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Published February 2014 | Published + Supplemental Material + Submitted
Journal Article Open

An algorithm to estimate unsteady and quasi-steady pressure fields from velocity field measurements


We describe and characterize a method for estimating the pressure field corresponding to velocity field measurements such as those obtained by using particle image velocimetry. The pressure gradient is estimated from a time series of velocity fields for unsteady calculations or from a single velocity field for quasi-steady calculations. The corresponding pressure field is determined based on median polling of several integration paths through the pressure gradient field in order to reduce the effect of measurement errors that accumulate along individual integration paths. Integration paths are restricted to the nodes of the measured velocity field, thereby eliminating the need for measurement interpolation during this step and significantly reducing the computational cost of the algorithm relative to previous approaches. The method is validated by using numerically simulated flow past a stationary, two-dimensional bluff body and a computational model of a three-dimensional, self-propelled anguilliform swimmer to study the effects of spatial and temporal resolution, domain size, signal-to-noise ratio and out-of-plane effects. Particle image velocimetry measurements of a freely swimming jellyfish medusa and a freely swimming lamprey are analyzed using the method to demonstrate the efficacy of the approach when applied to empirical data.

Additional Information

© 2014 Published by The Company of Biologists Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed. Received 19 June 2013; Accepted 26 September 2013. The authors gratefully acknowledge S. Kern and P. Koumoutsakos for providing the three-dimensional numerical simulation of the self-propelled swimmer, and X. Liu for providing access to the pressure gradient integration code used in Liu and Katz (Liu and Katz, 2006). This research was supported by Office of Naval Research awards N000140810918 and N000141010137 to J.O.D. Deposited in PMC for immediate release.

Attached Files

Published - J_Exp_Biol-2014-Dabiri-331-6.pdf

Submitted - 1303.6966.pdf

Supplemental Material - JEB092767.pdf


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August 19, 2023
October 26, 2023