Mathematical analysis of isothermal and thermo elastic problems is developed under plane axisymmetric condition for a cylindrically anisotropic, inhomogeneous elastic hollow circular plate. We assume that material properties such as Young's moduli, coefficients of linear thermal expansion, and thermal conductivities have cylindrical anisotropy and inhomogeneity in a form of a power product of radial coordinate. We formulate fundamental equations of thermoelasticity under plane axisymmetric condition for a cylindrically anisotropic, inhomogeneous elastic solid. We derive analytical solutions of displacement, stresses and temperature change for boundary value problems of a uniformly pressurized hollow circular plate on boundaries, of a plate rotating at a constant angular velocity about its center, and of a plate subjected to uniform heat supply by surrounding media on boundaries. Numerical calculations are performed and numerical results are shown graphically. We discuss effect of interaction between cylindrical anisotropy and inhomogeneity on isothermal and thermo elastic behavior of the plate.

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We consider an axisymmetric elastic contact problem of a transversely isotropic layer which is bonded to a rigid foundation. The upper surface of the layer is smoothly indented by a flat-ended circular rigid punch. The problem is reduced to an analytical and exact solution of an infinite system of simultaneous equations utilizing a method of expressing a normal contact stress on the punch as an appropriate series function with a singularity at the punch edge. Convergence can be achieved using 8 terms of the series. Numerical results are obtained to examine the effects of the layer thickness and material anisotropy on stress fields.

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A generalized elastic-plastic-viscoplastic constitutive equation is proposed which enables us to express dynamic reloading and dynamic reverse loading processes. In both processes, an elastic straight line, a static curve and static Bauschinger stress are generalized. Next, an elastic-plastic-viscoplastic constitutive equation for a one-dimensional bar is derived from the proposed generalized one, and equations of theoretical propagation speed are shown in the bar. Moreover, effects of pre-strain are made clear on stress-strain relations and on stress wave propagation speed-strain relations produced by dynamic reload and dynamic reverse load. In addition, it is also shown that dynamic Bauschinger effect is predicted by the proposed elastic-plastic-viscoplastic constitutive equation.

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The reinforced concrete slabs of steel road bridges directly support the wheel loads of large vehicles. The maximum load-carrying capacity of the slabs is usually evaluated by a punching shear load-carrying capacity. With the objective of clarifying the punching shear load-carrying capacity of the slabs under running loads, the authors conducted tests under running loads on the three types of test specimens with different compressive strength of concrete, quantity of reinforcements, and effective depth. As a result, the authors proposed a punching shear dynamic model in the ultimate limit state and an equation for calculating the punching shear load-carrying capacity based on the maximum load-carrying capacity and the strains in reinforcements, and evaluated the agreement between the experimental values and the theoretical values calculated from the equation.

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The Timoshenko theory is usually used in the vibration analysis of a beam because it can yield a relatively good approximation in the high-frequency domain. This theory uses the so-called Timoshenko coefficient to couple the bending and shear deformations. This coefficient is calculated using the shear deformation distribution within the cross section that arises from the bending deformation of a beam. The shear deformation distribution is calculated based on certain assumptions. In this study, we reexamine Cowper's theory that introduces the least assumptions in computing the Timoshenko coefficient in the view point of dynamic behavior. The relationship between the Timoshenko coefficient and the dispersion relation is investigated. The evaluation of the shear stress distribution within this cross section is attempted using numerical simulation. Finally the effect of the Timoshenko coefficient on the wave propagation analysis of a beam is examined.

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This paper discusses influence of uncertainty in microscopic material properties on homogenized elastic properties of unidirectional fiber reinforced composites. Since variation in homogenized material constants of composites is sometimes caused by some kinds of microscopic uncertainty, multiscale stochastic response analysis for investigating a relationship between uncertainty in microscopic properties and macroscopic variation in homogenized material properties will be needed. In this paper, the Monte-Carlo simulation with considering the uncertainty in material properties of microstructure is performed.
As an example, the influence of the microscopic uncertainty of a unidirectional glass fiber reinforced plastic plate is investigated. Also, a difference between the results of stochastic analysis obtained by several classes of a homogenization technique is investigated. Some remarkable influences, for example, large variation of homogenized Young's modulus in transverse direction and of the homogenized Poisson's ratio in transverse plane caused by stochastic variation of Poisson's ratio of resin, are found in the result. These results indicate necessity of a detailed three-dimensional multiscale analysis for investigating a stochastic response of a homogenized elastic property to microscopic uncertainty in a composite material.

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In order to develop damage detection method for a reinforced concrete (RC) structure using an impact hammer excitation, some indices based on Fourier spectrum of a response accelerogram were analyzed. Two test pieces of a RC beam were used: one has sufficient shear reinforcement and the other not. To cause nine stages of damage, a test piece was simply supported and vertical downward forces were loaded. At each damage stage, an impulse excitation was applied and the response acceleration was measured. It was revealed that an index using phase difference spectrum showed fairly good correlation with damage by which bending stiffness was reduced although the index used no information on excitation force. Between the two test pieces, clear difference of the correlation was not observed possibly because bending cracks proceeded for both test pieces.

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With the objective of clarifying the dynamic characteristics of ultra high strength steel fiber reinforced concrete (hereinafter referred to as the UFC) beams, the authors conducted static-load and constant running-load tests on the UFC beams having five different depths. The results show that although the flexural load-carrying capacity of the beams under constant running loads decreased by about 4% of that under static loads, the capacity does not decrease significantly due to the bridging effect of steel fibers mixed in the UFC. The distance of the neutral axis from the top edge of the UFC beams having a height of H in an ultimate state was 0.19H and 0.23H under the static and constant running loads, respectively. The ultimate flexural load-carrying capacity calculated by applying the distance of the neutral axis is in good agreement with the experimental flexural load-carrying capacity.

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In this paper, the theoretical bifurcation analysis, numerical dynamic analysis of a folding truss with singular problem is looked at allowing for geometrical non-linearity and contact between node and node of the pantograph on the concept of multi-folding microstructures (MFM) which have cellular micro-structures. The experiment looked at the behaviour of a pantograph truss under loading and based on the principle of multi folding mechanism. The analysis based on bifurcation theory is discovered the theoretical equilibrium solutions with multi singular points of structural instability. Many equilibrium paths are identified during the folding process. The primary path has global structural instability and the bifurcation paths become local instability at bifurcation point.

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The design indicator is not necessarily provided systematically with adaptive control algorithm when assembling vibration control systems for building construction and in consequence obliged to follow after empirical rules. Present study aims at accumulating the basic properties necessary for designing adaptive composition with state variable filters to give circulated signal information and active on-line loops sustaining adaptive organization. In the simulation analysis, target conditions are firstly set up tight without reference models to arrange objective signals calm. The second situations are prepared with relaxant objective setting on reference signals to investigate the working of target models.

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Changes in dynamic characteristics of a steel frame membrane structure were estimated during construction. Effects of membrane on the dynamic characteristics, especially on damping coefficients, were clarified from ambient response and free vibration by human excitation. It was quantified that membrane raised damping coefficients by an average of 2 %. Increase of damping coefficients after membrane installation, however, depended on the natural frequency. Lower modes tended to gain more additional damping coefficients than higher modes.

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In this paper, we examine a design method of robust stabilizing modified PID (Proportional-Integral-Derivative) controllers for single-input/single-output plants. PID controller structure is the most widely used one in industrial applications. The plants of which the PID controller is applicable are restricted. Yamada and Hagiwara proposed a design method of modified PID controllers such that modified PID controllers make the closed-loop system for any unstable plants stable. However, no method has been published to guarantee the robust stability of PID control system for any plants with uncertainty. In this paper, we propose a design method of robust stabilizing modified PID controllers for any plants with uncertainty.

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Damping vibration experiment on an actual shell structure (a steel framed conical shell) was carried out to clarify damping characteristics of the shell structure, and also to aid in preparing a data base on damping ratios of shell and spatial structures for use in dynamic response analysis. The experimental methods are the microtremor observation, impact vibration test and the vibration test by human power. The analytical methods for evaluating damping ratios are the half-power method, the random decrement technique and so on.

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Building No. 1, No. 2 and No. 3 at the Funabashi campus of Nihon University were built around the same time, and these buildings were built as 4-story earthquake-proof structures with the same structures and foundations1),2),3). After the structure, earthquake-proof reinforcement (Building No. 2) and seismic isolation retrofit (Building No. 3) were carried out to further improve their safety, and these are now an earthquake-proof structure (Building No. 1), a seismic strengthening structure (Building No. 2) and a base isolated retrofit structure (Building No. 3). To evaluate how the damping ratio of a building is affected by reinforcement and repair work on existing buildings, we measured and then compared the damping ratios of these three buildings. First, the velocities of these three buildings were determined based on microtremor observation and vibration experiment by human powered physical manipulation (i.e., people generated the vibration physically applying a force to the buildings) were measured by the velocity detectors on the ground, in the basement, on the second floor and fourth floor of each building. Then, the damping ratios were calculated by using the random decrement technique (RD Method). Damping ratios in each building have been compared, and differences of damping ratios by reinforcement work have been considered.

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Recently, buildings with an isolation device installed in middle story have been constructed. However, an adequate isolation layer level in height of a mid-story isolated building has not been established, and this causes a restriction on design of a plan of a mid-story isolated building. To reduce this restriction, semi-active controlled systems are compared to observe response characteristics. Regarding a control law, velocity feedback based on bilinear optimal control is used. Based on time history analysis with a 30-DOF system, response differences with respect to a position of an isolation layer is studied. It is observed that semi-active control scheme can be used to reduce the absolute acceleration of a roof and the deformation of an isolation layer. On the other hand, much attention must be paid to behavior of a lower structure under seismic excitation in design.

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The present authors have already clarified that the flexural moment due to the vertical seismic force ignored hitherto as an additional load besides the primary one by the horizontal seismic force is able to be a trigger of the collapse of a kind of bridge pier.The previous paper dealt with the protective basement region for the column and/or the highway bridge pier, determined on the basis of the design concept of the flexure-shear failure transition steel ratio; that is to say, the protective basement region has been formularized for the diagonal shear force as to the bridge pier. The present paper has made the necessity of stabilization from the viewpoint of the coefficient of horizontal subgrade reaction clear, considering the frequent phenomena of flexural failures of the foundation piles in the ground in recent years; in addition the impulsive reflected tensile stress wave generates the tensile failures across the sections of bridge pier and foundation pile. This paper lays emphasis on the impulsive compressive force and the successive reflected stress wave due to the huge seismic motion, the strengthening of bridge pier and/or foundation pile, and the soil stabilization in order to protect the flexural break of pile.

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Blade Vortex Interaction (BVI) noise of helicopter is predicted by using CFD analysis based on three dimensional Euler equations and subsequent acoustic analysis. In the CFD analysis, Beddose generalized wake model is used to prescribe the geometrical position of tip vortices in the wake, and Lamb-Oseen model is used to consider the vortex dissipation in order to avoid overestimation of BVI noise which sometimes occurs when the dissipation is not considered in the model. Lamb-Oseen model simulates the vortex dissipation by enlarging the core radius and attenuating the swirl velocity of vortex. The calculated sound pressure shows adequate decrease of BVI noise peaks as well as the reduction of small fluctuations compared to the no dissipation result. In consequence, the use of vortex dissipation model like Lamb-Oseen model is effective to improve the quality of calculation by avoiding the overestimation of BVI noise and by reducing the unrealistic fluctuations in the sound pressure calculation.

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The experiments are conducted to reveal the flight performances of samaras in transverse winds by use of the blow-down wind tunnel. Samara samples are taken from a maple Acer crataegifolium and a tulip tree Liriodendron tulipifera. Samaras are found to set to auto-rotation from rest in shorter time in transverse winds than no wind. In some cases of transverse-wind experiments, lift force grows significantly larger than lift in free fall. The results show that in transverse winds samaras can fly further than conventional estimates based on terminal velocities using the vertical wind tunnel.

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Field measurements have been performed to investigate wayside low-frequency noise from a high-speed train. The measurements indicate that the observed low-frequency sound consists of three types of noise source mechanism. Pressure variations around the nose and tail parts of the train generated by train passing, low-frequency acoustic pressure waves aerodynamically caused by the train itself and viaduct structure-borne sound. The higher-speed region measurements show that the major formidable sound source of the low-frequency noise is attributable to aerodynamically generated unsteady noise, which is analogous to a line source. In order to understand acoustic source mechanism for the turbulent boundary layer, which is a main candidate of the line source, laboratory measurements using an axisymmetric model have been performed. The model experiment does not generate viaduct structure-borne sound. The results indicate qualitative agreement with the aeronautic noise measured in the actual field.

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Several equilibria of self-interacting fluids are formulated by variational functionals. In the self-gravitating fluid, this is done by the total mass and the total energy functionals, and then the dynamical stability of the equilibrium is derived from its linearized stability. Next, the quantized condensation is shown as a critical phenomenon, using the scaling invariance of these functionals. Similarity to the Smoluchowski-Poisson equation is discussed, and then the effect of thermal radiation is studied.

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Lattice Boltzmann analysis of the microvascular constriction flow after the partial replacement of red blood cell (RBC) with liposome-encapsulated hemoglobin (LEH) was performed with the aim of predicting the effect of LEH on primary pulmonary hypertension (PPH). Two models were considered - a normal model and a PPH model. In the case of only RBC flow, we revealed the relation between the constriction width in the PPH model and the vascular resistance. On the other hand, after RBC-LEH replacement, the vascular resistance decreased and the total oxygen carrying capacity increased. Furthermore, the changes in left ventricular pressure (LVP) and right ventricular pressure (RVP) were investigated using a simple circuit in which systemic circulation and lung circulation were connected in series. When the symptoms of PPH appeared in the lung arteriole, the RVP increased noticeably, while it decreased substantially upon RBC-LEH replacement.

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The stability of barotropic flows on a rotating hemisphere with the rigid boundary along the meridional lines, is studied under several wind-forcings, which bring about four-gyre flow patterns. This flow may be a correspondent on a rotating sphere to the two-gyre flow on the β-plane, which has been studied so far as a model of the westward intensification. As the wind-forcing is increased, an oscillating instability arises from the steady flow solution of westward intensification, without a preceding pitchfork bifurcation often observed in the β-plane. The critical magnitude of the forcing wind is not a monotonic function of the size of the middle gyres.

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In order to elucidate the aerodynamic characteristics of arrows, which have a marked effect on their flight, two 10-mm-diameter and 750-mm-long cylindrical models are tested in a low speed wind tunnel with the JAXA 60 cm magnetic suspension and balance system. The two models have different nose shapes. One has a blunt cylindrical nose and the other has a cone-shaped nose. Drag and lift were measured at flow speeds ranging from 8 m/s to 45 m/s. Test results obtained for the cone nose model show that the drag coefficient increases rapidly with increasing Reynolds number in the range from 0.82 million to 1.38 million due to a boundary layer transition and also show the drag bucket in the relation of drag coefficient versus incidence at a Reynolds number of 0.65 million, which is popular in laminar airfoils. The reasonable data sets obtained suggest that it is possible to measure aerodynamic characteristics of ultra fine slender bodies, such as arrows, with the system.

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To obtain the optimal shape of a 3D object minimizing the fluid surface force, an adjoint variable method based on the variational principle is formulated and applied to the finite element method. This method is a type of sensitivity analysis (the sensitivity is the gradient of the Lagrange function with respect to spatial coordinates), and is based on the calculus of variations. The constrained optimization problem of the cost function is converted into an unconstrained optimization problem of the Lagrange function by introducing Lagrange multipliers called adjoint variables. The optimality condition of the adjoint variable method consists of the state equations, the adjoint equations, and the sensitivity equations. The equations for reducing the fluid surface force under a constant volume condition are formulated. By using the 3D shape optimization system, the surface force of a object located in Reynolds number 1000 can be reduced by about 57.6% .

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The motion of assemblies of point vortices in a periodic parallelogram can be described by the complex position z_j(t) whose time derivative is given by the sum of the complex velocities induced by other vortices and the solid rotation centered at z_j. A numerical simulation up to 100 vortices in a square periodic box is performed with various initial conditions, including single and double rows, uniform spacing, checkered pattern, and complete spatial randomness. Point process theory in spatial ecology is applied in order to quantify clustering of the distribution of vortices. In many cases, clustering of the distribution persists after a long time if the initial condition is clustered. In the case of positive and negative vortices with the same absolute value of strength, the L function becomes positive for both types of vortices. Scattering or recoupling of pairs of vortices by a third vortex is remarkable.

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Transport properties of aqueous colloidal dispersions are controlled by the coagulation of particles in the dispersions. In order to study the coagulation kinetics and stability of colloid in a shear flow, which are practically important, trajectory analyses with electric double layer force have been used. So far, however, this analysis has not been applied to the heterocoagulation between oppositely charged particles in a shear flow. In the present study, the rate of shear coagulation of oppositely charged particle was calculated using the trajectory analysis. The calculated results indicate that the rate of heterocoagulation increases with decreasing ionic strength and increasing the magnitude of surface potential. The increase of the rate is considered to be due to the increases of the thickness of diffuse double layer and the magnitude of attractive double layer force.

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Two dimensional slow viscous flows past one or two circular cylinders are investigated by direct numerical simulation with incompressible Navier-Stokes equations. Steady uniform flows are obtained from the pressure difference imposed at the boundaries. In the simulation of one cylinder, drag coefficients are in good agreement with those obtained in experimental and other numerical studies for relatively low Re (1?Re?10²), and those in theoretical studies for very low Re (O(10^-2)?Re?1). In the case of two cylinders, we successfully visualize flow separation patterns which are similar to those in experimental and theoretical studies. We also investigate the flow separation patterns and drag coefficients of the cylinders in detail, and obtain the new flow separation pattern in some parameter space.

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We study the point vortex system in a two-dimensional bounded domain and the vortex filament system in a three-dimensional columnar region. We consider the system with the circulation condition that each point vortex (vortex filament) has a unique circulation subject to the distribution function. Then the mean field equation of point vortex system is obtained by three methods based on the different dynamical principles. Moreover, as an extension to the three-dimensional case, the mean field equation of nearly parallel vortex filament system is also obtained by applying one of them.

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In the paper a simple problem with two parameters for the backward heat equation is proposed. One parameter provides various situations: an initial and boundary value problem, a continuation problem and an initial value problem. Numerical results show that IPNS(Infinite-Precision Numerical Simulation) is superior in the stability rather than the simple discretization method. Numerical results by IPNS suggest existence and non-existence of the solution.

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A flow around plankton was investigated by a micro PIV measurement to quantify its swimming thrust in this study. The plankton is a larva of an Artemia Salina moving by flapping motion of a pair of arms. The maximum force for a forward movement arose in the power stroke phase, being obtained to be 1.1 × 10^-7 N by motion analysis taking account of the added virtual mass. The friction force obtained by integration of shear stress on the body surface was 3.4 × 10^-7 N. Thus, the thrust force was found to be 4.5 × 10^-7 N. The converting efficiency of the thrust to the force for a forward movement was found to be 24 %.

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Taconis oscillations in a closed long tube are studied by numerical calculations of the 2D compressible Navier-Stokes equations. Both end walls of the tube are hot (T = T_H ), and the central regions of side walls are cold (T = T_C ). The spontaneous oscillations in the tube are observed when temperature ratio θ = TH /TC ≥ 7.1. On the other hand, we do not obtain any oscillation in the tube at the temperature ratio θ < 5.7. When 5.7 < θ < 7.1, we find the two steady states (oscillation state and quiescent state) which are obtained from the different initial states.

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Spatial direct numerical simulations are performed to study the development of turbulent structures and the associated sound emission in a compressible boundary layer, in order to compare with corresponding high-speed train model experiments conducted in a moving model facility, where the free stream velocity is 500km/h (corresponding Mach number is 0.41). In the simulation, finite difference upwind-biased compact schemes¹⁾ (spectral-like resolution) are employed. Boundary conditions based on characteristic analysis for the Navier-Stokes equations are used so that acoustic waves are not reflected back into the domain. Disturbances of compressible isotropic turbulence are superimposed on the laminar profile at the inlet boundary layer in the computational box. The Reynolds number based on the displacement thickness at the inlet is 1640, which corresponds the measurement of the boundary layer undergoing transition. Simulation results present the complex development of the hairpin vortices leading to turbulent boundary layer structures and the associated sound generation. The numerical aerodynamic noise frequency range and the attenuation of sound are in good agreement with the experimental results.

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To study effects of deformation radius on stability of flow, we perform a linear stability analysis of a parallel shear flow whose velocity profile has a single maximum in the context of the Charney--Hasegawa--Mima equation. The linear stability analysis shows that as the deformation radius decreases, both the wavenumber and growth rate of the fastest growing mode decrease. To understand these results physically, first, the concept of resonance between neutral waves is applied. The analysis based on this concept well predicts the wavenumber of the fastest growing mode. Next, we introduce a low-degree-of-freedom system which represents a qualitative picture of the linear stability of the parallel shear flow. Combining this system with the concept of wave resonance, we derive a theoretical prediction of the growth rate of the fastest growing mode as a function of deformation radius. This prediction is in good agreement with the growth rate of the fastest growing mode calculated by the linear stability analysis.

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Effects of obliquity and period of planetary rotation on superrotation are examined using a Venus-like GCM. The cloud-top superrotational wind becomes larger with decreasing the oblique angle (< 60° under the conditions of the planetary rotation periods of 16 and 1 Earth days and < 30° under the condition of 243 Earth days). In the Venus-like simulations (243-day planetary rotation), the sensitivities of the atmospheric circulation to the obliquity are classified into three regimes of the slightly, intermediate, and highly oblique angles. The superrotation increases with the magnitudes of the meridional circulation and equator-pole air temperature difference for the slightly oblique angles, while it does not largely change for the highly oblique angles. In the intermediate oblique angle regime, the superrotation largely increases from 40 to 110 m s^-1 with increasing the equator-pole air temperature difference.

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We investigated the possibility of multiple equilibrium states in the atmospheric general circulation of Venus using Venus-like AGCM. We ran the model from two initial conditions. For a zero zonal wind initial condition, super-rotation is not reproduced and slow rotation appears. In a case with large zonal wind, increasing linearly with height initial condition, quasi-steady super-rotation with about 90 ms^-1 zonal wind is reproduced. However, this state suddenly collapsed and settled to slow rotation, which suggests the existence of a footprint of the equilibrium state with super-rotation in addition to the slow-rotation state in the solution space, along with the possibility of multiple equilibrium states. Results show that the wave with wavenumber one controls this collapse of super-rotation.

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With the aid of molecular dynamics, osmotic equilibrium between ideal solution and pure solvent separated by semi-permeable membranes is investigated numerically.The method using phantom molecules is developed to model the membranes reflecting solute molecules.The validity of van't Hoff law for the osmotic pressure is confirmed over a range of concentration up to 0.1 in mole fraction.

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An electrostatic model for osmotic flow through channels with surface charges is developed to understand the contribution of electrical charges to the transport of solution through narrow channels. The interaction energy between surface charges of the solute and the channel wall is used to express the osmotic reflection coefficient as a function of the surface charges, the ion concentration of the fluid, and the size ratio of the solute to the channel. Our model predicts that even for small Debye length compared to the channel size, the surface charges could significantly increase the osmotic flow, when the charges of the solute and the channel wall have the same sign.

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The luminal surface of capillary walls is covered by a layer of macromolecules referred to as the glycocalyx. In order to examine the role of the glycocalyx in the microvessel permeability, we have estimated the transport property of the microvessel wall, by using a one-dimensional model for the solute exchange through a serial pathway of the glycocalyx and the interendothelial cleft. The model provided reasonable predictions for the diffusional permeability and the reflection coefficient for solutes up to the size of albumin. The results suggest that the endothelial surface glycocalyx could form the primary molecular sieve in transcapillary pathways.

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Spatial derivative of the distribution function follows the lattice Boltzmann equation (LBE), because the advection term in the kinetic equation is linear in the lattice Boltzmann method. The cubic interpolated propagation (CIP) method and the finite difference method (FDM) are employed to discretize the kinetic equation for spatial derivative. We comparatively verify the approximation accuracy of the CIP and of the FDM with simulations of the Taylor vortex flow, of the Poiseuille flow, and of the unsteady Couette flow. The simulation result of the Taylor vortex flow reveals that the FDM indicates the 2nd-order accurate spatial convergence rate, and the applicability of the CIP method to the LBE is not good enough. The numerical simulations show that the differentiation of fluid density and of velocity is able to be calculated by a simple arithmetic calculation of the spatial derivative of the distribution function.

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This paper focuses on the Krom et al. hydrogen diffusion model in materials. Using the Sofronis and McMeeking model, we reconstruct our own finite element scheme based on the Krom et al. scheme, and apply the Galerkin method in this first trial. Results obtained with our new scheme are compared with previous results obtained by Sofronis and McMeeking, and Krom et al. to show good agreement.

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In order to understand the performance of the dielectric barrier discharge plasma actuator (DBD PA), analytical solutions of the electrostatic field by DBD PA were derived using the Laplace equation and the electric image method. Various electrodes shapes can be composed by the solutions. Main results are: 1) Electric field by a line electrode was composed using the solutions for the point electrodes. 2) Under a certain parameter condition, streamwise component of the electric fields seemed to be related qualitatively to the behavior of the streamwise jet velocity experimentally observed. 3) The relative permittivity of dielectric layer was supposed to have appreciable influence on the induced jet velocity suggesting that, under elevated temperatures, the jet induced by DBD PA may behave differently from that at room temperature.

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The importance of accurate and fast interpolation algorithm is growing up for helicopter simulation with multi-body configuration, because of complex movement of helicopter including rotor-rotation and flight motion. In this paper, interpolation algorithms are implemented for two different grids, Cartesian grid and curvilinear grid, of which the overlapped grid system consists. New searching algorithms are proposed to make full use of (1) the characteristics of Cartesian grid, (2) special geometric configuration of helicopter, and (3) load balancing in parallel computation. By applying these searching algorithms, efficient massive computation can be achieved for the helicopter configuration.

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The limitations of the finite element method (FEM) mainly on numerical dispersion errors and on model dimension indicate that an alternative deterministic approach is necessary for the coupled vibro-acoustic analysis in the higher frequency range. Therefore, a novel approach called the wave base method (WBM) is discussed since it requires no meshes, and subsequently provides no dispersion errors and small model dimension. A 2-dimensional WBM code is then developed, and some examples are solved to show some advantageous features of the WBM. Moreover, a simple vibro-acoustic simulation on spacecraft is demonstrated, and local responses can be obtained due to its deterministic characteristic. It is also shown that the WBM has high potential for the vibro-acoustic analysis with the wide frequency range.

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DSMC analysis was conducted for the flow around a reentry body at a high altitude about 80km. Gas particles were described by the VSS (Variable Soft Sphere) model, and three energy modes, namely translational, rotational, and vibrational energy modes were taken into account. Assuming pure nitrogen gas, five chemical species model and four chemical reactions model were applied. The NTC model suggested by Bird was used for particle collisions. For vibrational relaxation, Millikan-White's empirical formula was used with Park's high-temperature correction. Calculation was made for the reentry conditions of OREX (Orbital Reentry Experiment) and AOTV (Aeroassisted Orbital Transfer Vehicle) with the Mach number of 25 to 40, and compared with the extended merged shock-layer analysis only along a stagnation streamline. The results clarified the nonequilibrium properties of the flows.

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Mshless method is an effective tool for solving partial differential equations. In this method, CPU-time is wasted mainly in calculating shape functions. The modified radial point interpolation method (RPIM) has been proposed for yielding fast computation. In the radial point interpolation based methods, the shape functions can be evaluated by solving the linear systems and the key of the fast computation is to create the matrices of the linear systems in advance of the shape function evaluations. The purpose of this study is to solve three-dimensional Poisson problems using the modified RPIM, which requires less CPU-time than the RPIM.

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We propose a sophisticated method to numerically compute the partial differential equations (PDEs) of Black-Scholes type as they are. The method overcomes the difficulty of infinite domains and unbounded values of the solution. As an application we deal with the PDE with the effect of transaction costs.

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In the drying process of polymer solution droplets on substrates, some coupling effects of several phenomena such as contact line receding, surface skin formation by viscosity change, gelation of contact line (self-pinning) and outward flow in a droplet, are important. For a droplet having large contact angle, the lubrication approximation for thin films cannot be applied. Here, we have made the finite element simulation for a drying polymer solution droplet having 90 degree contact angle on a substrate using ALE (Arbitrary-Lagrangian-Eulerian) moving boundary method with experimentally measured rheological and transformation properties of polystyrene/anisole polymer solution and solved the contact line receding, outward flow by surface tension, solute distribution, and the buckling of a surface skin, which reproduces the experimentally observed results.

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In this study, numerical calculations of sound propagation for a simply modeled rocket plume duct with different jet configurations of H-IIA202 and 204 rockets have been conducted. The Euler flow calculation option of a hybrid Euler/LEE (Linearized Euler Equation) code is used. The results of these calculations indicate that the sound waves from the modeled rocket plume duct have different frequency characteristics according to the jet configurations.

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We propose a Combined Compact Difference (CCD) scheme for the grid system in which the boundary is located between regular grid points. We analyze the stability of the proposed CCD scheme for a 1-D advection diffusion problem by using the matrix method. The finite difference representation of the 1-D equation consists of the CCD scheme for the spatial derivatives and the 4th Runge-Kutta method for the time marching. It is shown that the new numerical method is stable for larger Courant number and diffusion number than those of the original method. We also show a numerical test of a 1-D advection diffusion simulation using this numerical method.

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This paper discusses on the resolution and the quality of the structural topology optimization using the level set method. Especially, it focuses on the effect of the reinitialization of the level set function on the final optimized topology. We propose Refined Mesh Reinitialization Method, and the optimal solution by three reinitialization methods are illustrated. Finally it is shown that the proposed refined mesh method gives a comparable or better resolution and quality of the final structural topology.

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