In this study,it is clarified effect of center of flapping amplitude(CFA) for body angle on flapping flight without tail-plane.The average of body angle has negative correlation to CFA on flight of a flapping robot and two butterflies from results of observations for these flights.From this result,CFA is one of important factor for flapping flight.By using an equation of moment around flapping robot,it is considered that the body angle change is occurred by translation of application point of aerodynamic force due to CFA change.Moreover,the moment variation on CFA changing depends on point and direction of application of aerodynamic force and angle of attack.

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Flight organisms generate the lift according to the flapping motion.However,the mechanism of production of lift is not clarified sufficiently.So a lot of researchers studied the mechanism of production of lift until now.Therefore,it is important for production of lift to generate the vortex ring on the flight organism wings.However,the relationship between vortex ring and lift is not clarified.The purpose of the present study is to clarify the dynamic lift generated by butterfly wings.

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Wind damage in forest resource caused by strong wind can be increased after tree thinning.In this study,effect on wind resistance of forest depending on tree arrangement and method of the thinning was investigated by model experiment in wind tunnel.Atmospheric boundary layer was generated in the wind tunnel by the circle cylinder grid and the screen.Drag act on a tree in the model forest was measured in two types of tree planting configuration which were in-line and staggered arrangements.The result shows that wind resistance of in-line arrangement was higher than that of staggered arrangement.In the case of staggered arrangement,drag act on a tree in forest increased depending on the conditions of the distance between trees and of the wind direction.

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A sperm sorter using microfluidic system(MFSS) has been developed to solve sterility caused by abnormality in male sperm.To improve more separation efficiency of this device,it is necessary to know the behavior of motile sperm in detail.Under these backgrounds,the movement of the sperm in the microchannel was investigated in the present study.The previous study clarified that the modeling of the behaviors of motile sperm in the shear flow was necessary.Therefore,in the present study,we experimentally investigated the behavior of the motile sperm in the Taylor-Couette flow using PTV(Particle Tracking Velocimetry) method.The experimental results showed that the sperm velocity increased with the ascent of the shear stress and its direction is opposite to that of the flow.

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Cell electroporation using focused electric field by a micro-orifice in a thin insulating plate has potential to directly deliver the foreign molecules into a nucleus.This paper gives an insight into the mechanism of the direct delivery of the molecules by numerically analyzing the membrane potential of a nucleus and a cell trapped on the micro-orifice.The results show that the focused field enhances the buildup of the nucleus membrane voltage and may contribute to improve the molecular permeability of the nucleus membrane.

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An aneurysm is blood disease that is caused by blowing up of the artery wall.There is high probability of death if it is ruptured.Bypass surgery may be used when it is difficult to treat aneurysms by conventional treatment,for example when the aneurysm is located near ophthalmic artery that should keep the blood flow.There is not so much investigation about the bypass surgery from the point of the flow characteristics.Therefore,the purpose of this study is to investigate the flow-field within the aneurysm by visualization experiments and numerical analyses.As result of experiments it was observed that the flow rate through the branch was changed by the bypass flow and difference of the branch diameter.On the other hand,different flow pattern was also obtained at bifurcation area from numerical analyses that were performed by two-dimensional incompressible Navier-Stokes simulation.

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We have been developing a microporous covered stent as a newly device for cerebral aneurysm treatment.This stent has a porous film to control both embolization and rapid neointimal formation.It is expected that the neointimal formation becomes earlier by using much larger pores,but there is a possibility that the covered stent with large pare cannot embolize by increasing inflow from parent vessel.The purpose of this study is estimation of stent embolization and optimization of pore design to ensure compatibility between reliable embolization and controlling early neointimal formation,in-vitro experiment based on flow similarity low has been conducted by using a 2D parent vessel model with a side wall type aneurysm model.The flow visualization result shows that three kinds of flow pattern in the aneurysm were observed namely,viscous shear induced flow,pressure drop induced flow and those coexistence flow.According to PIV result,mean shear rate in the aneurysm after stenting was decreased to less than 1/10 of before stenting.

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Recently,pathogenesis of aortic valve sclerosis with aging is increasing with development of the aging of the population in Japan.It has been known that endothelial injury is the first step of valvular cholesterosis and the sclerosis.This study considered that some kinds of mechanical stress caused by blood flow e.g.both wall shear stress and structural tensile/compressive stress are one of the factors of endothelial damage.Therefore,in vitro experiment for blood flow was conducted by using a realistic model of human aortic valve and cardiovascular flow simulator based on wind-kessel model and three-dimensional velocity vector distribution and wall shear stress distribution on the model surface were measured by stereo PIV.As a result,swirling flow in a Valsalva sinus model caused by inflow from a part of the jet flow through the valve opening was observed during systole Large shear stress gradient was observed on the surface of the valve basis with valve deformation at the mid systole.

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Hepatocyte transplantation is one of the cell transplantation techniques for the certain diseases of the liver.It has considerable potential as an alternative treatment of solid organ transplantation.In particular,it is indispensable treatment to control ammonia metabolism for a newborn baby who has liver dysfunctions.It is important to investigate the mechanical property of the hepatocyte while medical transactions.In this study,collagenase perfusion method was used for cell separation.Damage of the hepatocyte in shear flow were measured using trypan blue solution with a micro channel.As a result,hepatocyte injury situation was observed with optical microscope.The destruction conditions of the hepatocyte were clarified and the optimal infusion condition of the hepatocyte transplantation was estimated.

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Airflow in an avian respiratory system was simulated to study effects of the compliance of air sacs on the flow passing through parabronchi during a respiratorycycle.The geometry of the avian respiratory system was expressed three-dimensionally but simplified anatomically.The mechanical behavior of the air sacs was expressed by a lumped parameter model described with pressure,compliance and flow volume.The results demonstrated that the flow in the parabronchi was driven by the pressure difference over the parabronchi.The pressure difference over the parabronchi was affected by the air sac compliance.The flow in the parabronchi was unidirectional at certain compliances of the air sacs.These results address the importance of air sac compliances in efficient respiration in avian.

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With regard to energy saving,it is possible to design and construct apparatus for simulating drag reduction by using experimental data.In this study,a drag reduction technique employing either drag reducing additives or drag reducing walls is explained.In addition,some existing experimental data on the characteristics of drag reducing walls used in laminar drag reduction are summarized.

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We studied the influence of a number of gas-liquid interface on the drag reduction effect by numeric simulation.Level set method was used for an analysis of gas-liquid interface.The analytic model is rectangular channel of height h = 5 μm and width w = 20 μm with two hydrophobic microstructures in bottom of channel.In this channel,we found that the liquid penetrates in the upstream of microstructure more than the downstream of microstructure.The velocity in upstream region of microstructure decreases,conversely that in downstream region of microstructure increases.The analytic results show that the drag reduction occurs due to air-liquid interface in microstructure.

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It is important to reduce skin friction drag for engineering.Hydrophobic or hydrophilic surface is known to be effective in skin friction drag reduction.However,these drag reduction mechanisms are not yet well understood.Therefore,we painted the hydrophobic paint and the hydrophilic paint on the various surface materials of flat plates with the various patterns,and drag of these plates were measured under such various condition.As a result,it was found that skin friction drag on a flat plate with surface material of cloth with a vertical stripes-pattern of hydrophobic and hydrophilic surface can be reduced more than 11%.

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Recently,there has been a growing interest to develop microscale devices that can manipulate and transport relatively small volumes of fluids.In this study,we investigated the influence of wall surface conditions and polymer addition on microchannel flow.We measured the pressure drop in microchannel flow for three patterns of channel height h = 100,50,20 μm.Tested channel surface roughness are Ra = 0.2,0.8,1.6 μm.The experiment showed that the pressure drop increased with increase of channel surface roughness as in the case of both hydrophilic and hydrophobic surface.For polymer solution,the pressure drop decreased in all roughness.Drag reduction rate was increased with the increase of surface roughness.

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Much research on small bubbles and complex liquids and their drag reduction effect has been reported.Few studies have focused on nanobubbles.Nanobubble mixtures for water and glycerol were passed through several sizes of capillaries,and the resultant coefficient of pipe losses,as compared with water and glycerol,were evaluated in this study.For small capillaries,the investigated coefficients were less than water ones.This phenomenon is considered in terms of interface behavior and attributed to the electrical interaction between an electric double layer and nanobubbles.The results of the present study suggest that the addition of nanobubbles to a liquid results in excellent drag reduction.

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Micro bubble has unique characteristics.One of them is drag reduction.The drag reduction of pipe flow has been studied with the addition of the surface-active agents and/or polymer.They may pollute the environment after disposition,therefore the limitation occurs in the using them for the practical fractional drag reduction of pipe flow.Micro bubbles generated from air have no possibility of such pollutions.In this study,the frictional pressure drop is measured in vertical pipes.When micro bubbles are generated by the pressurized dissolution method,the drag reduction is not remarkable.On the other hand,when micro bubbles are generated by the shearing flow method,the drag reduction clearly occurs.The effects of void fraction and Reynolds number on the drag reduction are not clear.

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Excess counterion enhanced the drag reduction in high shear flow.This enhancement was saturated when the molar concentration ratio of the counterion to surfactant was higher than ten.In the saturated condition of the counterion,the plots of drag reduction rate(DR) against wall shear stress was independent on the tube diameter over DRmax.When the flow rate increased from the start of drag reduction to its maximum,the plots of DR against Rew were reduced to a single curve for the small tubes of 0.9 and 2 mm.The surfactant of 1500 ppm was used with the counterion of ten-times higher molar concentration,and DR of 30 % was obtamed at the wall shear stress of 10^3 Pa,which corresponded to the shear rate of order 10^6 s^1.The surfactant solutions with excess counterion is effective in the application of high shear drag reduction.

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There are a few studies on the drag-reducing effects of nonionic surfactant solutions which are non-toxic and biodegradable,while a lot of investigations for catiomc surfactant solutions have been performed so far.We investigated effects of the molar ratio of nonionic surfactant,oleyldimethylammeoxide(ODMAO),to additives such as Salicylic sodium,Salicylic acid,and Cuminic acid on the drag reduction by measuring the pressure drop and flow rate in the circuit pipe flow.It is found that the drag-reducing ability is largely dependent on the kind of additives and the molar ratio.

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It is known that surfactant additives in wall-bounded turbulent flows yielded the significant drag reduction.In this study,we conducted PIV measurements for a turbulent boundary layer with noniomc surfactant solution injection from wall surface.The noniomc surfactant,AROMOX,which mainly consists of oleyldimethylamineoxide(ODMAO),is used.First,we compared turbulence statistics from PIV measurements with those from LDV measurements for confirming the accuracy of the present PIV results.Then,we investigated the relation between the drag reduction ratio and turbulence structures near the wall.

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Reducing pipe friction by adding a drag reducing agent has attracted interest as a means to reduce energy consumption.In addition to reducing drag,drag reducing agents should also have a low environmental load and conserve natural resources.However,no drag reducing agent currently satisfies both these conditions.In this study,drag reduction due to nata de coco suspensions with small environmental loading was investigated.The drag reducing effect was evaluated by measuring the pressure drop in circulating pipeline system flow.Nata de coco suspensions reduced drag by up to 25 %,and the drag reduction of nata de coco suspensions was not affected by the mechanical degradation unlike that of typical polymer solutions.

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Drag reduction effect by traveling wave-like wall deformation in a fully developed turbulent channel flow is revealed by means of direct numerical simuation.In the cases of downstream traveling wave,three different behaviors are observed depending on the parameters:ordinary drag reduction,stable relaminarization,and unstable relammarization.In the stable relaminarization case,velocity fluctuations are found to completely vanish.

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A system for feedback control of pulsating pipe flow has been experimentally examined for friction-drag reduction in a turbulent pipe flow.The rotating speed of a centrifugal pump was changed for generating the pulsating flow.A magnetic flow meter and a pressure gauge are employed for measurement of normalized pressure gradient.The rotating speed is gradually increased while the normalize pressure gradient is over a threshold value 0.018 for re-laminarization.It is found that the wall shear stress is decreased by about 5.9% when the cycle-averaged friction Reynolds number based on the friction velocity,the radius and the kinematic viscosity was set to be 177.

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Experimental investigation of the flow structure of modified viscoelastic drag-reduced channel flow by PIV.In order to modify the flow,water was dosed to the drag-reduced flow from the whole surface of the channel wall.The result shows that characteristic flow structure was observed.In the modified drag-reduced flow,drag reduction rate decreases,a quite strong peak of streamwise velocity fluctuation was obtained in the near-wall region and additional peak was also observed in the region away from the wall.Considering the results of Reynolds shear stress, this modified drag-reduced flow can be categorized three regimes from the channel wall on the boundary of the peak position of the streamwise velocity fluctuation.

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This paper investigated turbulent suppression caused by the thermal stratification in horizontal pipe.The present study finds that when the pipe flow becomes stratified,the mixing in vertical direction is suppressed and pressure drop decrease.Therefore,we investigated the tendency to decrease the pressure loss of pipe flow by changing the flow rate of upper-hot flow in a pipe.Experiments were performed using the differential pressure meter to measure the pressure drop.The experimental results show that the reduction of pressure drop is more remarkable in the stratified condition that velocity difference between upper and lower flow is high.

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We have carried out experiments to measure velocities of turbulent water flow over a wavy plate with symmetrical ridgelines on the bottom of a shallow open channel at a high Reynolds number.This plate mimics the folded skin of fast-swimmmg dolphins.Also,we have measured total drag acting on the test plate by the flow.Wall-shear stress is evaluated from the gradient of mean velocity on the plate surface.The pressure-drag is calculated from the difference between the total drag and friction drag.The results show that a certain reduction of the wall-shear stress occurs particularly near the side of the plate.Our results indicate that an increase in the pressure drag is reduced.

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We have investigated turbulence of surfactant solution in a precessing sphere by means of laboratory experiments(particle image velocimetry).A weak precession(the precession rate Γ = 0.1) of spherical vessel sustains strong turbulence of the confined fluid.So we compare mean velocity fields of turbulence of water with those of surfactant solution for the fixed precession rate at Γ= 0.1 and different Reynolds numbers.It is then shown that turbulent structure is drastically changed in the inner region of the sphere,and that this turbulence modulation is stronger for higher Reynolds numbers.

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To use wind energy resources for power generation,the wind turbines must be installed in high wind potential site.To estimate wind condition on complex terrain,such as Japanese topography,it is important to clarify the flow around complex terrain In this research,flow field over the two-dimensional hill is investigated experimentally in a wind tunnel with boundaiy layer profile and two lands of turbulence intensity.The flow around hill model is measured by PIV system.In addition,ground surface pressure is measured.This measurement clarifies the influence that turbulence intensity,hill slope angle and vegetation give in flow over the hill.As a result,the difference of turbulence intensity of inflow affects to shift separation point,reattachment point and ground surface pressure.

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In recent years,constructions of wind farms are promoted.The "wind farm" means a large-scale wind power generating facility and has many wind turbines in a site.In wind farms,wind passed through an upstream wind turbine,it is called "wake",may flow in a downstream wind turbine depending on the wind direction.In the wake,wind velocity decrease by energy extraction and wind turbulence increase.The wake causes power reduction and shortening of the downstream wind turbine life-span.We analysed the wake velocity field of horizontal axis wind turbine by using panel method.The comparison between analysis results and experimental data shows approximately agreement in the near wake field.We considered effects of yaw-misalignment and deduced wake deflection angle.

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The operational control of the wind turbine,such as blade pitch control and/or speed control of the turbine rotor,is one of the useful methods to reduce the temporal variation of wind turbine output.For the optimization of the control method,the response of turbine performance has to be clarified with respect to the changes in operational condition.We have examined the effects of wake inertia on the response of turbine performance when the blade pitch and the rotor speed are temporally changed under stationary inflow condition by using numerical calculation.The calculated results provide relationship between the responses of the wake-induced velocities on the rotor plane and the aerodynamic performance.

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This study investigated the influence of a wind turbine tower on the wind velocity distribution in the wake of a wind turbine operating at a low tip speed ratio.Large-eddy simulation(LES) of the wind flow around the wind turbine was performed using an actuator disk model for the rotor and by explicitly resolving the tower and nacelle.In addition,LES with no tower was performed.With regard to the streamwise component of the wind velocity in the wind turbine wake,the LES with tower reproduced the asymmetric distribution in the lateral direction,which was observed in a wind tunnel experiment,while the LES with no tower produced symmetric distribution.

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A feasibility study of feedback control for mitigating periodic flow separation on NACA0024 airfoil was constructed by using dielectric barrier discharge plasma actuator(DBD-PA) and fiber Bragg grating flow sensor(FBG-FS).Towards applying these devices to small wind turbines,transmission of Bragg wavelengths detected by FBG-FS are tested by using a fiber optic rotary joint(FORJ) from rotor to stationary location Non-contact power transmissions for driving DBD-PAs were also tried by using opposed ferrite pot-cores from stationary location to rotor adversely.

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Dielectric barrier discharge(DBD) plasma actuators were applied to the horizontal axis wind turbine to improve the aerodynamic performance.The axis torque and pressure distributions on the wing of the wind turbine were measuremed to evaluate the effect of flow control by plasma actuators.The axis torque of the wind turbine improved up to approximately 20% at the experimental condition of U_∞=10m/s,β=40deg and rotational speed=174rpm.The performance of the plasma actuators depended on the frequency of unsteady actuator operation.The difference of the flowfields between plasma on and off was also visualized by the tuft.

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A good physical understanding is essential in order to provide an accurate estimation of the dynamic wind loads required for the optimal mechanical design to improve the performance of wind turbines.While a number of studies have been conducted in the recent years to investigate wind turbine wake aerodynamics,very few experimental investigations can be found in literature to provide detailed field measurements.The objective of this research is to develop stereoscopic PIV system for large-scale industrial wind tunnels and to apply the system to unsteady flowfields of Magnus wind turbines with spiral fins.

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An aerodynamic optimal design method for wind-lens turbine using the Genetic Algorithm has been developed.In the present method,the aerodynamic design for the wind-lens turbine rotor is based on an axisymmetnc viscous flow analysis and a two-dimensional blade element design.The present optimal design method is able to search for the optimal wind-lens and rotor blade shape simultaneously.This coupled design method of turbine rotor and wind-lens has achieved to generate high performance wind-lens turbines.Three-dimensional Reynolds averaged Navier-Stokes(RANS) simulation shows that the new wind-lens turbine designed by the genetic algorithm design method is superior to conventional one in the total performance.

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Renewable energy resources including wind power generation are receiving more and more attention these days.In Japan,however,because of small land area,steep terrain,and population concentration in plane area,it is difficult to construct massive wind farm on land.The concept of offshore wind farm can overcome this problem.We have developed a wind turbine with a brimmed diffuser(Wind-Lens Turbine) that has an additional hollow structure(Wind-Lens) consists of a diffuser shroud and a ring-shaped brim at the diffuser exit periphery To install the Wind-Lens Turbine in an offshore wind farm,we need to size up the Wind-Lens Turbine.This time,we propose a multi-supporting structure appropriate to a floating platform and investigate the effects of multi-supporting structure on the wind turbine performance and resistance for the Wind-Lens Turbine.We make some wind tunnel experiments and numerical simulations.

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The research proposes a flagmill,which is a new wind power generator utilizing the flutter of a flexible sheet.The sheet is simply supported at the leading edge by a supporting pole which rotates around its axis.The flutter of sheet causes the rotational oscillation of the supporting pole around its axis.The rotational oscillation of the generator axis connected to the supporting pole induces the electric power.In the present research,the experiment and the two-dimensional stability analysis were performed.The flutter behaviors and power generation characteristic were investigated experimentally and analytically.Flutter flow speeds,modes,frequencies were investigated by varying uniform flow speeds,sheet lengths,and compared with the analytical results.The results mdicated that the angular amplitudes are the most important for the power generation and accordingly the first mode can generate the larger power than the second one.

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We propose a new idea of generating power with water in a household by micro water turbine settled in the pipe line in a house.We conducted experiment with a micro water turbine having 100 mm diameter blade.By using the experimental data of the power,we calculated mean power in a month at various cities in Japan when we settled the micro water turbine in a house.Although our used micro water turbine in the experiment has small energy efficiency,we can obtain about 50 W in a month.If we improve the micro water turbine,we can expect the possibility of using a micro water turbine in a household with generating more power.

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The aim of this study is to develop an ultralow-head water turbine for an open channel,such as an irrigation channel,in order to effectively use hitherto unused hydropower energies.By focusing on a cross-flow runner,we eliminated the casing and used the application as a water turbine(undershot-type cross-flow water turbine) for an open channel.We investigated the effect of flow rate on the internal flow of the water turbine by an experiment and a CFD analysis.As a result,the following facts became clear.At a large flow rate,water region is wide at the outer and inner circumference of a runner.Moreover,the influence that a shock loss gives to water turbine efficiency is large.

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A flotation thickening method under decompression is one of the thickening methods of activated sludge in sewage treatment plants.The new method named as "the sludge supply after decompression" was proposed by one of authors.In the present study,the flotation thickening characteristics,that is,effects of MLSS(Mixed Liquor Suspended Solid) of activated sludge and absolute pressure in a vessel on height of supernatant liquor and treatment time were investigated using this method.As a result,height of supernatant liquor increased rapidly at first and then approached a constant with treatment time.Final height of supernatant liquor increased with decreasing absolute pressure,and decreased with increasing MLSS.Finished time of thickening did not depend on MLSS,but increased with absolute pressure.

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Using a hollow fiber and RO membrane module currently being used in reverse osmosis,we performed a pressure retarded osmosis(PRO) power generation.I analyzed by simulation performance and the flow at that time.It was found that significant flow distortion in the module.Osmosis flow was less about 10% of the water flow.

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In this study,in order to enhance the performance of Wells turbine for wave energy conversion,the effect of 3-dimensional airfoil on the turbine characteristics has been investigated experimentally by model testing under steady flow conditions and simulated numerically by quasi-steady analysis under sinusoidal flow conditions.And then,the performances of Wells turbine with 3-dimensional airfoils have been compared with those of the original Wells turbine,i.e.,the turbine with 2-dimensional airfoils.As a result,it has been found that the performances of Wells turbine with 3-dimentional airfoils depend on the blade profile at tip.

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A twin unidirectional impulse turbine has been proposed in order to enhance the performance of wave energy plant.This turbine system uses two unidirectional impulse turbines and their flow direction is different each other.However,the turbine characteristics have not been clarified to date.The performances of a unidirectional impulse turbine under steady flow conditions were investigated experimentally by using a wind tunnel with large piston/cylmder in this study.Then,efficiency of the twin impulse turbine have been estimated by a quasi-steady analysis using experimental results.

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In order to develop a novel air turbine suitable for OWC based plant,a straight-bladed vertical axis turbine for wave energy conversion has been proposed in this study.Performances of the proposed turbine under steady flow conditions have been investigated experimentally by using a wind tunnel in this study.The tested rotor has some straight blades with a profile of NACA0018,a pitch diameter of 472mm and a width of 0.490m.

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A wave power generator with an impulse turbine is installed in the breakwater and consists of the air-chamber,turbine,generator and safety devices.The purposes of this paper are to construct the design method.As for the motion of water inside the air-chamber,that is,oscillating water column(OWC) is solved by the eigenfunction expansion method.The characteristics of turbine and OWC for irregular wave are solved by assuming the Gaussian distribution for the probability density of the flow rate of turbine.The time average turbine outputs are calculated by setting the limit of the rated power of an electric generator.The initial design decides the turbine size,the rotational speed and the rated generator power from calculation results for the several wave conditions.

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The purpose of this paper is the study for the respondence of float structure of a point absorber for the wave periods.The goal is to find the method to optimize the float structure for the wave periods.First,the normalized kinetic energy for various float structures under regular wave conditions with various wave periods was compared by solving the movement equations with the numerical methods.The diameter 25 m structure in 6s wave period indicated the peak kinetic energy.Second,the normalized kinetic energy for various float structures was compared under irregular wave and regular wave with 6s wave period.The normalized kinetic energy in irregular wave was smaller than regular wave.

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The purpose of this study is the development of the assessment tool for the wave energy converter.The target is the two body system,and one of the goals is the dynamic analysis of the system in three dimensional space and in the time domain.This paper presents the summary of the input wave setup and the dynamic analysis method for the system.The regular and irregular wave should be defined according to the Pierson-Moskowitz spectrum,JONSWAP spectrum,the measurement or simulation of the sea state where the system would be installed.The three dimensional movement equations for each parts should be defined and solved in time domain with the numerical methods.The simulation for the regular wave and irregular wave was carried out.

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Vortex structure in the wake behind surface mounted rectangular plate with sway motion and flow-induced vibration was experimentally investigated by using Particle Image Velocimetry(PIV) measurement.The flow structure in the downstream region of the plate changes with the phase of the vibration.Therefore,the present investigation focused on the characterization of vortex structure using the phase-averaged method; where the largest and the smallest amplitude of vibrations were detected by light sensors,and then the vibration phenomenon was captured using PIV system.Contour maps of velocity,vorticity and flow pattern were used to characterize the flow structure and thus using all those results,three-dimensional vortex structures were evaluated.

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