“Velocity for upstream” generally refers to the speed of a fluid or object in a direction opposite to the flow of the fluid or the movement of the object. In fluid dynamics, the term “upstream” refers to the direction against the primary flow of the fluid.
- : is the velocity of upstreamÂ
- M2: is the Mach number of upstreamÂ
- a2: is the speed of sound in upstreamÂ