This paper describes the performance of a vertical axis wind turbine with variable-pitch straight blades. Our aim is to get basic data to increase the efficiency of micro vertical wind turbine systems. The proposed variable attack angle mechanism has an eccentric point that is different from the rotational point. The main feature of the mechanism is to be able to change attack angles according to the rotational angles of the blades without actuators.We measured the performance of wind turbines with a flat plate, asymmetric and NACA63_4-221 airfoil sections by using an open circuit type wind tunnel. The wind turbine with variable-pitch straight blades has a directivity for the wind. It was found that the performance of the wind turbine is dependent on the angle of attachment, the amplitude of the fluctuating pitch angle, the number of blades and chord length of the airfoil. The efficiency of the wind turbine with NACA63_4-221 airfoil section is larger than that of the other wing section.

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The horizontal axis wind turbines are operated under skew inflow condition and it has tilt angle to keep the distance between tower and blade tip. Therefore, it is important to analyze the forces and moment of rotor with yawed and tilted inflow condition. In this study, the wind turbine was placed with yaw miss alignment or changing the distance between tower and rotor in a wind tunnel. Through measuring the forces and moments of HAWT with six-component detector, the characteristics of rotor performance with yaw and tilt angle condition and influence of tower position are considered.

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The use of the clean natural/renewable energy resources has been promoted in the power generation, as those scarcely emit greenhouse gases. The waterpower has larger energy density than the wind power and the solar power, and there are many hydraulic power stations. The large-scale station with a dam, however, is undesirable because such public works damage natural ecosystem in rivers andlor forests. To promote more and more the hydroelectric generation for the next leap, it is necessary to utilize effectively mini/micro/nano hydropower in coexisting with natural ecosystem. This research develops a new type hydroelectric unit utilizing the yawing motion of the submerged blades in rivers, irrigation channels, and so on. In this report, the concepts of the unit are explained, and the output characteristics are discussed experimentally using the trial model.

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The wind predictions around Mt. Akagi with meso-scale model WRF and local wind-simulation code NuWiCC were carried out. Numerical results with WRF suggested that the large-scale spatial structure with an active advection in the vertical direction play a dominant role. In addition, the behavior of predicted wind fields strongly depends on the governing equations used in the numerical model, i.e., the meso-scale model is suitable to predict the such wind fields, while the horizontal wind-field obtained with local-wind simulation code becomes uniform spatially, regardless of inflow condition.

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This report introduces an attempt for wind turbine using blades with circular cross section, although many wind turbines now has blades with wing section. The blades with circular cross section become profitable with strength, stiffness and manufacturing cost in comparison with wing type blades. They are not pure circular cylinders, but have grooves on their surface in long distance direction. A groove forces boundary layer transition on the flow, and that causes asymmetry flow around circular section. The blade with circular cross section produces lift. We performed some wind tunnel test for the blade with circular cross section. Wind tunnel test shows that maximum lift coefficient is 0.6〜0.8 at Reynolds number 1.509×10^5〜2.515×10^5 , and suggests that the wind turbine using blades with circular cross section is low speed high torque type.

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This report introduces an attempt for wind turbine using blades with circular cross section, although many wind turbines now has blades with wing section. The blades with circular cross section become profitable with strength, stiffness and manufacturing cost in comparison with wing type blades. They are not pure circular cylinders, but have grooves on their surface in long distance direction. A groove forces boundary layer transition on the flow, and that causes asymmetry flow around circular section. The blade with circular cross section produces lift. We performed some wind tunnel test for the blade with circular cross section. Wind tunnel test shows that maximum lift coefficient is 0.6〜0.8 at Reynolds number 1.509×10^5〜2.515×10^5, and suggests that the wind turbine using blades with circular cross section is low speed high torque type.

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For the improvement of rotor performance for the horizontal wind turbines, the winglets attached at blade tips have been attempted. It can move the shedding position of the tip vortices away from the blade tips to the tip of the winglets, which decreases the axial induced velocity in the rotor plane, leading to the increase of the rotor output. The similar effects can be expected in the sweepback rotor blades andlor rotors with coning angle for the output augmentation. The present paper describes the influence of sweep and coning angles of the rotor blades to the flow field around the rotor blade, and the blade load, which are analyzed by a panel method with free wake model. The results show the possibility of the performance improvement by adopting the rotor blade with sweep or coning angle.

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The sliding concentric cylinder technique has been discussed to evaluate the first normal stress difference of viscoelastic fluids. The entry pressure loss at the bottom of the bob was ignored in the previous study. In order to estimate the entry pressure loss, the three bobs were made. They have the same diameter but their length is different. The same technique of Berkley plot was applied in this study and therefore the effect of the bob length on the reactive force was measured. The evaluated N1 was close to the value predicted from the results measured by the rheometers. On the other hand, the result of N1 with the correction of the entry pressure loss was affected by the bob length. It seems that the validity is lacked in this result.

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An analytical method for the capillary entry flow of viscoelastic fluid is developed based on the boundary layer approximation to predict the transient behavior of flowrate and development of inflow region starting from at rest. Experiments are carried out for the start-up flow of a viscoelastic polymer solution driven by a constant pressure. The uni-axial elongational viscosity is estimated from the entry pressure loss of terminal steady flows. The inflow region length in steady flow is well predicted by the analytical method with a constant elongational viscosity thus obtained. While, the overshoot and delay of flow rate observed in the experiment are not reproduced at all. This may be attributed to the increase of the elongational viscosity due to strain thickening.

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A design for measuring planar elongation viscosity was considered. The apparatus consists of opposing nozzles through which the liquid is either sucked or blow out. The cross section of nozzle is square and two dimensional opposing flow is used to generate planar elongational flow. The elongational stress is estimated from a reaction force acting on the opposing nozzles. The planar elongation viscosity for CTAB/NaSal aqueous solution was measured by using this new technique, and it compared with the result which was measured by the optical technique. The measurement result shows qualitatively agreement, but quantitatively 10 times larger than the result measured by the optical technique.

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Flow visualization experiments on Barns effect in a one-sided cavity has been performed in order to develop the heat transfer augmentation technique in a cavity, where heat transfer is reduced for the case of Newtonian fluid. In this paper, the effects of expansion ratio and Weissenberg number in a low Reynolds number region on recirculation length formed in the downstream region of the cavity between ribs. The width of wide flow path and the length of the rib were fixed at 40 and 50mm, respectively, while solvent Reynolds number based on rib height was changed from 100 to 400. The rib height and cavity length were also changed in three steps, respectively. From the results, it is found that the recirculation length in the low Reynolds number range becomes much smaller than that in the case of Reynolds number of 2,400 reported by the previous study. This can prevent heat transfer reduction in the downstream region of the cavity. Then, this technique becomes more effective in low Reynolds number region. It is also found that the recirculation length depends not on expansion ratio but on Weissenberg number in low Weissenberg number region.

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The suspension which disperses solid particle changed reological characteristic substantially. Flow characteristic in a gap of hemisphere concentric spheres are studies for viscoelastic liquid contain fiber on suspensions. Rheological behavior of the suspension was studied prior to the flow situation, indicating shear thinning as well as viscoelastic character depending upon the concentration of the fibers. The flow field was observed to be the simple Couette flow in the gap space, but shown the offset from the simple Couette flow as the rotational Reynolds number is increased. It was found that the dependence of the gap width is substantial and Tayler- Gertrudis vortex was controlled by glass fiber.

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We observed liquids dripping out of an aperture at low Reynolds number using CCD camera, measured the mass of a drop and the velocity of falling drops, and estimated dynamic surface tensions. Reynolds number ranges from 1 to 200. The solutions tested in this experiment are AE solutions in water. A modeling of surfactant molecules was presented for predicting the normalized dynamic surface tension of surfactants. It was confirmed that the expression obtained by this model approximately agrees with the experimental values.

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ER characteristic in smecticA phase of a liquid crystal have been investigated utilizing a parallel-plate type rheometer. Since the smectic liquid crystal has a solid like property which is controllable with the electric field and temperature conditions, the strength of the structure in the SmecticA phase is experimentally examined from the change in yield stress under various conditions. It is found that the yield stress was depending on the current type of the electric field and the frequency of AC electric field. Moreover, the yield stress is only dependent on the electric field condition when the Smectic structure is grown, and the yield stress, i.e. the structure generated, is hardly changed by changing the electric field after. Larger yield stress is obtained with a rough surface of the electrode.

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Simulation of velocity profiles of electric-fields induced nematic liquid crystalline flows between parallel plates has been achieved using the Leslie-Ericksen theory, as the fundamental research on the development of liquid crystalline micro-actuators. To obtain continuous movement of the micro-actuators, the pulsated electric field is applied on the nematic liquid crystal cell. The various frequencies of the applied electric filed are examined to explore the effect of the frequency on the movement of the cell upper plate. Responding to the pulsated electric field the director angle increase and decrease repeatedly. The clockwise and counter-clockwise rotational motion of the director induces forward and backward movement of the cell upper plate. When the frequency is high, smooth movement of the upper plate is obtained, apparently.

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We propose a strategy for a micromanipulation method using SSFLC (surface stabilized ferroelectric liquid crystals). By adjusting the frequency of the applied ac electric field, the surface layers thet cannot follow an applied ac electric field are constructed in SSFLC. In addition, by applying a sawtooth wave voltage, net flow along the smectic layer is generated. The flow direction is reversed by changing the polarity of the sawtooth wave. Consequently, the particles dispersed in SSFLC can be driven bidirectionally along the smectic layer. The particle velocity depends on the temperature, amplitude and frequency of the applied voltage.

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For the melt extrusion process of a multi-layer film, it is well known that the encapsulation phenomena appears in the die and each layer thickness changes in the width direction due to the difference of rheological properties for each layered polymer. This process has been numerically analyzed by the finite element method with moving interface elements, but the failure of re-meshing occurred because of large deformation of mesh resulting from large deformation of interface. We developed the new analysis technique using a fixed mesh independent of interface change in the iterative calculation scheme and applied for the multi-layer flow in the die. As a result, we obtained successful solution when a sufficient resolution with a fixed mesh was employed.

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A local shear rate due to a local flow surrounding a small air bubble under a periodical oscillatory pressure field was derived theoretically, which is able to estimate an enhancement in removing the bubble from shear-thinning fluids. This estimation requires experimental data of changing bubble size over a cyclic period. Because the oscillation frequency was too high to record by the commercial video camera, we use a special technique. The pressure inside a closed test cell was controlled by vibrating a thin-film set on the fixed cell. We compared the observed rising velocities under oscillating pressure condition with a free rising velocity that was estimated from the shear viscosities and mean bubble sizes, which are measured by the strobe lighting technique. We also studied the bubble shape under periodical oscillatory pressure. In some cases, a cusped bubble was observed only when the diameter approached to its minimum size.

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Brownian dynamics simulation was performed for a polymeric liquid modeled as a suspension of model polymers consists of connected FENE dumbbells. Potential forces between a bead and another bead that belongs to another model polymer were introduced to simulate the effect of entanglement. Numerical simulations of simple shear flow qualitatively predicted typical rheology of polymer solutions. Moreover, the behavior of model polymers in a Poiseuille flow in a channel was computed. The present computation simulated entanglement of model polymers and predicted the distributions of bead and the length of model polymer due to the shear rate distribution in the channel.

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Three-dimensional bolus geometry was reconstructed from multi-angle 2D images of X-ray video fluolography. The developed method enabled free view angle for the flowing bolus. A mesh model was created from the digitized bolus shape, and was used for FEM analysis. The obtained swallowing pressure approximately agreed with the past result. Applying the same method to a liquid bolus, a mesh model was constructed to analyze the velocity and shear stress. Block fitting technique and data mapping method were used in the FVM analysis. Compression flow was computed for validation, and the results were agreed with the theoretical results for thrust force. In addition, this method enabled the analysis of complicated liquid bolus flow.

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Three dimensional finite element analyses on the blood flows in vessels with stenosis and aneurysm have been achieved using various blood fluid models, such as Casson, Carreau-Yasuda, and Bi-Viscosity models. The results of these models are compared with the results of the Newtonian fluid to explore the non-Newtonian effect on the blood flow. Since the blood flows are pulsative, the flow rate varies with time. When the flow rate is high, the blood flow exhibits Newtonian-like behavior. On the other hand, for the low flow rate case, the difference between the results of the models becomes remarkable, and the blood flow no longer shows the Newtonian-like behavior.

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Surfactant additives have been attractive as practical drag-reducing additives because they were not affected by the degradation due to mechanical shear action and they could apply to the circulatory system. There are only a few studies on the turbulent boundary layer flow of surfactant solutions, although a lot of studies for turbulent channel flow and pipe flow have been performed so far. The influence of drag-reducing surfactant solution on a turbulent boundary layer was investigated using a LDV system. LDV measurements were made for surfactant solutions of 65 ppm and 100 ppm. We compared turbulence statistics between water and surfactant solutions for understanding the detailed drag-reducing mechanism.

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Direct numerical simulation of a zero-pressure gradient drag-reducing turbulent boundary layer of viscoelastic solutions was performed using the constitutive equation models such as Oldroyd-B and Giesekus models. The distinct difference in turbulence statistics near the wall between Oldroyd-B model and Newtonian fluids is observed, as reported in the drag-reducing turbulent channel flow, while the difference between Giesekus model and Newtonian fluids is slight in this study. On the other hand, in the outer region, distributions of mean velocity and turbulence statistics for both Oldroyd-B and Giesekus models are similar to those for Newtonian fluids.

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Drag reducing solutions are usually viscoelastic fluids. But its elasticity is difficult to measure by conventional methods like a cone-and-plate rheometer. We propose a measuring method to evaluate the elasticity at high strain rates by measuring the jet thrust through capillaries and nozzles with a commercial electric balance.

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Decaying grid turbulence is experimentally studied. Three different kinds of surfactants (Alkyltrimethylammonium Chloride and Sodium Salicylate) in which the hydrophobic group lengths are changed as n=14, 16, 18 are used. We confirmed that the decay exponent of velocity fluctuation is -1 at initial period and it is -5/2 at final period. The viscoelastic feature of surfactants is studied by analyzing the bump of turbulence intensity and the PDF shape is analyzed.

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