Linear Frequency Domain Reduced Order Modelling of Aerofoil Gust Response

Abstract

A method for constructing reduced order models of an aerofoil subject to gusts is presented. The method is based on subspace system identification in the frequency domain in order to obtain a model which retains the dynamic information of the original system, while having a comparatively smaller dimension. The gust is prescribed through the domain using the split velocity method to obtain the system frequency response. This is used to find the state matrices of the reduced system. By prescribing a series of 1-cosine gusts, it is shown that the reduced system obtained agrees well with the original system.

Load Control for Unsteady Gusts with Control Surfaces using the Linear Frequency Domain

“…They demonstrated that a well functioning load alleviation system needs to have a control surface on the outer wing and one on the inner wing so that essential parts of the load distribution of the wing-span can be influenced by the control system. Bagheri, Jones and Gaitonde [5] developed a model to predict gust responses using a reduced model of the LFD solver and could show that, for a series of 1-cosine gusts, their model proved a good agreement with the original system. Comparisons between LFD results and Double Lattice Methods (DLM) for gust encounter simulations on the NASA Common Research Model (CRM) were done by Kaiser, Friedewald and Nitzsche [6] and showed good results in terms of time savings and accuracy for applications in the linear gust regions.…”