Control of ornithopters is challenging due to the unsteady flow generated by the flapping wings. The research presented in this paper is aimed at developing a sensor-based control methodology. Specifically, a distributed pressure sensing system embedded in the flapping wing surfaces is utilized to provide real-time aerodynamic force estimates to facilitate the development of feedback for an orn...

This paper deals with the boundary control problem of a nonhomogeneous flexible wing evolving under unsteady aerodynamic loads. The wing is actuated at its tip by flaps and is modeled by a distributed parameter system consisting in two coupled partial differential equations. Based on the proposed boundary control law, the well-posedness of the underlying Cauchy problem is first investigated by ...

In this paper, we investigate the aerodynamic aspects of formation flights. We do so by simulating the flow over flapping wings flying in grouping arrangement and in proximity of each others using the unsteady vortex lattice method. The results show that flying in V-shaped line formation at optimal spacing enables significant increase in the lift and thrust and savings in the power consumption....

The paper describes a formulation for aeroelastic analysis of aircraft with high-aspect-ratio wings. The analysis is a combination of a geometrically-exact mixed formulation for dynamics of moving beams and finite-state unsteady aerodynamics with the ability to model dynamic stall. The analysis also takes into account gravitational forces, propulsive forces and rigidbody dynamics. The code has ...

A high-order (up to 6th order) Navier-Stokes solver is coupled with a structural solver that decomposes the equations of three-dimensional elasticity into cross-sectional, smalldeformation and spanwise, large-deformation analyses for slender wings. The resulting high-fidelity aeroelastic solver is applied to the investigation of both a rigid and moderately flexible rectangular wing undergoing a...

All animals flap their wings in powered flight to provide both lift and thrust, yet few human-engineered designs do so. When combined with flexible wing surfaces, the resulting unsteady fluid flows and interactions in flapping flight can be complex to describe, understand, and model. Here, a simple modified actuator disk is used in a quasi-steady description of the net aerodynamic lift forces o...

This paper addresses the boundary control for flutter suppression of a flexible wing, both in bending and twisting displacements, under unsteady aerodynamic loads. The wing is modeled by a distributed parameter system described as two coupled partial differential equations. The problem is tackled in the framework of semigroup theory, and a Lyapunov-based stability analysis is carried out to ass...

The objective of this paper is to study the effect of an unsteady moving heat source on the aerodynamic performance of an NACA 0012 airfoil section, with particular focus on the lift and drag coefficients. The compressible Navier–Stokes equations are solved using a finite volume method as well as Spalart-Allmaras Model for turbulence simulation. The heat source periodically moves over the lower...

Recent results are presented from the application of a grid-free vortex method to the prediction of turbulent aerodynamic flows produced by road vehicles. The approach has the character of a large eddy simulation and incorporates a fast technique for evaluating the mutual interactions of several million vortex elements needed in describing the dynamically significant structure of the turbulent ...