A Caltech Library Service

Lift coefficient estimation for a rapidly pitching airfoil

An, Xuanhong and Williams, David R. and Eldredge, Jeff D. and Colonius, Tim (2021) Lift coefficient estimation for a rapidly pitching airfoil. Experiments in Fluids, 62 (1). Art. No. 11. ISSN 0723-4864.

[img] PDF - Submitted Version
See Usage Policy.


Use this Persistent URL to link to this item:


We develop a method for estimating the instantaneous lift coefficient on a rapidly pitching airfoil that uses a small number of pressure sensors and a measurement of the angle of attack. The approach assimilates four surface pressure measurements with a modified nonlinear state space model (Goman–Khrabrov model) through a Kalman filter. The error of lift coefficient estimates based only on a weighted-sum of the measured pressures are found to be noisy and biased, which leads to inaccurate estimates. The estimate is improved by including the predictive model in an conventional Kalman filter. The Goman–Khrabrov model is shown to be a linear parameter-varying system and can therefore be used in the Kalman filter without the need for linearization. Additional improvement is realized by modifying the algorithm to provide more accurate estimate of the lift coefficient. The improved Kalman filtering approach results in a bias-free lift coefficient estimate that is more precise than either the pressure-based estimate or the Goman–Khrabrov model on their own. The new method will enable performance enhancements in aerodynamic systems whose performance relies on lift.

Item Type:Article
Related URLs:
URLURL TypeDescription ReadCube access Paper
An, Xuanhong0000-0001-6950-2867
Eldredge, Jeff D.0000-0002-2672-706X
Colonius, Tim0000-0003-0326-3909
Additional Information:© 2021 Springer-Verlag GmbH Germany, part of Springer Nature. Received 30 April 2020; Revised 07 October 2020; Accepted 19 November 2020; Published 08 January 2021. The support for this work by the US Air Force Office of Scientific Research FA9550-18-1-0440 with program manager Gregg Abate is gratefully acknowledged. Supported under the US Air Force Office of Scientific Research FA9550-14-1-0328 with program manager Douglas Smith is also gratefully acknowledged. The first author would like to thank the supported under ONR MURI Grant N00014-14-1-0533 with program manager Robert Brizzolara. The insightful suggestions from Professor C. Rowley and S. Otto at Princeton University are sincerely appreciated. The authors declare that they have no conflict of interest.
Funding AgencyGrant Number
Air Force Office of Scientific Research (AFOSR)FA9550-18-1-0440
Air Force Office of Scientific Research (AFOSR)FA9550-14-1-0328
Office of Naval Research (ONR)N00014-14-1-0533
Issue or Number:1
Record Number:CaltechAUTHORS:20210121-111627081
Persistent URL:
Official Citation:An, X., Williams, D.R., Eldredge, J.D. et al. Lift coefficient estimation for a rapidly pitching airfoil. Exp Fluids 62, 11 (2021).
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:107633
Deposited By: Tony Diaz
Deposited On:21 Jan 2021 19:37
Last Modified:21 Jan 2021 19:37

Repository Staff Only: item control page