Finite state induced flow models. I - Two-dimensional thin airfoil

Peters, David A.; Karunamoorthy, Swami; Cao, Wenming

doi:10.2514/3.46718

Cited by 310 publications

(176 citation statements)

References 5 publications

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“…In the authors' estimate, Goman and Khrabrov's model offers at least two advantages over the existing models (such as Theodorsen [12] or Peters et al [29]). First, the model is cast in the form of a single ordinary differential equation (ODE) and two algebraic equations, one each for lift and the quarter-chord pitching moment.…”

Section: F Fuselage Kinematicsmentioning

confidence: 99%

Dynamics and Performance of Tailless Micro Aerial Vehicle with Flexible Articulated Wings

et al. 2012

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The purpose of this paper is to analyze and discuss the performance and stability of a tailless micro aerial vehicle with flexible articulated wings. The dihedral angles can be varied symmetrically on both wings to control the aircraft speed independently of the angle of attack and flight-path angle, while an asymmetric dihedral setting can be used to control yaw in the absence of a vertical tail. A nonlinear aeroelastic model is derived, and it is used to study the steadystate performance and flight stability of the micro aerial vehicle. The concept of the effective dihedral is introduced, which allows for a unified treatment of rigid and flexible wing aircraft. It also identifies the amount of elasticity that is necessary to obtain tangible performance benefits over a rigid wing. The feasibility of using axial tension to stiffen the wing is discussed, and, at least in the context of a linear model, it is shown that adding axial tension is effective but undesirable. The turning performance of an micro aerial vehicle with flexible wings is compared to an otherwise identical micro aerial vehicle with rigid wings. The wing dihedral alone can be varied asymmetrically to perform rapid turns and regulate sideslip. The maximum attainable turn rate for a given elevator setting, however, does not increase unless antisymmetric wing twisting is employed.

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Section: F Fuselage Kinematicsmentioning

confidence: 99%

Dynamics and Performance of Tailless Micro Aerial Vehicle with Flexible Articulated Wings

et al. 2012

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“…Moreover, L and M denote the aerodynamic lift force and moment acting on the airfoil. Here, the classical finite-state induced flow theory by Peters et al 16 is used to approximate the unsteady aerodynamic loads of the inviscid, incompressible flow. The force and moment acting on the aerodynamic surface are given by…”

Section: Aeroelastic Response Of the Resonating Unitmentioning

confidence: 99%

Harnessing fluid-structure interactions to design self-regulating acoustic metamaterials

Casadei

Bertoldi

2014

Journal of Applied Physics

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The design of phononic crystals and acoustic metamaterials with tunable and adaptive wave properties remains one of the outstanding challenges for the development of next generation acoustic devices. We report on the numerical and experimental demonstration of a locally resonant acoustic metamaterial with dispersion characteristics which autonomously adapt in response to changes of an incident aerodynamic flow. The metamaterial consists of a slender beam featuring a periodic array or airfoil-shaped masses supported by a linear and torsional springs. The resonance characteristics of the airfoils lead to strong attenuation at frequencies defined by the properties of the airfoils and the speed on the incident fluid. The proposed concept expands the ability of existing acoustic bandgap materials to autonomously adapt their dispersion properties through fluid-structure interactions, and has the potential to dramatically impact a variety of applications, such as robotics, civil infrastructures, and defense systems.

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“…B v B , etc. ), K is the stiffness matrix, and Rq; _ q; represents generalized forces (including aerodynamic forces), which are a function of the finite state inflow [28,29] velocities, . Coupling of the rigid-body and flexible dynamics occurs through the dependency of M, C, and R. Typically, the B reference frame linear and angular velocities are represented by v B !…”

Section: A Summary Of Governing Differential Equationsmentioning

confidence: 99%

“…For simplicity, the initial strain initial and point moments M pt will be assumed to be zero. The finite strain formulation [28,29] for aerodynamic forces and moments is linear in the discrete trailing edge surface deflections. These assumptions and formulations, combined with a point force representing a simplistic engine model, allow the generalized force to be expressed as [30] …”

Section: Additional Matrices H Hb and H H _ _mentioning

confidence: 99%

Trajectory Control for Very Flexible Aircraft

Shearer

Cesnik

2008

Journal of Guidance, Control, and Dynamics

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This paper focuses on trajectory control of the six-degree-of-freedom body fixed reference frame located on a very flexible aircraft. The six-degree-of-freedom equations of motion of a reference point on the aircraft are coupled with a low-order strain-based nonlinear structural analysis and an unsteady finite state potential flow aerodynamics model. Because of the inherent flexibility of the aircraft, the low-order structural frequencies are of the same order as the rigid-body mode frequencies. This coupling is accounted for in the controller development. A heuristic approach based upon pilot behavior is developed. The approach separates the problem into two parts: a fast inner loop and a slower outer loop. Dominant kinematic nonlinearities are handled in the outer loop, whereas the inner loop is further separated into a lateral and longitudinal motion. Control of the inner-loop lateral motion is accomplished using a standard linear quadratic regulator. For the longitudinal motion, dynamic inversion is used. Differences between the desired and actual trajectories are handled using a nonlinear proportional, integral, derivative approach. The closed-loop time integration is accomplished using an implicit modified Newmark method. A capstone numerical simulation is presented, highlighting the strengths and weaknesses of the method.

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Finite state induced flow models. I - Two-dimensional thin airfoil

Cited by 310 publications

References 5 publications

Dynamics and Performance of Tailless Micro Aerial Vehicle with Flexible Articulated Wings

Dynamics and Performance of Tailless Micro Aerial Vehicle with Flexible Articulated Wings

Harnessing fluid-structure interactions to design self-regulating acoustic metamaterials

Trajectory Control for Very Flexible Aircraft

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