Mathematical Aeroelasticity: A Survey (original) (raw)

2015

A variety of models describing the interaction between flows and oscillating structures are discussed. The main aim is to analyze conditions under which structural instability (flutter) induced by a fluid flow can be suppressed or eliminated. The analysis provided focuses on effects brought about by: (i) different plate and fluid boundary conditions, (ii) various regimes for flow velocities: subsonic, transonic, or supersonic, (iii) different modeling of the structure which may or may not account for in-plane accelerations (full von Karman system), (iv) viscous effects, (v) an assortment of models related to piston-theoretic model reductions, and (iv) considerations of axial flows (in contrast to so called normal flows). The discussion below is based on conclusions reached via a combination of rigorous PDE analysis, numerical computations, and experimental trials.

Research on Aeroelasticity Phenomenon in Aeronautical Engineering

Aerodynamics [Working Title], 2020

Aeroelasticity phenomena arise when structural deformations induce changes on aerodynamic forces due to airplane structures that are not completely rigid. The additional aerodynamic forces cause an increase in the structural deformations, which leads to greater aerodynamic forces in a feedback process. These interactions may become smaller until reaching a condition of equilibrium or may diverge catastrophically if resonance occurs. Flutter is an instability aeroelasticity phenomenon which is the most difficult to predict. In this chapter, a numerical method and an experimental method were realized to predict aeroelastic response and characteristic parameters of a wing structure. The numerical method was firstly developed based on the interaction between computational fluid dynamic and computational structural dynamic methods using a coupling system, fluid–solid interaction (FSI), in the ANSYS software. Then, an experiment was set up in suitable conditions to study aeroelasticity ch...

An Analysis of the Aeroelastic Behaviour of a Typical Fan-Blade With Emphasis on the Flutter Mechanism

Volume 5: Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation; Education; General, 1996

Aeroelasticity phenomena are characterised by the interaction of fluid and structural domains, whose describing equations are nonlinear. Classical prediction methods are generally based on treating the two domains separately while integrated (or coupled) approaches link them via boundary conditions throughout the solution phase. In turbomachinery environments, the aeroelasticity problem is further compounded by the fact that blades vibrate with a relative phase with respect to each other, the value of which is not necessarily known. Using a 3D thin-layer Reynolds-averaged Navier-Stokes solver and a 3D structural model, various coupled and uncoupled flutter analysis methods are compared with particular emphasis on inter-blade phase angle. A typical fan geometry, the NASA Rotor 67 blade, was chosen as the test case since steady-flow measurements are available for this particular structure. Two flow conditions, near peak-efficiency and near stall, were investigated for inter-blade phas...

Evaluation of Reynolds number effects on flutter derivatives of a flat plate by means of a computational approach

Journal of Fluids and Structures, 2008

This paper proposes an efficient method to determine the flutter derivatives of two-dimensional streamlined cylinders by means of a modified indicial approach adapted to a Navier–Stokes solver using an Arbitrary Lagrangian Eulerian formulation. The method relies on heave or pitch motion imposed on the structure according to smoothed-ramp-time histories and on the computational evaluation of the transient forces that arise on the obstacle. Hence, the indicial transfer function that relates the structural motion to the induced force in the frequency domain is obtained. The approach is applied to a flat plate of finite thickness and length immersed in a viscous flow. The low computational costs of the method allow the effects of Reynolds number to be evaluated on both the aerodynamic and aeroelastic behaviour for a wide range of Re values. The flow around the motionless plate is compared to the well-known Blasius and Goldstein solutions. The flutter derivatives extracted from simulations with a moving plate are compared to ones obtained from the Theodorsen function in the frame of the thin airfoil theory. Relationships between the variation of Re, the fluid flow phenomena and the flutter derivatives are highlighted in order to identify the flow field features that affect the flutter derivatives to the greatest extent.

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