[Tugger]

In order to gain experience in visualising air flow, "Feeling" turbulence when trailing vehicles on a motorbike, is a HUGE help, as is designing a simple wind tunnel., to visually seek out the turbulent flows, from the less than ideal designs, that produce a turbulent wake and flow separations.

And to declare that a simple kitchen top as worthless, as both a scientific instrument and research tool, simply because the "real ones" cost millions of dollars.

You see my well intentioned friend - the only difference between what you call a worthless junk kitchen table wind tunnel and a "real wind tunnel" - costing millions of dollars, are two things, size and air velocity.

And a simple wind tunnel, is a great aid to the imagination.....

I map thermal gradients and air flows, from the stratified air layers in my own home with an incense stick.

The cooler night air coming in, filling up the rooms from the bottom, as the warm air runs out under the tops of the doorways, and vis versa in the morning when the sun rises and the air outside becomes warmer than the air in the house.

All of the air flows, and turbulence from the delaminating boundary layers, projections etc - everything, can be tracked using an incense stick, in air velocities as low as 1/4 of walking speed.