In this work, the application of harmonic balance technique is demonstrated for transonic buffet cases. The method represents an alternative to time-marching simulations that are expensive complex flow Here applied on different test cases with inherently unsteady flows, i.e. two aerofoil configurations undergoing buffet. A gradient-based, variable time period used estimate frequency oscillation...

We propose a niche Genetic algorithm (GA) for the two-dimensional (2D) harmonic retrieval in the presence of correlative zero-mean, multiplicative, and additive noise. Firstly, we introduce a 2D fourth-order time-average moment spectrum which has extremum values at the harmonic frequencies. On this basis, the problem of harmonic retrieval is treated as a problem of finding the extremum values f...

This paper presents an improved method of estimating flux angle, rotor position, and velocity by tracking the position of spatial saliencies in an ac machine. Specifically, a machine model is presented which accurately models the behavior of ac machines with multiple spatial harmonic saliencies. The effects of multiple spatial harmonic saliencies on the estimation of flux angle, position, and v...

This paper describes a multi-pitch analysis method using specmurt analysis with iterative estimation of the quasioptimal common harmonic structure function. Specmurt analysis (Sagayama et al., 2004) is based upon the idea that superimposed harmonic structure pattern can be expressed as a convolution of two components, a fundamental frequency distribution and a ‘common harmonic structure’ functi...

The problem of estimating the power spectra of non-stationary stochastic processes by using the harmonic wavelet transform is addressed in this paper. Conventional spectral analysis provides spectral coefficients that are averaged over time and thus, does not represent the evolutionary behavior of power spectra of non-stationary processes. In this study, evolutionary power spectrum of a non-sta...