DRAG NEGATIVE HELPING VEHICLE MOVEMENT ????
There are many types of aerodynamic resistance: friction, shape, pressure, etc ....
Normally, drag opposes the movement of the vehicle. This is so. But there are cases of car parts where there are NEGATIVE drag:
We analyze the next vehicle:
The vehicle in CAD:
If we show the drag in Kg, of every vehicle part, we see that the up zone of screen, have DRAG POSITIVE:
Inventor/ Speed-adaptive wing for drag reduction / Patent 9,266,571 and patent 9,994,265.
8 年How much does it cost for cfd testing?
Refrigeración en Toyota Motor Corporation y co-fundador de FANSI Motorsport.
8 年That part of the roof indicated by the arrow reminds me of leading edge suction seen on airfoils, https://images.slideplayer.com/26/8865395/slides/slide_21.jpg, but there's still a net positive drag. Also, an infinite cylinder in an inviscid flow has patches of negative drag, but the pressure-drag term integrated over the closed surface yields zero (D'Alemberts paradox). Adding to Willem Toet's coment, I'm certain we can find negative drag in any front facing curved area (which is the common thread among the van's roof top, the airfoil and the cylinder); but when talking drag I consider the key concept is closed surface.
Fluids and Thermal Engineering Consultant
8 年I think this violates a number of basic laws of physics: Newton's 3rd law, 1st law of thermodynamics ... just few to spring to my mind.
Web: timoteobriet.com MATEMáTICO, AERODINáMICO, INGENIERO CFD.
8 年Would be the best invention in the world ... the FULL drag in any vehicle, always is positive. Thanks a lot Willem Toet is a pleasure.
F1 and Aerodynamics Expert. Over 30 years in F1 Aerodynamics, now Professor of Motorsport Engineering (UoB), Aerodynamics Advisor & Consultant, former F1 Head of Aerodynamics at Sauber, Ferrari, Benetton, BAR Honda
8 年Yes there are always parts of a vehicle that have negatie drag. Even on a formula one car. Hoever that same part used alone and in isolation always have positive drag (even though parts of it may still negative drag. If anyone can invent a complete body with negative drag, they will be very rich indeed! Willem Toet