Inverse lift: a signature of the elasticity of complex fluids?

Abstract

To understand the mechanics of a complex fluid such as a foam we propose a model experiment (a bidimensional flow around an obstacle) for which an external sollicitation is applied, and a local response is measured, simultaneously. We observe that an asymmetric obstacle (cambered airfoil profile) experiences a downards lift, opposite to the lift usually known (in a different context) in aerodynamics. Correlations of velocity, deformations and pressure fields yield a clear explanation of this inverse lift, involving the elasticity of the foam. We argue that such an inverse lift is likely common to complex fluids with elasticity.

arXiv comment4 pages, 4 figures, revised version, submitted to PRL

References in corpus (2)

• Hysteresis and Avalanches in Two Dimensional Foam Rheology Simulations
• Two-dimensional flow of foam around an obstacle: force measurements

Cited by in corpus (5)

• Rate Dependence and Role of Disorder in Linearly Sheared Two-Dimensional Foams
• Two-dimensional flow of foam around a circular obstacle: local measurements of elasticity, plasticity and flow
• Local description of the two-dimensional flow of foam through a contraction
• Stokes experiment in a liquid foam
• Elasto-plastic flow of a foam around an obstacle