Chorin's vortex blob method has been proposed as a way to extend vortex sheet motion past the singularity formation time, into the physically important roll-up regime. Basic questions are: 1. Does the vortex blob method converge to an infinite spiral as the smoothing parameter tends to zero? 2. Do vortex blob computations approximate real fluid motion? This paper will present and discuss three ...

The problem of incompressible steady flow simulation around an airfoil is discussed. For some simplest airfoils (circular, elliptical, Zhukovsky airfoils) the exact solution is known from complex analysis. It allows to compute the intensity of vortex layer which simulates the airfoil. Some modifications of the vortex element method are proposed and test computations are carried out. It’s shown ...

Coherent vortices are an important component of the dynamics of geophysical turbulence, but direct estimates of the properties of the vortex population from measured data is usually difficult. Motivated by this problem, we propose a new method for determining the statistical properties of coherent vortices in two-dimensional turbulence based on a small number of Lagrangian and Eulerian time ser...

Wake vortex encounter risk is a major safety issue in aircraft final approach phase. The evaluation of the risk is crucial when the industry takes the effort to reduce aircraft spacing for the purpose of capacity gain. This paper proposes a hybrid analytical method to assess the wake vortex encounter risk during the final approach phase. The hybrid method uses probabilistic method to calculate ...

We propose an efficient and spectrally accurate numerical method for computing vortex lattice structures in fast rotating Bose-Einstein condensates (BECs) with strongly repulsive interactions. The key ingredients of the method is to discretize the normalized gradient flow under rotational frame by Fourier spectral method in space and by backward Euler method in time. Different vortex lattice st...

This note discusses a rigorous mathematical formulation for the evolution of the Eliassen balanced vortex. It is first shown that a stable balanced vortex of finite extent can be embedded in an ambient fluid at rest, and that such a vortex exists for prescribed angular momentum and potential temperature on fluid parcels. This uses a method developed by Shutts, Booth and Norbury. This is a diffe...

Because of the complexity of the flow field in a trailing vortex, prediction of tip vortex cavitation inception on a hydrofoil or a propeller still relies heavily on model tests and application of cavitation scaling. Experiments indicate that the major parameters influencing tip vortex cavitation inception are fluid viscosity (Reynolds number) and free stream nuclei (Weber number). A scaling me...

Vortices are features crucial for understanding transitional and turbulent flow fields, and have often been visualized using isosurfaces, hulls, and line-like structures. However, they have not been represented in a nonphotorealistic manner that intuitively reflects their local characteristics. We introduce a novel visualization method that represents these features as illustrative vortex cores...

The vortex–in–cell method for three-dimensional, viscous flow was presented. A viscous splitting algorithm was used. Initially the Euler inviscid equation was solved. Following that, the viscous effect was taken into account by the solution of the diffusion equation. The diffusion equation was then solved by the particle strength exchange (PSE) method. Validation of the method was tested by sim...

A particle method is presented for computing vortex sheet motion in three-dimensional flow. The particles representing the sheet are advected by a regularized Biot– Savart integral in which the exact singular kernel is replaced by the Rosenhead– Moore kernel. New particles are inserted to maintain resolution as the sheet rolls up. The particle velocities are evaluated by an adaptive treecode al...