A new method of detection and measurement of quantum vorticity by scattering second sound off quantized vortices in superfluid Helium is suggested. Theoretical calculations of the relative amplitude of the scattered second sound waves from a single quantum vortex, a vortex ring, and bulk vorticity are presented. The relevant estimates show that an experimental verification of the method is feas...

We give an elementary proof of the convergence of the point vortex method (PVM) to a classical weak solution for the two-dimensional incompressible Euler equations with initial vorticity being a finite Radon measure of distinguished sign and the initial velocity of locally bounded energy. This includes the important example of vortex sheets, which exhibits the classical Kelvin-Helmholtz instabi...

Background The vortex ring formed in the left ventricle (LV) of the human heart during early diastolic inflow (corresponding to the Doppler E-wave) contains information about the normal and pathophysiologic aspects of diastole. Previous studies suggest that the volume of the vortex ring is an important characteristic of vortex ring formation. However, due to lack of quantitative methods, vortex...

The generation of initial or inflow synthetic turbulent velocity scalar fields reproducing statistical characteristics realistic turbulence is still a challenge. eddy method, previously introduced in the context conditions for large simulations, based on assumption that can be regarded as superposition coherent structures. In this paper, new type method proposed, where fundamental constructed b...

In this thesis we investigate the locomotion of fish and birds by applying both new and well known mathematical techniques. The two-dimensional model is first studied using Krasny’s vortex blob method, and then a new numerical method based on Wu’s theory1 is developed. To begin with, we will implement Krasny’s ideas for a couple of examples and then switch to the numerical implementation of the...

In this paper, the eigenmode linear superposition (ELS) method based on the regularization is used to discuss the distributions of all eigenmodes and the role of their instability to the intensity and structure change in TC-like vortex. Results show that the regularization approach can overcome the ill-posed problem occurring in solving mode weight coefficients as the ELS method are applied to ...