An aerodynamic ROM of the blade subjected to wake based on Fourier method for flow

Abstract

Summary A reduced‐order model (ROM) is presented based on Fourier method for flow to predict aerodynamic forces of blades subjected to periodic time‐varying upstream wakes. In the method, a time‐varying wake is decomposed into harmonic waves by fast Fourier transformation. Using the Fourier method for flow and neglecting the cross‐coupling between harmonics, the aerodynamic forces caused by the wake are represented by a linear combination of harmonics with the same frequencies as the wake. The coefficients of the aerodynamic force harmonics are interpolated at the per‐fitted curves of the normalized Fourier coefficients (coefficients of aerodynamic forces harmonics corresponding to a unit simple harmonic excitation)–frequency relationship. A blade example is used to show the ability of the proposed method. The results indicate that the ROM method can predict the aerodynamic forces of blades caused by wakes efficiently and accurately. The amplitude levels of wakes have a linear impact on the accuracy of the ROM. Neglecting the higher‐order cross‐coupling between the harmonics in the ROM method is acceptable.

Modeling of a turbine bladerow with stagger angle variation using the multi-fidelity influence superposition method

“…Their observation suggested that the multi-passage calculation is required in the investigation of manufacturing variations. In addition, distortions from intake geometry [10,11] and upstream wake [7,12,13] would also interact with the varied blade to create extra complications.…”