Advective balance in pipe-formed vortex rings

  title={Advective balance in pipe-formed vortex rings},
  author={Karim Shariff and Paul S. Krueger},
  journal={Journal of Fluid Mechanics},
  pages={773 - 796}
Vorticity distributions in axisymmetric vortex rings produced by a piston–pipe apparatus are numerically studied over a range of Reynolds numbers, $Re$ , and stroke-to-diameter ratios, $L/D$ . It is found that a state of advective balance, such that $\unicode[STIX]{x1D701}\equiv \unicode[STIX]{x1D714}_{\unicode[STIX]{x1D719}}/r\approx F(\unicode[STIX]{x1D713},t)$ , is achieved within the region (called the vortex ring bubble) enclosed by the dividing streamline. Here $\unicode[STIX]{x1D701… 

Viscous vortex layers subject to more general strain and comparison to isotropic turbulence

Viscous vortex layers subject to a more general uniform strain are considered. They include Townsend's steady solution for plane strain (corresponding to a parameter a = 1), in which all the strain



A universal time scale for vortex ring formation

The formation of vortex rings generated through impulsively started jets is studied experimentally. Utilizing a piston/cylinder arrangement in a water tank, the velocity and vorticity fields of

A family of steady vortex rings

  • J. Norbury
  • Physics, Mathematics
    Journal of Fluid Mechanics
  • 1973
Axisymmetric vortex rings which propagate steadily through an unbounded ideal fluid at rest at infinity are considered. The vorticity in the ring is proportional to the distance from the axis of

Reynolds‐number Effect on Vortex Ring Evolution

An analytical model describing a vortex ring for low Reynolds numbers (Re) proposed previously by Kaplanski and Rudi [Phys. Fluids,17, 087101 (2005)], is extended to a vortex rings for higher

The formation of ‘optimal’ vortex rings, and the efficiency of propulsion devices

The formation of an axisymmetric vortex ring by forcing uid impulsively through a pipe is examined. An idealized model of the circulation, impulse and energy provided by the injected plug is

A numerical study of viscous vortex rings using a spectral method

Viscous, axisymmetric vortex rings are investigated numerically by solving the incompressible Navier-Stokes equations using a spectral method designed for this type of flow. The results presented are

A model for universal time scale of vortex ring formation

An analytical model for predicting the universal time scale for formation of vortex rings generated through impulsively started jets is considered. The model is based on two assumptions, namely the

Energy and velocity of a forming vortex ring

It is known that vortex rings formed by large stroke ratios (in a piston/cylinder arrangement) pinch off from their generating jets at a fairly constant universal time scale. In this paper we show

A model for the formation of optimal vortex rings taking into account viscosity

The evolution of a viscous vortex ring from thin to thick-cored form is considered using an improved asymptotic solution, which is obtained after impressing a spatially uniform drift on the

Motion and expansion of a viscous vortex ring. Part 1. A higher-order asymptotic formula for the velocity

A large-Reynolds-number asymptotic solution of the Navier–Stokes equations is sought for the motion of an axisymmetric vortex ring of small cross-section embedded in a viscous incompressible fluid.

On steady laminar flow with closed streamlines at large Reynolds number

  • K. G.
  • Physics, Engineering
  • 2005
Frictionless flows with finite vorticity are usually made determinate by the imposition of boundary conditions specifying the distribution of vorticity ' at infinity '. No such boundary conditions