Large-Eddy Simulation of Bio-Inspired Geometries
Overview
Incompressible wall-resolved large eddy simulation of an undulated cylinder based on the harbor seal whisker, at Re = 2,400. The undulations disrupt the alternating vortex shedding pattern seen from straight cylinders. This leads to a reduction in RMS lift.
Flow Visualization
Iso-surfaces of the Q-criterion colored by spanwise vorticity ωz. The undulations break up the spanwise-coherent vortex tubes that drive periodic lift on a smooth cylinder.
Key Aspects
Geometry
Undulated cylinder parameterized after the harbor seal vibrissa.
LES Closure
OpenFOAM incompressible large eddy simulation with the WALE sub-grid-scale model for correct near-wall behavior.
Numerics
Second-order accurate in both space and time.
Biological Inspiration
Harbor seals track hydrodynamic wakes left by prey, sometimes long after the fish has passed. It is suspected that the seals' whiskers undergo minimal excitation in free flow.
Methodology
- Solver: Incompressible large eddy simulation in OpenFOAM.
- SGS model: WALE.
- Discretization: Second-order in space and time.
- Reynolds number: Re = 2,400, based on the mean cylinder thickness.
Reference
- "Harbor seal vibrissa morphology suppresses vortex-induced vibrations." Journal of Experimental Biology, vol. 213, no. 15, 2010.