I review the concept of optimal vortex formation and examine its relevance to propulsion in biological and bio-inspired systems, ranging from the human heart to underwater vehicles. By using examples from the existing literature and new analyses, I show that optimal vortex formation can potentially serve as a unifying principle to understand the diversity of solutions used to achieve propulsion...

The Lighthill acoustic analogy approach combined with Reynolds-averaged Navier Stokes is used to predict the sound generated by unsteady viscous ow past a circular cylinder assuming a correlation length of ten cylinder diameters. The twodimensional unsteady ow eld is computed using two NavierStokes codes at a low Mach number over a range of Reynolds numbers from 100 to 5 million. Both laminar o...

Flow around two tandem cylinders at Re = 3.6 × 106 for different center-to-center spacing ratio (L/D) is investigated numerically using two-dimensional (2D) Unsteady Reynolds-Averaged Navier–Stokes (URANS) equations combined with a standard k−ω SST turbulence model. The instantaneous flow structures the cylinders, hydrodynamic forces on and Strouhal number (St) are analyzed discussed. Dynamic M...

This paper presents a wind tunnel investigation of the aerodynamic characteristics (force and pressure coefficients) static 3:2 rectangular cylinder in smooth flow for angles attack between ?4° 90° at various values Reynolds number. In contrast to much existing literature, this study shows clear dependence mean drag coefficients on addition, variation parameters with angle is fully mapped symme...

Spanwise deviations from a perfect circular cross-section, affect the aerodynamics and hydrodynamics of cylindrical structures. In this study ability novel wavy cylinder, textured to reduce applied drag lift forces is investigated experimentally. Three different configurations proposed geometry, as well bare cylinder with helical strakes are 3D printed tested in an open circuit wind tunnel. Tes...

Abstract This paper presents hot-wire measurements in a wind tunnel, close downstream of basic models blade sections being representative for low-speed, low-Reynolds number axial fans, order to explore the signatures vortex shedding (VS) from profiles. Using Rankine-type approach, an analytical model was developed on velocity fluctuation represented by streets, as aid evaluating experimental da...

Organisms that swim or fly with fins or wings physically interact with the surrounding water and air. The interactions are governed by the morphology and kinematics of the locomotory system that form boundary conditions to the Navier-Stokes (NS) equations. These equations represent Newton's law of motion for the fluid surrounding the organism. Several dimensionless numbers, such as the Reynolds...