Initial Velocity – Source

– Multiplier for inherited velocity. A value of 1 will emit smoke moving at the same speed as the source.
– Note: this is only the INITIAL VELOCITY! After the emission both smoke and fire follow their usual behavior.

– In this video the effect for Source = -2.0 is more evident during the ascending motion (the resultant Initial Velocity vector is opposite to the ascending flow).

– Another example: I set Temperature Difference = 0 so that the smoke does not move away from its poit of origin unless it has some velocity.
– During the firsts 50 frames the flow emitter doesn’t move, all fire and smoke emitted don’t move from their origin.
– For Initial Velocity = 0 you obtain a very weird effect, of course as both smoke and fire are emitted with no velocity, they don’t move from their points of emission.

Blender Smoke Initial Velocity Source