non-moving aero grill blocks?

[Old Tele man]

...just got my 1987 edition of HUCHO and while skimming through it, I thought about the patent(s) that Ford had on their new "belt" grills.

...has anybody studied the aero relationships between "sieve" and "shutter" effects of screen-mesh and flat-belt/bar grills?

• At what speed does a mesh-type grill (like the new Cadillac STS, etc.) switch over from acting like a sieve and begins to act like a shutter?

•Same question for the Ford bar grills?

...anybody know what the "describing" empirical equations might be for these two approaches to non-moving aero grill blocks?

[Piwoslaw]

There was a thread about that, sometime last year iirc. I'll try to find it.

EDIT: Here we are:
Solid state drag reducing vehicle grille
Adding grill mesh
grill "shield" rather than block?

[cfg83]

Old Tele man -

I remember that thread too. Pretty sure I posted this on that thread :



CarloSW2

[Old Tele man]

...that's the one, but what's the "cross-over" speed where the air transitions from 'passage' to 'blockage'?

...any rule-of-thumb equation given? I didn't find one on the Ford Patent.

[aerohead]

In 1976,Ford of Cologne,Germany released info on their 'Lamellar' grille which was passive,allowing full airflow at low velocities,the choking the flow down with internal stalling around the grille elements.They claimed a 12% drag reduction,which is the 'typical' drag of the entire cooling system.

[aerohead]

Originally Posted by Old Tele man

...that's the one, but what's the "cross-over" speed where the air transitions from 'passage' to 'blockage'?

...any rule-of-thumb equation given? I didn't find one on the Ford Patent.

I don't recall that they actually ever said.Drat!