Macrocystis blades develop longitudinal corrugations in regions with strong current and wave action. This study examined the effect of corrugations on blade motion and blade drag by constructing flexible blades with different corrugation amplitude and a control blade with no corrugation. The models were designed to be dynamically and geometrically similar to natural blades. Acrylic molds were e...

The boundary layers of rainbow trout, Oncorhynchus mykiss, swimming at 1.02±0.09 L s(-1) (mean±s.d., N=4), were measured by the particle image velocimetry (PIV) technique at a Reynolds number of 4×10(5). The boundary layer profile showed unsteadiness, oscillating above and beneath the classical logarithmic law of the wall with body motion. Across the entire surface regions that were measured, l...

Drag reduction of an object is the major concern in many engineering applications. Experimental studies have been carried out on circular cylinder with helical grooves in a subsonic wind tunnel. Different cases of helical grooves with different pitches, helical groove angles and number of starts of helical groove on circular cylinder are tested. Experimental results show the drag coefficient is...

Many existing phenomena in nature are considered new design ideas in various fields of industry. Bionics is the application of biological methods and systems found in nature to the study and design of engineering systems and modern technology. By performing bionic review, the researchers found the penguins by delivering air locked under their wings and creating air bubbles, the drag significant...

Abstract In this work, bio-mimicking fish scale textures are produced by LPBF and AlSi7Mg0.6 powder to reduce drag forces on nautical components. For purpose, a surface texture inspired the European bass skin was modelled parametrized. Textures were applied over external of purpose-designed specimens. Additive manufacturing quality assessed using focus variation microscopy examine roughness as ...

SUMMARY A systematic sex-188 of twin-jet afterbodaes all terminating at the jet-exit has been tested at Mach numbers from M = 0.7 to 1.3 on a strut-mounted rig employing high pressure air for the Jet streams. The afterbody drag was derived from balance measurements of thrust-minus-drag and wind-off calibrations of thrust, and interpreted with the help of pressure plotting data. Two single-nozzl...