Now a days the aerodynamic studies are not constrained to the flow of air past cars
but also a number of other factors like new methods are developed to provide a greater level
of detailed information. Special pressure sensitive paint is now used in the wind tunnel to
graphically show levels of air pressure on a vehicle how it is done is that ,Two different
images are obtained, one at normal room air pressure (wind-off) and a second in which the
wind tunnel is running (wind-on) at a desired test speed. These differences in color, from
wind-off to wind-on, are used to calculate surface pressure.