Reduced Order Modeling of Unsteady Flows Without Static Correction Requirement

Abstract

A new reduced-order modeling approach is presented. This approach is based on fluid eigenmodes and without using the static correction. The vortex lattice method is used to analyze unsteady flows over two-dimensional airfoils and three-dimensional wings. Eigenanalysis and reduced-order modeling are performed using a conventional method with and without the static correction technique. In addition to the conventional method, eigenanalysis and reduced-order modeling are also performed using the new proposed method, that is, without static correction requirement. Numerical examples are presented to demonstrate the accuracy and computational efficiency of the proposed method. Based on the obtained results, it is shown that the accurate reduced-order models of unsteady flows can be constructed without using the static correction technique.

An efficient reduced-order modelling approach based on fluid eigenmodes and boundary element method

“…Pervious works (Esfahanian and Behbahani-Nejad, 2002;Behbahani-Nejad et al, 2005) have shown that the existence of zero eigenvalues in the eigensystem is the main reason for needing to apply a static correction technique. Hence, by constructing a reduced-order model based only on the wake eigenmodes, the body quasi-static eigenmodes can be removed.…”

“…By constructing a reduced-order model based only on the wake eigenmodes, the body quasi-static eigenmodes are removed and it is possible to obtain satisfactory results without the static correction technique. This concept has been recently applied by Behbahani-Nejad et al (2005) for unsteady flow computations based on the vortex lattice method.…”

Analysis of Water Hammer with Different Closing Valve Laws on Transient Flow of Hydrogen-Natural Gas Mixture

“…ROM gave lower computational cost and reduced time for computation. ROM was recently used in the analysis of unsteady flows [21]. Agaie and Amin [22] used the ROM technique to study the effect of water hammer on transportation of hydrogen-natural mixture.…”

A reduced order of complete aeroelastic model for limit cycle oscillations

“…17. As stated in [1], the zero (29), respectively) to a step change in angle of attack is shown in Fig. 18.…”

“…Γ is a vector containing vortex strengths. Behbahani-Nejad et al [1] investigation show the aerodynamics equation in the form of (13) has some zero eigenvalues which makes some problem in constructing the reduced order aerodynamics model. They modified this model and named it as the modified vortex lattice model.…”