A direct numerical simulation (DNS) of compressible turbulent flow along a flat wall was performed in order to investigate the mechanical influence of a low Mach number turbulent boundary layer on a wall surface. By using a wall element model and instantaneous pressure distribution from the DNS result, we observed the characteristics of the wall vibration and compared that to the structures in the turbulent boundary layer. As a result, the spatial scale of the wall vibration was similar to that of the large scale structures (LSS) of pressure distribution in the flow field rather than the fine scale structures. Tendency of the mean displacement of a wall surface depends on the conditions of the wall element model and the turbulent boundary layer. We found that there was a condition at which the tendency changed obviously.

In order to investigate the modulation of turbulence structures in boundary layers on various rough walls, direct numerical simulations were performed by solving the fundamental equations with external forces by roughness on a wall. As a result, in the case that the height of the roughness is smaller than the border of the viscous sublayer and buffer layer, the turbulence structures similar to those on a smooth wall could be observed. In contrast, in the case that the height is larger than the buffer layer, the characteristics of turbulence structures drastically changed. We propose a new normalization method in which we can observe universally the spatial features of turbulence structures on a rough wall. This means that, by using the proposed method, the knowledge for wall turbulence obtained in past studies can be applied to the case of turbulent flow along a rough wall.

I used boundary condition and lattice placement proposed in the previous study and used the upwind difference scheme and the CIP method to solve constituent equation. I compare the calculation results with existing experimental results and examined calculation method and boundary condition. As a result applying the boundary condition proposed in the previous study to the CIP method, to solve the recirculation region generated from the corner was possible. The results of this study are thought to be useful for numerical analysis of viscoelastic fluid flow.

In this paper, I present results from nonlinear parabolized stability equations (NPSE) of a flat plate boundary layer transition. I used a Finite different method in the streamwise direction, a Fourier Galerkin method in the spanwise direction and time, and a Chebyshev Collocation method in the wall-normal direction. I compute K-type transition and H-type transition. In both the case, NPSE results are in good agreement with the spatial Direct Numerical Simulation (SDNS) results.

In our previous study, antimicrobial effect of ultra-fine bubble (UFB) mixtures for fresh vegetables was observed in an alternating flow. The Viable Bacterial Count (VBC) for UFB mixtures was less than those before treatment within the experimental errors. The effect on the VBC for UFB including hypochlorite was strongly expressed with alternative flows. Higher efficiency was thus suggested. However, effect of washing time was not discussed. In this situation, we investigated them, and the discussed optimum time on the washing effect for UFB mixtures.

A hammering method is most commonly used to detect defeats in concrete structures. Though this method is relatively simple, the detection results depend upon the subjective sense of the inspector. In this study, we use a hammering test using a rotary hammering device instead of a conventional test hammer to ensure detection of defeats. The impact sound is measured above each hammering point while the rotary device is driven. The measured sounds at the healthy parts and the defective parts are compared in the time and frequency domain. From the time wave forms and the frequency spectra of sound pressure, there is clear difference between the healthy parts and the defective parts under a suitable hammering condition.

In this study, the dynamic responses of a 4DOF non-linear vehicle model under the excitation of triangular road humps are investigated with numerical simulation. The model displays complicated dynamic responses including harmonic motions and chaos. It is concluded that the chaotic vibrations of the model can be induced by selection of the parameters of the humps.

I and my research partners are focusing on the decrease of acceleration of the ambulance's bed to make the journey of arriving at hospital more comfortable or not to worse the condition of patients either let CPAOA happen. We estimate the effect of acceleration's reduction by comparing the feedback dates with the input ones. And by putting our anti-vibration device on the artificial earthquake producing platform, we can imitate the scenes of device on the real roads. This year we've reformed the base of the equipment and we've confirmed that we've made a great improvement on the reduction of the acceleration converted from the floor to the bed, which was about 10% up compared to the last year's. .

This paper proposes a transmitted vibration reduction method for rotating machinery by double vibration isolation structure. Rotating machinery with unbalance mass generate large vibration during spin cycle. For vibration analysis in case of flexible foundation installation, a three degrees-of-freedom mass-spring-damper model is adopted to consider the foundation vibration characteristics. By analysis of transmitted vibration to the foundation and experiment, vibration reduction effect of the double vibration isolation structure is confirmed. The foundation vibration in spin cycle of rotating machinery is reduced by the double vibration isolation structure.

In this study, the effect of the lamination gap on the flexural modulus of the laminate, particularly the plain-weave fabric composite laminate with two plies, is investigated through finite element analyses. Through the numerical investigation, it is found that the maximum flexural modulus is obtained when there is no lamination gap and the minimum flexural modulus is obtained when there is a lamination gap of half wave length of the out-of-plane waviness of the woven yarns along one of the running directions of yarns.

In this study, a dynamic mode decomposition technique was developed with proper orthogonal decomposition and applied to the mode analysis of the generated sound of snare drum. In the experiment, simultaneous measurement of vibrational acceleration of the shell of the drum and far field sound pressure were performed. Experimental results show that 1^st to 3^rd mode of vibrational acceleration were dominant and 1st mode made the biggest far field sound. Further, it was shown that 1^st mode sound was caused by the resonance of the air fluid in the drum and the sound caused by the interference of the shell and the stick depended on the proficiency of the player.

In this study, we made the acoustic meta-materials for changing sound transmission property in semi-finite field. By arranging apparent density of the materials distributed over the aperture through which the wave penetrated perpendicularly, the sound transmission path could be inclined from the nominal axis of the wave front. At first, we devised several patterns of the acoustic meta-materials. The first pattern is formed as a series of slits. The second pattern is a two-dimensional array of square props. The third pattern is an array of three-layered slits. The wave propagation analysis in two-dimensional free field incorporating the material was performed using the finite element method. We found from the simulation that all of three types affected the sound deflection. We then conducted sound field measurements for the meta-materials. Consistent results have been obtained in experiments. It is also found that the directivity increases as the frequency becomes high. From these investigations, the acoustic meta-materials is thought to be effective for sound deflection control.

This paper describes a numerical solution to the shape optimization problems of viscous flow fields. The drag minimization problem and lift maximization problem for an isolated body in uniform flow were formulated in the domain of unsteady-state viscous flow fields. The shape gradient of the shape optimization problems were derived theoretically using the adjoint variable method, the Lagrange multiplier method and the formulae of the material derivative. Reshaping was accomplished using a traction method that was proposed as a solution to domain optimization problems. Numerical analyses program for the shape optimization is developed based on FreeFem++, and the validity of proposed method is confirmed by results of 2D numerical analyses.