We perform a statistical analysis of experimental fully developed turbulence longitudinal velocity data in the Fourier space. We address the controversial issue of statistical intermittency of spatial Fourier modes by acting on the finite spectral resolution. We derive a link between velocity structure functions and the flatness of Fourier modes thanks to cascade models. Similar statistical beh...

This study numerically investigates turbulent pipe flow driven by a pulsating pressure gradient. While studies of laminar and turbulent pulsatile pipe flow with a single mode of oscillating pressure gradient have been carried out extensively, there is scarce literature on pulsating pressure gradients with multiple temporal Fourier modes. In many real-life engineering applications, for example, ...

Abstract - Use of efficient signal processing tools (SPTs) to extract proper indices for fault detection in induction motors (IMs) is the essential part of any fault recognition procedure. The Part1 of the two parts paper focuses on Fourier-based techniques including fast Fourier transform and short time Fourier transform. In this paper, all utilized SPTs which have been employed for fault fete...

It has been a long open question whether the pseudospectral Fourier method without smoothing is stable for hyperbolic equations with variable coeecients that change signs. In this work we answer this question with a detailed stability analysis of prototype cases of the Fourier method. We show that due to weighted L 2-stability, the N-degree Fourier solution is algebraically stable in the sense ...

It has been a long open question whether the pseudospectral Fourier method without smoothing is stable for hyperbolic equations with variable coefficients that change signs. In this work we answer this question with a detailed stability analysis of prototype cases of the Fourier method. We show that due to weighted L2stability, the N -degree Fourier solution is algebraically stable in the sense...

The Fourier Transform-Raman and Fourier Transform-Infrared spectra of 5-bromo-2-nitropyridine have been recorded. The observed frequencies were assigned to various modes of vibrations on the basis of normal coordinate calculations, assuming CS point group symmetry. The potential energy distribution associated with normal modes is also reported here. The assignment of fundamental vibrations agre...

Ni ferrite crystalline material is synthesized using a sol-gel method at two different temperatures. The vibrational and stretching modes, crystalline phase, size distribution and morphology of the products are investigated via Raman back-scattering and Fourier transform infrared (FTIR) spectroscopy, XRD and FESEM, respectively. Vibrational modes of spinel ferrite are observed at Raman and FTIR...

A family of orthonormal mode sets arises when Hermite-Gauss modes propagate through lossless first-order optical systems. It is shown that the modes at the output of the system are eigenfunctions for the symmetric fractional Fourier transformation if and only if the system is described by an orthosymplectic ray transformation matrix. Essentially new orthonormal mode sets can be obtained by lett...