High resolution DPIV measurements are made of a vortex ring formed by a piston/cylinder mechanism ~Reynolds number 3700 and 7500!. A complex ring structure is identified. The stopping condition of the piston leads to vortical fluid collecting near the forward stagnation point of the ring. In addition, the roll-up of the core produces a vorticity distribution that departs from a simple Gaussian ...

this paper presents simplified hydrodynamics model for a biomimetic robot fish based on quantitative morphological and kinematic parameters of crangiform fish. the motion of four pangasius sanitwongsei with different length and swimming speed were recorded by the digital particle image velocimetry (dpiv) and image processing methods and optimal coefficients of the motion equations and appropria...

The time-averaged thrust of an incompressible fully pulsed jet containing a period of no flow between pulses is studied experimentally as a function of pulsing duty cycle SrL and the ratio of the ejected slug length (per pulse) to the jet diameter L/D. The parameter ranges investigated were 2 <– L/D <– 6 and 0.1 <– SrL <– 0.98. Significant thrust augmentation by pulsing was observed over the en...

computational paradigm DPIV-driven flow simulation: a new Email alerting service here click or sign up in the box at the top right-hand corner of the article Receive free email alerts when new articles cite this article-We present a new approach to simulating unsteady ®uid ®ows, with only very few degrees of freedom, by employing directly eigenmodes extracted from digital particle image velocim...

The fluid dynamic analysis of animal wakes is becoming increasingly popular in studies of animal swimming and flying, due in part to the development of quantitative flow visualization techniques such as digital particle imaging velocimetry (DPIV). In most studies, quasi-steady flow is assumed and the flow analysis is based on velocity and/or vorticity fields measured at a single time instant du...

The formation of vortex rings generated by an impulsively started jet in the presence of uniform background co-flow is studied experimentally to extend previous results. A piston–cylinder mechanism is used to generate the vortex rings and the co-flow is supplied through a transparent shroud surrounding the cylinder. Digital particle image velocimetry (DPIV) is used to measure the development of...

An experimental investigation of near field aerodynamics of wind dispersed rotary seeds has been performed using stereoscopic digital particle image velocimetry (DPIV). The detailed three-dimensional flow structure of the leading-edge vortex (LEV) of autorotating mahogany seeds (Swietenia macrophylla) in a low-speed vertical wind tunnel is revealed for the first time. The results confirm that t...

Inflammatory bowel diseases (IBD) are driven by imbalances in innate and acquired immune response. In IBD two dysregulated T cell subsets are in the focus of interest: activated effector T cells and regulatory T cells. These T cell subsets are characterized by a strong expression of the ectopeptidases dipeptidyl peptidase IV (DPIV /CD26) and aminopeptidase N (APN/CD13), which are thought to a r...