The present study explores flow visualization experiments with various blunt shaped bluff bodies placed inside a circular pipe. The bodies mainly comprise of modifications of trapezoidal cylinder, most widely used in practical applications, such as vortex flowmeters. The present configuration possesses the feature of both internal and external flows with low aspect ratio. The vortex dynamics of...

We employ numerical simulation to investigate the hydrodynamic performance of anguilliform locomotion and compare it with that of carangiform swimming as the Reynolds number (Re) and the tail-beat frequency (Strouhal number, St) are systematically varied. The virtual swimmer is a 3-D lamprey-like flexible body undulating with prescribed experimental kinematics of anguilliform type. Simulations ...

Mach wave radiation from supersonic jets is revisited to better quantify the extent to which linearized equations represent the details of the actual mechanism. To this end, we solve the linearized Navier–Stokes equations ~LNS! with precisely the same mean flow and inflow disturbances as a previous direct numerical simulation ~DNS! of a perfectly expanded turbulent M51.92 jet @Freund et al., AI...

Propulsion and maneuvering underwater by flapping foil motion, optimized through years of evolution, is ubiquitous in nature, yet marine propulsors inspired by examples of highly maneuverable marine life or aquatic birds are not widely implemented in engineering. Performance data from flapping foils, moving in a rolling and pitching motion, are presented at high Reynolds numbers, Re=Uc/nu, or O...

This paper presents first-principle and numerical studies of flapping flight with the objective of optimizing the force production and propulsive efficiency. Strouhal number is identified as a critical parameter affecting all of these variables, and the optimum ranges of Strouhal number are calculated. The results of the calculations, in particular, explain why a value in the range of 0.2−0.4 i...

in general, the aerodynamic stability of long span bridges is evaluated based on the results of wind tunnel tests in the low reynolds number region, because in almost all wind tunnel tests, it is impracticable to satisfy reynolds number similitude. therefore, in order to correctly evaluate conventional wind tunnel test results, reynolds number effects on the aerodynamic force coefficients acting o...

In many applications the flow that past bluff bodies has frequency nature (oscillated) and it is not uniform. This kind of flow has effects on the formation of vortex shedding behind bluff bodies. In this paper the flow around a circular cylinder was numerically simulated. The effects of frequency variation at inlet flow on the vortex shedding frequency were investigated. The transient Two-Dime...