Quote:
Originally Posted by jthistle
One of the issues with these articles we are finding is the air must flow through the mesh whether it is in a clear pipe like the vent hood article or in a rectangular wind tunnel like the dissertation. So because the air cannot go around as the free hole area decreases the drag is going to increase. If you take this to the limit and have a solid sheet your drag will be infinite because no air will pass. In the case of a grill block the air has the option to flow around the obstruction i.e. up and over your car dramatically reducing the drag. If the test setups in either paper had vents in the structure immediately before the mesh that would give the air someplace else to go then we could directly compare.
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Excellent excellent point.
It would be very nice to find some tests where airflow was allowed to go around and some with angled screens since many grill block will be at slight angles to the airflow.
As far as the mounting setup, that would probably help quite a bit but I do foresee one problem. At highway speeds it's going to be quite a bit of pressure. If you triple the length of the lever you'll need 9x the force to hold it in place. You may have to have the apparatus extend well into the car to be able to hold it in place at full speed.