Experimental Visualization of the Near-Boundary Hydrodynamics About Fish-Like Swimming Bodies
Abstract
Experimental investigation into the near boundary flow about fish-like swimming bodies is performed up to Reynolds number 106 using laser Doppler velocimetry (LDV) and particle imaging techniques. The turbulence in the boundary layer of a waving mat and swimming robotic fish were investigated. The study of the MIT RoboTuna and a two-dimensional representation of the backbone of the robotic swimming fish was performed to further assess the implications of such motion on drag reduction. Particle Image Velocimetry (PIV) experiments with the MIT RoboTuna indicate a laminarisation of the near boundary flow for swimming cases compared with non-swimming cases along the robot body. LDV and PW experiments were performed. LDV results show the reduction of turbulence intensity, near the waving boundary, for increasing phase speed ratio Cp/U up to 1.2 m/s after which the intensities begin to increase again through Cp/U =2.0, where numerical simulations by Zhang (2000) showed separation reappearing on the back of the crests. Velocity profiles show an acceleration of the fluid beyond the inflow speed at the crest region increases with increased phase speed and no separation was present in the trough for the moving wall.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2001
- Accession Number
- ADA405879
Entities
People
- Alexandra H Techet
Organizations
- Massachusetts Institute of Technology