Newsletter  2015.2  Index

Theme : "The Conference of Fluid Engineering Division" Preface M.Oshima, D. Sakaguchi, Y. Takahashi Aeronautical Industry Overview and Brief Introduction of Fluid-related R&D Activities at JAXA Kazuhiro NAKAHASHI (Institute of Aeronautical Technology, Japan Aerospace Exploration Agency) 3D flow configuration of multiple circular impinging jets Yoshiyasu ICHIKAWA (Tokyo University of Science) Relationship between Flow characteristics and Shear-banding on step shear in wormlike micellar solutions Masatoshi ITO (Nagaoka University of Technology) Effect of a Sinusoidal Riblet on Advection of Vortices in Wall Turbulence Monami SASAMORI, Hiroya MAMORI, Kaoru IWAMOTO, Akira MURATA (Tokyo University of Agriculture and Technology) Highly temporal analysis of underwater streamers with a streak camera Hidemasa FUJITA (Tohoku University) Digital holographic particle measurement using deconvolution and its application Yuto ASAI (Graduate School of Kyoto Institute of Technology), Shigeru MURATA, Yohsuke TANAKA (Kyoto Institute of Technology) The Soap Bubbles Art Megumi Akashi (Hokkaido University) The Dream Aquarium Daichi SAITO, Tomonari Sato (Hokkaido University)

 

The Dream Aquarium

Daichi SAITO Hokkaido University Tomonari SATO Hokkaido University

Abstract

We participated JSME 13th Dreams of Flow Contest held at Toyama University as Team Dream Aquarium. In this report, we summary our articles and demonstrations.

Dream Aquarium is the name of our articles and demonstrations. It consists of four-link mechanisms (Fig. 1) and small scale models of aquatic animals shaped by ourselves (Fig. 2). With using these items, we can easily compare the magnitude of drug on aquatic animals. The model has shape for lower flow drag moves forward by blowing the uniform air flow for two models mounted on the four-link mechanisms.

Fig. 1  A photo of four-link mechanisms

Fig. 2  Pictures of aquatic animal models

Generally, the drag F acting on the object in steady, uniform flows is formulized

(1)

where ρ is the density of the fluid, U is the main stream velocity, S and C_D are the projected area and the drag coefficient of the object. As it is clear from Eq. (1), S makes not a few contributions to F. This means aquatic animals whose body size are large such as whale shark and dolphin are at a disadvantage when we standardize the scale of length of the models and compare the drug. This is not suitable for your articles, and thus we decided to standardize S of all models to remove the effect of the body size. Now ρ, U, and S are constant and F is in proportion to C_D. Therefore the comparison of F by four-link mechanisms becomes equivalent to the comparison of C_D of each model. It becomes not so easy and interesting to estimate the correct ranking of drug, just like a horse race. We named this competition “fish race.” 

Results of the fish race are summarized in the Table 1. We also visualized the flow fields around models by the method of smoke wire and took pictures (Fig. 3) to know what determines decision on the race.

Table 1  The result of “fish race”

Fig. 3  Visualization of flow field around models

Key words

aquatic animal, drug, visualization