We design and test micro-watt energy-harvesters inspired by tree trunks swaying in the wind. A uniform flow vibrates a linear array of four cylinders affixed to piezoelectric energy transducers. Particular attention is paid to measuring the energy generated as a function of cylinder spacing, flow speed, and relative position of the cylinder within the array. Peak power is generated using cylind...

Experimental data are presented for large arrays of rotating, finite-height cylinders to study the dependence of the three-dimensional (3D) mean flows on the geometric and rotational configurations of the array. Two geometric configurations, each with two rotational configurations, were examined at a nominal Reynolds number of 600 and nominal tip-speed ratios of 0, 2, and 4. It was found that t...

In this paper, the flow of an Oldroyd-B fluid past an array of circular cylinders in a channel is simulated by a parallelized pressure-based Finite Volume Method (FVM) using fine unstructured meshes. The numerical method is using the Discrete Elastic Viscous Split Stress vorticity (DEVSS-omega) formulation and the SIMPLER iteration algorithm. The spacing parameter between cylinders is selected ...

An infinite row of periodically spaced, identical rigid circular cylinders is excited by an acoustic line source, which is parallel to the generators of the cylinders. A method for calculating the scattered field accurately and efficiently is presented. When the cylinders are sufficiently close together, Rayleigh–Bloch surface waves, which propagate energy to infinity along the array are excite...

We study theoretically the propagation of elastic waves in two-dimensional composite media composed of a square array of hollow steel cylinders embedded in water using the finite-difference time-domain method. These composite media constitute a class of acoustic band gap materials with narrow pass bands in their transmission stop bands. The frequency at which the pass band occurs is tunable by ...

We report hydrogen storage at an ordinary pressure due to a bottle-neck effect of an ultramicroporous crystal. Stored hydrogen was kept at an ordinary pressure below -110 °C. The amounts of stored hydrogen gas linearly correlated with the initial pressures. These phenomena suggested the ultramicroporous tunnels worked as a molecular gas cylinder.