THE NUMERICAL CALCULATION FOR THE STERN FLOW OF THREE DIMENSIONAL SURFACE SHIP WITH MULTI-PRO-PELLERS IN OPERATION

In this paper the complex structure and pattern of ship stern flow driven by multi-propellers is simulated numerically by using RANS equations with K-ε turbulence model and propeller lifting surface theory as essential research tool and coupling the computer code of ship stern flow to the computer code of propeller performance prediction through the medium of body force.A ship model with four propellers is selected as the numerical example.Detailed computational results are presented graphically and the qualitative and quantitative analysis is made. Finally,the comparison between the calculated result and the available experimental data is made.The agreement between them is satisfactory.     

A SEPARATED－LAYER FINITE ANALYTIC METHOD FOR NUMERICAL SIMULATION OF A THREE－DIMENSIONAL VISCOUS FLOW FIELD AROUND A SHIP STERN

ＡＳＥＰＡＲＡＴＥＤ－ＬＡＹＥＲＦＩＮＩＴＥＡＮＡＬＹＴＩＣＭＥＴＨＯＤＦＯＲＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＯＦＡＴＨＲＥＥ－ＤＩＭＥＮＳＩＯＮＡＬＶＩＳＣＯＵＳＦＬＯＷＦＩＥＬＤＡＲＯＵＮＤＡＳＨＩＰＳＴＥＲＮＬｉＴｉｎｇ－ｑｉｕ；Ｍｉａｏ...     

THE RESEARCH OF NATURAL THREE－DIMENSIONAL NUMERICAL MODEL FOR WATER－SEDIMENT TWO－PHASE FLOW AND SEDIMENT MOVING REGULARITY NEAR THE RIVER BOUNDARY

ＴＨＥ　ＲＥＳＥＡＲＣＨ　ＯＦ　ＮＡＴＵＲＡＬ　ＴＨＲＥＥ－ＤＩＭＥＮＳＩＯＮＡＬ　ＮＵＭＥＲＩＣＡＬ　ＭＯＤＥＬ　ＦＯＲ　ＷＡＴＥＲ－ＳＥＤＩＭＥＮＴ　ＴＷＯ－ＰＨＡＳＥ　ＦＬＯＷ　ＡＮＤ　ＳＥＤＩＭＥＮＴ　ＭＯＶＩＮＧ　ＲＥＧＵＬＡＲＩＴＹ　ＮＥ...     

PERTURBATION SOLUTION OF SECONDARY FLOW OF POWER-LAW FLUID IN HELICAL PIPES WITH CIRCULAR CROSS-SECTION

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｆｌｏｗｉｎｈｅｌｉｃａｌｐｉｐｅｓｉｓｖｅｒｙｃｏｍｐｌｅｘａｎｄｖｅｒｙｉｍｐｏｒｔａｎｔｉｎｂｏｔｈｔｈｅｃｈｅｍｉｃａｌｉｎｄｕｓｔｒｙａｎｄｔｈｅｐｅｔｒｏｌｅｕｍｉｎｄｕｓｔｒｙ .ＡｌｏｔｏｆｗｏｒｋｈａｓｂｅｅｎｄｏｎｅｂｙＭｕｒａｔａｅｔａｌ.[1] ,Ｗａｎｇ[2 ] ,Ｇｅｒｍａｎｏ[3 ,4 ] ,Ｋａｏ[5] ,Ｔｕｔｔｌｅ[6] ,ａｎｄＬｉｕ[7] .ＢｕｔｔｈｅｙｏｎｌｙｓｔｕｄｉｅｄｔｈｅＮｅｗｔｏｎｉａｎｆｌｕｉｄｉｎｈｅｌｉｃａｌｐｉｐｅｓ .Ｔｈｅｒｅｉｓｎｏ…     

AN EXPERIMENTAL STUDY ON THREE DIMENSIONAL STRUCTURE OF BAROCLINIC WAVY JET STREAM IN A ROTATING ANNULUS SUBJECT TO RADIAL TEMPERATURE GRADIENT

1.　INTRODUCTIONThe research on jet,which is a typical flow pattern in atmosphere,has made a greatprogress in both theory and observation.There existsa striking similar feature between thejetstream of baroclinic fluid in a rotating annulussystem and the defined one of IMO( Inter-national Meteorological Organization,Upper Air Technical Commission) .Forsuch a similarfeature,more and more attention hasfocused on the experimental simulation of jetstream ina baroclinic fluid system based on…     

ON NONLINEAR STABILITY IN NONPARALLEL BOUNDARY LAYER FLOW

The nonlinear stability problem in nonparallel boundary layer flow for two-dimensional disturbances was studied by using a newly presented method called Parabolic Stability Equations (PSE). A series of new modes generated by the nonlinear interaction of disturbance waves were tabulately analyzed, and the Mean Flow Distortion (MFD) was numerically given. The computational techniques developed,including the higher-order spectral method and the more effective algebraic mapping, increased greatly the numerical accuracy and the rate of convergence. With the predictor-corrector approach in the marching procedure, the normalization condition was satisfied, and the stability of numerical calculation could be ensured. With different initial amplitudes, the non linear stability of disturbance wave was studied. The results of examples show good agreement with the data given by the DNS using the full Navier-Stokes equations.     

CONTINUOUS WAVELET TRANSFORM OF TURBULENT BOUNDARY LAYER FLOW

The spatio-temporal characteristics of the velocity fluctuations in a fully-developed turbulent boundary layer flow was investigated using hotwire. A low-speed wind tunnel was established. The experimental data was extensively analyzed in terms of continuous wavelet transform coefficients and their auto-correlation. The results yielded a potential wealth of information on inherent characteristics of coherent structures embedded in turbulent boundary layer flow. Spatial and temporal variations of the low- and high- frequency motions were revealed.     

EFFECT OF SOLID PARTICLES ON STABILITY FLOW IN THE BOUNDARY LAYER ON A FLAT PLATE

ＥＦＦＥＣＴＯＦＳＯＬＩＤＰＡＲＴＩＣＬＥＳＯＮＳＴＡＢＩＬＩＴＹＦＬＯＷＩＮＴＨＥＢＯＵＮＤＡＲＹＬＡＹＥＲＯＮＡＦＬＡＴＰＬＡＴＥ￥ＬｉｎＪｉａｎ－ｚｈｏｎｇ；ＺｈｏｕＺｅ－ｘｕａｎＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃｓ，ＳｔａｔｅＫｅｙＬａ...     

CFD SIMULATION OF 3D FLOW IN LARGE-BORE AXIAL-FLOW PUMP WITH HALF-ELBOW SUCTION SUMP

1. INTRODUCTION Axial-flow pumps are usually designed for pumping large volumes of water against low pressure head. Suction sump is one of key elements in pump stations. For pumps with larger than 2 m, closed type suction sump plans are used to provide pr…     

EXPERIMENTAL STUDIES AND NUMERICAL CALCULATION ON TURBULENT BOUNDARY LAYER OF WATER FLOW ALONG CURVED SURFACE

This paper will introduce experimental studies and numerical calculation onturbulent boundary layer of water flow along curved surface in our country in recent years.Onthe basis of the experimental studies,the effects of curvature and roughness on velocitydistribution and pressure distribution and the change of turbulent flow boundary layer onoverflow bucket concave surface is discussed.We proposed the empirical formula of velocity,pressure and the change of turbulent flow boundary layer on outlet bucket concave.According tothe momentum principle,we have deduced the momentum integral equation full water depthboundary layer and using the element as control unit inside the boundary layer on concavesurface of bucket.Combining with continuity equation,we have computed the boundary layerdevelopment on the bucket of a spillway.Compared with the field experimental data,thecalculation results are available.Under polar coordinates,a mathematical model for simulatingtime-averaged flow characteristics in concave surface of bucket is established.The turbulent flowfield on concave surface of bucket is calculated by SIMPLE method and this mathematicalmodel.The flow velocity field,pressure field,distribution of turbulent kinetic energy,distribution of turbulent energy dissipating rate and distribution of shear stress are available.Thecalculation value is consistent with measured test data.     

TURBULENT BOUNDARY LAYER DEVELOPMENT IN THE ENTRANCE REGION OF A SMOOTH ROUND PIPE

The study of the turbulent boundary layer along a smooth round pipe is of greatsignificance both in practice and in theory.In this paper,the formulae for calculating the tur-bulent boundary layer thickness are obtained by solving the momentum integral equation of theboundary layer in which the assumptions of the logarithmic law and exponential law of velocitydistribution are adopted.The methods for calculating the mean flow velocity in the developingregion of turbulent boundary layer in a round pipe are proposed.The relation between the expo-nent n and the factor μ·δ/ν is studied and a formula for calculating the exponent n is obtained.     

COMPRESSIBILITY BOUNDARY LAYER THEORY AND ITS SIGNIFICANCE IN COMPUTATIONAL HYDRODYNAMICS

ＣＯＭＰＲＥＳＳＩＢＩＬＩＴＹＢＯＵＮＤＡＲＹＬＡＹＥＲＴＨＥＯＲＹＡＮＤＩＴＳＳＩＧＮＩＦＩＣＡＮＣＥＩＮＣＯＭＰＵＴＡＴＩＯＮＡＬＨＹＤＲＯＤＹＮＡＭＩＣＳ￥ＣｈａｒｌｅｓＣ．Ｓ．Ｓｏｎｇ（ＵｎｉｖｅｒｓｉｔｙｏｆＭｉｎｎｅｓｏｔａ，Ｍｉｎｎｅａ...     

HOT WIRE MEASUREMENT OF TURBULENT BOUNDARY LAYER ON A FILM COOLING PLATE WITH DIFFUSION HOLES

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｆｉｌｍｃｏｏｌｉｎｇｏｆｇａｓｔｕｒｂｉｎｅｓｂｌａｄｅｓａｎｄｃｏｍ ｂｕｓｔｏｒｓｉｓａｔｙｐｉｃａｌｈｅａｔ/ｍａｓｓｔｒａｎｓｆｅｒｐｒｏｂｌｅｍｗｈｉｃｈｈａｓｂｅｅｎｍａｓｓｉｖｅｌｙｓｔｕｄｉｅｄｆｒｏｍ 195 0’ｓ .Ｆｏｒｉｎｃｒｅａｓｉｎｇｔｈｅｅｆｆｉｃｉｅｎｃｙｏｆｇａｓｔｕｒｂｉｎｅｓｔｈｅｉｎｌｅｔｇａｓｔｅｍｐｅｒａｔｕｒｅｈａｓｂｅｅｎｒａｉｓｅｄ .Ｔｈｅｒｅｆｏｒｅ ,ｔｏｐｒｅｖｅｎｔｃｏｒｒｏｓｉｏｎａｎｄｅｒｏｓｉｏｎａｔｔｈ…     

MEASUREMENT OF HYDRODYNAMIC FORCES ACTING ON A CIRCULAR CYLINDER NEAR A PLANE BOUNDARY IN STEADY FLOW

In this paper,the characteristics of hydrodyna(?) forces on a circular cylindernear a plane boundary have been studied experimentally in w(?) tunnels.The drag coefficientC_D,mean lift coefficient C_(L0),T.m.s.lift coefficient C_(L Tms),maximum lift coefficient C_(L max) andfluctuating lift coefficients C'_(L Tms),C'_(L max),and lift(vortex shedding)frequency have been mea-sured on condition that the thickness of plane boundary layer,δ,was 0.1D(D is the diameter ofthe cylinder)at the station of the centre of the cylinder,and Reynolds number,Re,varied from4.5×10~3 to 1.76×10~5.The regularity of the change of these coefficients with Re and gap ratioG/D is found.The measurement of the lift frequency shows that a strong non-linear coupling ac-tion appears when the gap ratio between the circular cylinder and plane,G/D,reaches 0.5,andthe shedding of regular vortex is suppressed when G/D=0.2.