In this paper, flow past around two circular cylinders which are tandem arranged at a Reynolds number of 200 is numerically investigated by spectral element method. To validate the numerical method for incompressible Navier–Stokes equations, the benchmark problem of flow over a single circular cylinder is employed, with the numerical results in a good agreement with the available literatures. T...

This paper provides analytical insights into the hypothesis that fish exploit resonance to reduce the mechanical cost of swimming. A simple body-fluid fish model, representing carangiform locomotion, is developed. Steady swimming at various speeds is analysed using optimal gait theory by minimizing bending moment over tail movements and stiffness, and the results are shown to match with data fr...

The flow over the San Antonio class LPD 17 ship is simulated using Computational Fluid Dynamics (CFD) and parallel computers. Both steady-state and time-accurate results are presented for two yaw cases. The computations are done for inviscid flow with no turbulence modeling. Although the flow is highly turbulent and boundary layer effects may not be insignificant, the essential features, such a...

An experimental study on the mixing of two plane, unventilated, parallel jets reveals an instability characterized by sinuous ‘‘flapping’’ of the jets and enhanced mixing of the jets with the ambient fluid. The frequency and amplitude of the instability is shown to be a function of the jets’ spacing and momentum flux ratios, with the maximum mixing occurring for cases with matched momentum flux...

Efficient swimming of biologically carangiform robotic fish has been investigated by using a novel experimental method. The laboratory robotic fish model, which follows an exact replica of Saithe, is self-propelled on a servo towing system. The forward towing speed is determined by the fluid force acting on the robotic fish, as the fish undulates its body in the water. The importance of the sel...

C. elegans is a round worm that lives in wet soil and moves by undulating its body in a sinusoidal wave. We perform experiments on wild-type C. elegans swimming in a granular medium composed of 98 m glass particles and aqueous fluid. Figure 1 shows that a worm swims faster in a granular medium V 0.46 mm /s than in a fluid without particles V 0.37 mm /s . C. elegans in a granular medium undulate...

A model of a high subsonic jet with a nearby array of exible, aircraft-type panels is studied numerically in two dimensions. The jet is excited by a limited duration, spatially localized starter pulse in the potential core. The long time evolution of unsteady disturbances in the jet, the responses of the panels and the ensuing radiation are computed. The results show that the spectral response ...

Fish schools are capable of simultaneous linear acceleration. To reveal the underlying hydrodynamic mechanism, we numerically investigate how Reynolds number $ Re = 1000 - 2000 $, Strouhal St 0.2 0.7 and wavelength \lambda 0.5 2 affect mean net thrust propulsive efficiency two side-by-side hydrofoils undulating in anti-phase. In total, 550 cases simulated using immersed boundary method. The inc...

This article presented an analysis of the pulsatile flow non-Newtonian micropolar (MP) fluid under Lorentz force’s effect in a channel with symmetrical constrictions on walls. The governing equations were first converted into vorticity–stream function form, and finite difference-based solver was used to solve it numerically Cartesian grid. impacts different controlling parameters, including Har...