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Old 04-15-2017, 12:43 PM   #24 (permalink)
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Originally Posted by ChazInMT View Post
We can all relate to fans moving air and requiring energy to do so right???

Anyone here who does not believe a fan needs to be plugged in, using energy to turn a motor, which turns the fan blade, that makes a certain volume of air move??? Raise your hand now, and then quit reading because you're too dumb to comprehend anything.

So, if a fan requires energy to move air......we can assume that causing air to move requires power.

A truck moving through still air is going to cause the air to move, right?? Air needs to be pushed up and aside. A lower pressure area behind the truck is going to need to be filled in, causing air to rush in to fill the void so to speak. The air moving up and sideways is going to push the air beside and above the truck for tens of feet sideways and up, and the air will swirl about for many seconds after the truck has passed, seeking to be still again. Anyone driving behind a truck on a narrow road sees this happening on the grassy fields beside the road and the leafy trees overhanging it. All this jostling of the air is no different than a fan, the air is being forced to move, and how much it moves is the energy required to keep the truck moving. That is what drag is. It is the energy required to make still air move.

Please, anyone, enlighten me on how this concept of plasma makes the air move less?
It looks like the authors are trying to create the effect of VGs to mitigate the crosswind-induced separation bubble on the leeward side of the vehicle.

During calm conditions the 'VGs' aren't 'there',and there's no drag penalty as you'd have with say AirTabs.
For them to work though,they need to 'move' around on the body,in accordance with a fluid battle field of transient flow separation,as a function of degree of yaw.
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