Estimation of unsteady aerodynamic forces using pointwise velocity data

• Published in: Journal of fluid mechanics Vol. 804
• Main Authors: Gómez, F., Sharma, A. S., Blackburn, H. M.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 10.10.2016
• Subjects: Aerodynamic forces; Aerodynamics; Aerospace engineering; Coefficients; Computation; Computational fluid dynamics; Computer simulation; Cylinders; Decomposition; Direct numerical simulation; Drag; Drag coefficients; Flow structures; Fluid flow; Fluid mechanics; Fluids; Forces (mechanics); Fourier transforms; Low Reynolds number; Mathematical models; Measurement; Mechanics; Methodology; Modes; Navier-Stokes equations; Numerical prediction; Pressure distribution; Rapids; Reduced order models; Reynolds number; Simulation; Stress concentration; Unsteady; Unsteady aerodynamics; Unsteady flow; Velocity; aerodynamics; nonlinear dynamical systems; low-dimensional models
• ISSN: 0022-1120; 1469-7645
• DOI: 10.1017/jfm.2016.546

A novel method to estimate unsteady aerodynamic force coefficients from pointwise velocity measurements is presented. As opposed to other existing methodologies, time-resolved full velocity fields are not required. The methodology is based on a resolvent-based reduced-order model which requires the mean flow to obtain physical flow structures and pointwise measurement to calibrate their amplitudes. A computationally affordable time-stepping methodology to obtain resolvent modes in non-trivial flow domains is introduced and compared with previous existing matrix-free and matrix-forming strategies. The technique is applied to the unsteady flow around an inclined square cylinder at low Reynolds number. The potential of the methodology is demonstrated through good agreement between the fluctuating pressure distribution on the cylinder and the temporal evolution of the unsteady lift and drag coefficients predicted by the model and those computed by direct numerical simulation.