerically in detail.The results ofthe starting flow are similar with those of the impulsively started one.At lower Re_α,numbers the“phenomenon a”is revealed;the“phenomenon β”appears at higher Re_α numbers,but withonly one secondary vortex.At the early stage of the starting vortex formation,the flow islaminar;at the later stage,the flow transforms into turbulent flow.The velocity distribution inthe flow field is measured with the multiwires installment.The calculational results are comparedwith the results of experiment,and both are in agreement with each other.