Although methods about building fish-like robots have attracted much research in recent years, new techniques are still required for developing superior robot fish. This paper presents a novel robot fish propelled by an active compliant propulsion mechanism. The key innovation is the combination of an active wire-driven mechanism with a soft compliant tail to accomplish subcarangiform swimming ...

We establish the existence and stability of multidimensional transonic flows with transonic shocks through an infinite nozzle of arbitrary cross-sections, including a slowly varying de Lavel nozzle. The transonic flow is governed by the inviscid steady potential flow equation with supersonic upstream flow at the entrance, uniform subsonic downstream flow at the infinite exit, and the slip bound...

A three-Dimensional computational model is used to simulate flow in a non-axisymmetric, convergent-divergent nozzle incorporating porous cavities for shockboundary layer interaction control. The nozzle has an expansion ratio (exit area/throat area) of 1.797 and a design nozzle pressure ratio of 8.78. Flow fields for the baseline nozzle (no porosity) and for the nozzle with porous surfaces of 10...

Fish produce context-specific sounds during social communication, but it is not known how acoustic behaviors have evolved in relation to specializations of the auditory system. Butterflyfishes (family Chaetodontidae) have a well-defined phylogeny and produce pulsed communication sounds during social interactions on coral reefs. Recent work indicates that two sound production mechanisms exist in...

PREFACE The Asian race has a high prevalence of congenital entropion. It was reported that over 20% of Japanese children have congenital entropion at the age of 1 year. One of the structural causes of this condition is the development of epiblepharon, which attaches the lower eyelid to the upper eyelid, and is also common among Asians. However, designing a procedure for modifying an epicanthus ...

Fuel after inflaming burns at high (till 15-20 МПа and more) pressure, thus is formed gaseous combustion products with temperature 3000-4500 K, which effuse to the ambient space through the nozzle. On length of the nozzle the temperature and pressure of them decrease, and the velocity increases, passing through a sound velocity in minimum (critical) cross-section of the nozzle and reaching 2700...

In nature, the caudal fins of fish species are frequently lost to some extent by aggressive behaviour, predation and diseases. To test whether the swimming performance of fish with different swimming capacities would be differentially affected due to caudal fin loss and regeneration, we investigated the critical swimming speed (Ucrit), swimming metabolic rate (M(O2)), tail beat frequency (f(TB)...

The compressible jet plume emerging from a planar convergent–divergent nozzle containing a separation shock is investigated experimentally and numerically. The investigation encompasses exit-to-throat area ratios (Ae=At) from 1.0 to 1.8 and nozzle pressure ratios from 1.2 to 1.8. Experiments were conducted in a variable-geometry nozzle facility, and computations solved the Reynolds-averaged Nav...

A theoretical study analyzing three-dimensional combustion acoustic instabilities in a liquid propellant rocket engine combustor has been conducted. A linear theory based on Crocco’s pressure sensitive time lag model is used. To apply this theory the combustor is divided into two main components, including the combustion chamber and the converging part of the nozzle. The assumption of concentra...