Open Access

ARTICLE

Uncertainty Quantification of the Interaction of a Vortex Pair With the Ground

by

1 Instituto Superior Técnico, Tech. Univ. Lisbon, LASEF, Lisbon, Portugal.

Computer Modeling in Engineering & Sciences 2011, 73(1), 23-44. https://doi.org/10.3970/cmes.2011.073.023

Abstract

The evolution of a two-dimensional vortex pair in ground effect was studied under the influence of random initial inputs comprising vortex strength (circulation) or initial vortex position. The paper addresses the questions of how do variations and uncertainties of initial conditions translate to the variability of vortex pair evolution. The stochastic solutions were obtained recurring to the Polynomial Chaos Expansion method of random processes applied to the Navier-Stokes equations for a laminar flow. The method quantifies the extent, dependence and propagation of uncertainty through the model system and, in particular, a methodology for the calculation of the vortices trajectory variability, i.e. their confidence interval, could be obtained, provided that the random inputs are not sufficiently high to destroy the mean solutions coherence. The random initial vortex position or the vortex circulation with a variability coefficient of 10% promote after t* = 3, one vortex turnover, vortex trajectories that within a 90% confidence interval display an error bar with lengths up to 2r⁰ (two times the initial vortex radius).

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Keywords

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