Publication

Wake flow analysis for a hydrofoil with and without hydroelastic lock-in

François Avellan, Philippe Dupont
1987
Conference Papers

Abstract

The influence of the cavitation level on the vortex shedding frequency is used to compare the flow field in the wake of a blunt hydrofoil, with and without hydroelastic lock-in, and with a constant Reynolds number. Accurate LOA measurements allow us to examine in detail the base flow regime considered as the excitation source of the hydroelastic phenomena. Thanks to these measurements, a second vortex street superposed on the Karman street has been observed. Comparisons between measurements and calculations show that a Strouhal number evaluation based on boundary layer displacement thickness agrees well with experiments. Finally, the influence on the configuration of the wake is considered by modifying the shape of the trailing edge.

Official source

https://infoscience.epfl.ch/entities/publication/ed70a477-9d94-4286-9017-e4607d5b3658

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François Avellan, Philippe Dupont
1987
Conference Papers

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/ed70a477-9d94-4286-9017-e4607d5b3658

About this result

Related concepts (22)

Strouhal number

In dimensional analysis, the Strouhal number (St, or sometimes Sr to avoid the conflict with the Stanton number) is a dimensionless number describing oscillating flow mechanisms. The parameter is named after Vincenc Strouhal, a Czech physicist who experimented in 1878 with wires experiencing vortex shedding and singing in the wind. The Strouhal number is an integral part of the fundamentals of fluid mechanics.

Potential flow

In fluid dynamics, potential flow (or ideal flow) describes the velocity field as the gradient of a scalar function: the velocity potential. As a result, a potential flow is characterized by an irrotational velocity field, which is a valid approximation for several applications. The irrotationality of a potential flow is due to the curl of the gradient of a scalar always being equal to zero. In the case of an incompressible flow the velocity potential satisfies Laplace's equation, and potential theory is applicable.

Reynolds number

In fluid mechanics, the Reynolds number (Re) is a dimensionless quantity that helps predict fluid flow patterns in different situations by measuring the ratio between inertial and viscous forces. At low Reynolds numbers, flows tend to be dominated by laminar (sheet-like) flow, while at high Reynolds numbers, flows tend to be turbulent. The turbulence results from differences in the fluid's speed and direction, which may sometimes intersect or even move counter to the overall direction of the flow (eddy currents).

Related publications (2)

Wake flow analysis for a hydrofoil with and without hydroelastic lock-in

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