This paper describes the fabrication of arrays of nanostructures (rings, crescents, counterfacing split rings, cylinders, coaxial cylinders, and other structures) by a four-step process: (i) molding an array of epoxy posts by soft lithography, (ii) depositing thin films on the posts, (iii) embedding the posts in epoxy, and (iv) sectioning in a plane parallel to the plane defined by the array of...

We analyze the global transport properties of turbulent Taylor-Couette flow in the strongly turbulent regime for independently rotating outer and inner cylinders, reaching Reynolds numbers of the inner and outer cylinders of Re(i) = 2×10(6) and Re(o) = ±1.4×10(6), respectively. For all Re(i), Re(o), the dimensionless torque G scales as a function of the Taylor number Ta (which is proportional t...

In the present paper problem of vortex images in annular domain between two coaxial cylinders is solved by q-elementary functions. We show that all images are determined completely as poles of q-logarithmic function, where dimensionless parameter q = r 2/r 2 1 is determined by square ratio of the cylinder radiuses. The resulting solution for the complex potential is represented in terms of the ...

Abstract We review the development of contra-rotating propellers from origins to present. Initially, these systems were proposed increase speed, then propulsive efficiency, and thus reduce fuel burn. Ultimately, they hit another environmental limit: too much noise. Acoustics has been in fact main focus past 30 years. Pioneering work done across countries demonstrated several unique features thi...

Computing the flow induced sound in rotating systems such as in ventilators and compressors yields additional challenges compared to setups without moving parts. In our contribution we apply a newly developed, hybrid computational scheme to a two-dimensional geometry, consisting of two infinitely long cylinders rotating around a common axis in a quiescent medium. The dominant sound producing ph...

A stationary plasma thruster (SPT, or Hall Thruster) is an electromagnetic thruster whose properties make it especially suitable for applications such as satellite station-keeping. Fig. 1 represents schematically the geometry of the SPT. Xenon is injected from the anode (rate on the order of 5mg/s), at the end of the dielectric cylinders and on the cathode side, outside the cylinders. We are ma...