Fish Skin as a Multifunctional Hydrodynamic Material
Abstract
[Approved for public release]The interface between the fluid environment and the surface of the body in swimming fishes is criticalfor both physiological and hydrodynamic function. The skin surface in most species of fishes is covered with bony scales or toothlike denticles (in sharks). Despite the apparent importance of fish surfaces for understanding aquatic locomotion and near-surface boundary layer flows, relatively little attention has been paid to either the nature of surface textures in fishes or possible hydrodynamic effects of variation in roughness around the body surface within an individual and among species. Fish surfaces are remarkably diverse and in many bony fishes scales can have an intricate surface texture with projections, ridges, and comblike extensions. Shark denticles (or scales) are toothlike and project out of the skin to form a complexly textured surface that interacts with free-stream flow. The purpose of this proposal is to gather preliminary data on (1) the three dimensional surface structure of fish skin surfaces, and (2) to conduct experimental measurements of hydrodynamic flow patterns over shark skin samples. These data have Navy relevance for understanding how water flows over textured fish-like surfaces to contribute to the design of next-generation underwater vehicles. Three-dimensional surface imaging will use surface profilometry and micro-CT scanning, while analyses of flow dynamics will use a custom-designed flow tank to image near-surface flow over skin samples with a high-speed video camera. The diversity of fish scale types and textures and the effect of these surfaces on boundary layer flows and fish locomotor energetics is a rich area for future investigation.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 24, 2023
- Source ID
- N000142312684
Entities
People
- George V. Lauder
Organizations
- Office of Naval Research
- President and Fellows of Harvard College
- United States Navy