We study the role of unsteady lift in the context of flapping wing bird flight. Both aerodynamicists and biologists have attempted to address this subject, yet it seems that the contribution of unsteady lift still holds many open questions. The current study deals with the estimation of unsteady aerodynamic forces on a freely flying bird through analysis of wingbeat kinematics and near wake flo...

Potential flow solvers for 3D aerodynamic flows are commonly used in industrial applications. Two main difficulties preventing the even more widespread use of these codes are the limitations on the number of discretization elements and the user expertise and effort required to specify the wake location. In the paper we present an automatic wake generation strategy for a potential flow solver, a...

A computational method for flutter simulation of turbomachinery cascades is presented. The flow through multiple blade passages is calculated using a time-domain approach with coupled aerodynamic and structural models. The unsteady Euler/Navier-Stokes equations are solved in 2D using a second-order implicit scheme with dual time-stepping and a multigrid method. A structural model for the blades...

The steady and unsteady aerodynamic behaviour of a sailing yacht is investigated in this work by using full-scale testing on a Stewart 34. The aerodynamic forces developed by the yacht in real time are derived from knowledge of the differential pressures across the sails and the sail shape. Experimental results are compared with numerical computation and good agreement was found.

Most biological flyers undergo orderly deformation in flight, and the deformations of wings lead to complex fluid-structure interactions. In this paper, an aerodynamic-structural coupling method of flapping wing is developed based on ANSYS to simulate the flapping of flexible wing. Firstly, a three-dimensional model of the cicada’s wing is established. Then, numerical simulation method of unste...

The complex and unsteady aerodynamics of vertical axis wind turbines (VAWTs) pose significant challenges for simulation tools. Recently, significant research efforts have focused on the development of new methods for analysing and optimising the aerodynamic performance of VAWTs. This paper presents an electric circuit model for Darrieus-type vertical axis wind turbine (DT-VAWT) rotors. The nove...

This paper investigates the problem of active flutter suppression for a two-dimensional three degrees of freedom (3DOF) airfoil. With the influence of unsteady aerodynamic forces and parametric uncertainties, the output suboptimal control law design for a 3DOF airfoil control system is transformed into a constrained optimization problem. Then, the flutter robust suppression control law could be...

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 ...

A reduced-order model (ROM) is developed for aeroelastic analysis using the CFL3D version 6.0 computational uid dynamics (CFD) code, recently developed at the NASA Langley Research Center. This latest version of the ow solver includes a deforming mesh capability, a modal structural de nition for nonlinear aeroelastic analyses, and a parallelization capability that provides a signi cant increase...