SAE J2971:2019 pdf free
SAE J2971:2019 pdf free.Truck and Bus Aerodynamic Device and Concept Terminology
FLOW CONTROL: A system that modifies the mass, momentum, or energy of the flow to modify the aerodynamics of the vehicle. Control may be passive or active including control schemes, sensors, and feedback loops. The adjectives “passive” or“active” may be used in concert with the device type terminology specified in Section 4. Examples of passive flow control devices include static geometric shaping, vortex generators, grooves, riblets, surface roughness, vents, diverters, etc.
Examples of active methods includes dynamic boundary layer separation control, vortex control, morphing, oscillating,rotating, flapping, jetting, etc.
REYNOLDS NUMBER: A dimensionless number that gives a measure of the ratio of inertial forces to viscous forces and consequently quantifies the relative importance of these two types of forces for given flow conditions.
SEMI-TRAILER: Trailer supported at the rear by its own wheels and at the front by a fifth wheel mounted to a tractor or dolly.
SEPARATION POINT: A point where the boundary layer flow becomes detached from the surface.
SLOT (Aerodynamic Gap): Longitudinal distance between the aft most point of the cab external surface, including aerodynamic side fairings, and the forward most point of the cargo carrying portion of the vehicle.
STAGNATION LINE: A location on the surface where the fluid is brought to rest (zero velocity).
TRACTOR: A vehicle designed primarily to pull a semi-trailer by the use of the fifth wheel that is mounted over its drive axle(s). May be called a truck/highway tractor to differentiate it from a farm tractor.
TRAILER: A freight carrying unpowered unit pulled by a powered unit.
TRUCK: A vehicle which carries cargo in a body (van, tank, etc.) which is mounted to a chassis, possibly in addition to a trailer which is towed by the powered vehicle.
TRUCK-TRAILER: A truck-trailer combination consists of a truck that holds cargo in its body which is connected to its chassis, and which tows a trailer.SAE J2971 pdf free download.
