Moderate Swirl Simulation

swirl=.10, viscosity=.0001.


This page shows the moderate swirl simulation in the comparison of 4 simulations. Occasional twin vortices, but usually at most one intense vortex orbiting in the parent vortex.

Maxima in the lower half of the domain. w is vertical velocity, s is speed, q is of sqrt(-2p'/ρ). Data before t=50 is not available. An animation is presented below for 88<t<90, the time spans indicated with the yellow bars. We also take the opportunity in this sumulation to clearly demonstrate the necessity of friction at the lower boundary in making intense vortices: For t>90, the lower boundary is set to free-slip; the multiple vortex and suction vortex phenomena ceases.

Same as above, but showing only 88<t<90.

Below we show more details for frame 84 (time t=89.66), a time of an intense suction vortex. A pressure of -0.5 is the what could be supported hydrostatically by the buoyancy. The p=-0.6 isosurface is reminescent of how the surface of a condensation or debris funnel could appear. Going inside to progessively lower pressure isosurfaces reveals the lowest pressure of -3 is associated with the suction vortex. The final frame shows the windspeed s greater than 2.0 is occuring in a very small region close to the ground, associated with suction vortex with a vertical axial jet with w greater than 2.0.

pressure p=-0.6 isosurface

pressure p=-1.0 isosurface

pressure p=-1.5 isosurface

pressure p=-2.0 isosurface

pressure p=-3.0 isosurface

speed s=2.0 isosurface