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This paper deals with a longitudinal mixing of particles which are instantaneously releasedin a bounded turbulent shear flow. The movements of particles are described in view of theLagrangian particle analysis. The similarity of concerned phenomena to the turbulent diffu-sion by continuous movements in a uniform turbulent flow is studied. The discrepancy oftwo phenomena is also shown with some discussions. In the mixing the Lagrangian auto-correlation function plays the most important role. Some auto-correlation functions in aturbulent shear flow are introduced and their dependency on a released position and traveltime is discussed. The discussion gives useful information of estimating the Lagrangianauto-correlation function in a turbulent shear flow. Finally, the model of the Lagrangianauto-correlation function proposed by the authors in the other paper is referred, and thegeneral features of longitudinal mixing given by the proposed model are compared withthe past knowledge experimentally obtained.

This paper deals with effects of shape of a dropshaft intake to energy dissipation and air transport control. First, free-surface swirling flows in vertical dropshafts are modeled and their solutions are derived. With these solutions, the energy dissipation effects of the dropshafts are examined by the vertical change of vertical momentum flux and kinematic energy, and some results of practical use are obtained. Next, the relations between the dropshaft shape and air entrainment are examined through dimensional analysis. Three types, that is, standard vortex flow dropshaft, helicoidal-ramp dropshaft and vortex flow dropshaft with contraction are analyzed. A hydraulic parameter influencing air entrainment is found and the excellence of the helicoidal-ramp dropshaft is clarified.

It is well known that the secondary flow can be observed in a straight open channel, however, it is elusive to be detected because of its small magnitude and unstableness. The secondary flow is investigated experimentally or numerically by many researchers. In this paper vortex motions induced by the secondary flow are classified on the basis of its cause; velocity gap, flow boundary and bed-generated turbulence, and discussed by using the results of 3-D LDA measurements, flow visualization in a transverse cross section and an algebraic stress model (Naot-Rodi model). It is found that there are some difference between the time-mean secondary flow obtained by LDA and N-R model and the instanteneous secondary flow by the flow visualization.

Some hydrodynamic aspects of tidal inlet defined as the relatively short channel connecting bay and ocean is treated. Often such system exhibits irregular geometry and complicated flow patterns at the ocean- and bay-side. As a result of the large variations in depth and width, the velocity field contains both vertical and horizontal eddies. These eddies often are dominant features rather than perturbations on the main flow.In the context of this paper, an idealized and simple model basin is treated. It is because that this research is aimed to improve the fundamental understanding for the inlet-related problems.Only tidal forcing is considered. Emphasis is on the bay response of water level to outer sea, tidal exchange process through the inlet and local sea-bed variations near the inlet.

In the present paper, we assume the swirling motion of tatsumaki as the Rankine vortex moving with a constant velocity and analyze the unsteady horizontal flow at any point in the tatsumaki path.The inertial force on bodies due to the action of unstady/ accelerating flow is obtained by using the velocity potential for inviscid flow. The inertial force and the drag which is dependent on the square of the fluid velocity may be combined with the Morison's equation, which constitutes the total fluid force.The results are discussed and examined, comparing to the steady-state wind loadings with a constant velocity.

In the previous paper^1)- the authors presented a bed-load equation which was derived from their constitutive relations of debris flow. The equation underestimates somewhat the bed-load rate in the range of non-dimensional shear stress smaller than 0.2.This paper discusses a refinement of the constitutive equations in smaller range of shear stress, but greater than the critical value of initiation of sediment movement.A bed-load equation, then, is derived from the refined constitutive relations.The formula is tested in terms of the data obtained from flume tests carried by using both of sand particles and glass beads.

This paper deals with the mixing phenomena in a main flow direction within a bounded turbulentshear flow in view of Lagrangian aspect.Data obtained by numerical simulations are analized through application of Taylor's classicturbulent diffusion theory by continuous movements: Main objectives are to disclose the relations ofLagrangian properties, such as Lagrangian auto-correlation coefficient, integral time scale and dis-persion coefficient with Eulerian Flow properties and also to obtain differences of these Lagrangianproperties between two and three dimensional turbulent shear flows.As results of this study, it is concluded that the auto-correlation coefficient in a three dimensionalturbulent shear flow is quite different from that in a two dimensional one, and that the lateral non-uniformity of velocities averaged in a vertical direction and the lateral turbulent intensity are mosteffective on the longitudinal mixing in three dimensional turbulent shear flows.

This paper deals with the numerical analysis of the two-dimensional buoyant surfacejets. The fundamental equations used here are the k-e model in which Launder's studyconcerning the turbulent structure of the stratified flows is involved.The brief description about the mathematical form of e-equation is given using thehomogeneous shear flow turbulence formulated by Hinze. Then it is pointed out from thenumerical results including the vertical distributions of hydraulic variables that the effectsof buoyancy term in the e-equation is quite sensitive for the stratification of water tem-perature observed in the previous experimental studies.

Before and behind bed protection works in natural rivers, bed roughnessabruptly changes from smooth to rough and/or rough to smooth. This paper dealswith water surface profiles and turbulent structures of open channel flows producedby sudden changes in bottom roughness experimentally and theoretically.Changes in vertical distribution of sediment concentration under the fullysuspended condition are also discussed. The transition of flow depth was found tobe mainly depend on the bed slope and classified into three types of flow patterns.In the downstream reach after roughness change, distributions of the velocity andturbulence property vary with development of the internal boundary layer, in whichthe transfer of turbulence energy by convection and vertical diffusion play dominantrole in the turbulence energy budget. The calculated results of the k-e andsediment transport models agree well with the experimental ones.

In a curved channel there are spiral motions occurred by centrifugal force. And in an openchannel that consists of a main channel and flood plains, the flow has a complex turbulent structurebecause of interaction between flow in a main channel and it in flood plains. So it is difficult to clarifycharacteristics of an open channel flow in bend with flood plains.In this paper it is the objective to elucidate the turbulent structure of this flow by measurementsof velocity and flow visualization. From experimental results it is comfirmed that three independentspiral motions exist in bend with two flood plains.

This paper describes an experimental investigation of the profiles of mean velocitiesand some turbulence properties in a two-dimensional free surface shear flow. The exper-iments were performed under the condition of greater aspect ratio than 10, to obtain thetwo-dimensional flow in a rectangular open channel.The experimental results show that the mean velocity profiles are well described bythe logarithmic distribution, and that the Karman constant k and the integral constantAs, Ar may be treated as constants which are independent of the Reynolds number, theFroude number and the relative roughness height. However, the values of theses con-stants in a free surface shear flow are somewhat different from these in a pipe flow, andthe following values may be recommended, that is, k=0.33, As=2.2 and Ar=8.3.According to the Reynolds number similarity, the turbulence properties are normalizedwith the flow depth, the friction velocity and the local mean velocity. And the verticaldistribution of the normalized turbulence properties, such as, the turbulence intensity, theEulerian mean scale, the energy dissipation rate, the Taylor's dissipation scale, the Kol-mogorov's lacal scale, the Lagrangian mean scale and the turbulent diffusion coefficientare described by the universal function of the relative depth, respectively.

Open-channel turbulent flows often present three dimensional aspects because of the exis-tence of the longitudinal eddies. The longitudinal eddies can be separated into those of the firstkind (originated from the shape of the cross-section) and those of the second kind (rerated to thebursting phenomenon in the boundary layer).In this paper the characteristics of the longitudinal eddies in the small width-to-depth ratiochannel are investigated using experimental results of the boundary shear stress distribution, sand-ridges visualized by Cameron effect and velocity vectors measured by laser doppler anemome-ter. Experimental results show that the shape of the cross-section has an effect on the arrange-ment, stability and scale of the longitudinal eddies.

The characteristics of flow vary with space over sand waves. It is important to consider thisnouniformity in the modeling of motions of suspended particles, but few methods for calculationof suspended load have been proposed by consideration of this efects. In this paper mean velocityand turbulent strength of flow are discussed experimentally over a two-dimensinal sand wave andthe motion of suspended particle are formulated using these results and authors' theory on modelof particle motion over plane bed. The probability density function of heigth and step length ofsuspended particle are calculated, and theoretical results are found to fit experimental results well.Then the distribution of pick-up rate along a sand wave is calculated based on this theory.

This paper deals with the characteristics of open channel flows around a circular cylinder, which are investigated on the basis of experimental results. The measurments of velocity weremade by a hot-film flowmeter, and the measurements of the bottom shear stress by a flush-mounting-probe. From these experimental data, some qualitative properties of the structure of turbulence ina wake are revealed, that is, the distribution of mean velocity, Reynolds stress and the eddy viscositynear the bed can be approximated by the result of two dimensional wake.

The graph theory is used to express the complex structure of pipe and channel networks inthis paper. First, a generalized new method and its applicability to analize steady flows in pipenetworks are discussed. This new method is also applied to steady flows in open-channel net-works. As for unsteady flows in open-channel networks, another new method is proposed. Thesenew methods for open-channel networks are applied to numerical simulations of a river networkin Osaka City and computed values are compared with observed ones.

This paper deals with the vibration characteristics of hydraulic structures, using poli-carbonate plastic cylinders placed in open channel flows for the first step of the wholeresearch programs. The basic vibration characteristics of an isolated test cylinder by fluidforces, and the interaction effects of neighbouring cylinders to the vibration of the testcylinders are investigated.The experimental results are as follows. 1) As the vibration phenomena are veryimportant in this experimental conditions, it can not be treated the fluid forces only bythe static approaches. 2) The interaction effects of neighbouring cylinders are much com-plicated, and it must be accounted of the fixing conditions of cylinders, in upper side orin lower side. 3) The dominant frequency of the drag direction is in accordance withthe natural frequency of the test cylinder, but that of the lift direction is mainly controledby the frequency of Karman vortex.

This paper describes an experimental investigation of the spatial structure of turbulence ina free surface shear flow, carried out at the Nobi agricultural canal, using 4 current meters of apropeller-dynamo type. A convective process of turbulence is investigated through a techniqueof the space-time correlation, with and without frequency filtering, for the longitudinal componentof the velocity fluctuation.The experimental results are as follows. 1) Different turbulent spectral components of anopen channel flow are convected with different velocity, that is, the large scale disturbances nearthe free surface are convected more slowly than the small scale ones. 2) The departure of the fro-zen pattern in the period of the disturbance is remarkable for the disturbance of long period, but, in the same distance, it is remarkable for the disturbance of short period.

The hydraulic similitude to guarantee any scale model test for one-dimensional flowsin pipes and open channels can be derived from one-dimensional equations of continuity, energy or linear momentum in the control volume method of hydraulic analysis.Recently, the first author has derived the exact formulation of one-dimensional systemof equations of continuity, energy and linear momentum in the curvilinear orthogonalcoordinates from the original system in theoretical hydrodynamics, and the authors haveshown a special system of equations for the open channel flow in a rectangular channel.The results obtained indicate that the classical dynamic equation must be supplementedby additional terms concerning three-dimensional variations of transverse velocity andstage in the unsteady behaviour, which suggests the classical treatment for the hydraulicsimilitude of unsteady open channel flows should be modified. This paper treats withthe order effects of additional terms to the classical equation for the unsteady open channelflow and the derivation of new formulation for the hydraulic similitude of unsteady openchannel flows.Preliminary experimentations made in a laboratory test flume will also verify thetheoretical results and predict careful treatments for proceeding the hydraulic scale testwith distorted dimensions.

This paper deals with the mass transport in the laminar boundary layers developedon smooth and horizontal bottoms by standing waves in shallow water.By theoretical approach, the laminar boundary layer equations are applied to solvingthe oscillatory motion in the boundary layers caused by the standing waves. Approximatesolutions, obtained by the aid of the perturbation method describe the velocity of the 2ndorder approximation in the vicinity of the bottom and are applied to deriving the masstransport velocities in this layer.The theoretical results are compared with experimental data on the mass transportvelocities in standing waves in shallow water.

This paper describes the turbulence characteristies of curved flows on the basis ofthe results of velocity measurements by a small propeller type current-meter. Themeasurements were conducted in two kinds of 1800 curved open channels with 50 cm inwidth and different central radii of 50cm and 150cm each other under conditions ofsupercritical flows. The turbulence characteristics obtained from the statistical analysisof longitudinal velocity component are summarized as follows.The intensity and the length scale of turbulence decrease in the curved and thedownstream straight reaches except the outer part of the inlet region of the curved reachwith the smaller central radius. In the outer part of the region, the turbulence intensityincrease, but the r. m. a. of the velocity fluctuation are no more than that of the upperstraight reach and the turbulence scale also decrease. The decrease of turbulence inte-nsity and scale is due to the decrease of energy spectral density in the lower frequencyrange.

This paper deals with the mass transport in the boundary layer developed on smoothand rough boottoins by standing waves in shallow water of uniform depth.Measurements by means of dye tracer show that observed mass transport velocityprofiles in the laminar boundary layer are in good agreement with the theoretical valueexcept for low waves. However, for high waves, the observed mass transport velocityU on a smooth bottom is less than that predicted by the laminar theory as the bottomboundary layer becomes turbulent. These results indicate that at the inception of turbulencethere is a break from the laminar theory in which U is proportional to H2 (H: waveheight).In addition, the velocity profile on a rough bottom is discussed on the basis of exper-imental results.

This paper deals with the spatial structure of turbulence in free surface shear flows. The fieldmeasurements of turbulence were carried out in the Nobi agricultural canal constructed at mu-yama along the left side levee of the river Kiso, using 4 current meters of a propeller-dynamo type.The intensity, the skewness factor and the flatness fator of velocity fluctuations, the auto- andcross-correlation and spectra, the coherence and the phase-lag were analyzed from the record ofvelocity fluctuations in the flow direction. From these experimental data, some qualitative pro-perties of spatial structure of turbulence were revealed, that is, the turbulence element was widerspread in the free surface region, and the phase of turbulence near the free surface was in progresscompared with that near the bed. Furetheremore, the hypothesis of frozen turbulence by G. I.Taylor was good applicated for the turbulence in the flow direction.

Information about bottom friction is required to understand various phenomena suchas wave transformation and sediment movement in shallow water. The purpose ofthis paper is to discover experimentally the mechanism of bottom friction near thetransitional region from laminar to turbulent boundary layer under periodic gravitywaves. The experimental investigation was made by means of the direct measurementof instantaneous shear stresses acting both on smooth and rough bottoms. The ex-perimental results were compared with both the linearized theory on the laminar boundarylayer growth and the theory on the bottom friction in a turbulent oscillatory flowestablished by Kajiura.

The present paper treats the dynamic bending strains in a cylindrical pipe embeded in anelastic homogeneous surface layer with uniform depth to the base ground extending over the semi-infinite elastic half space during the passage of surface waves along the pipe axis.The results indicate that the motion of the pipe is influenced by acceleration of the surfacelayer, and that the bending strains are closely connected with wave lngth of incident waves. Andthe relative displacement of the pipe is very small, and the characteristic vibration of the pipe isnot caused.