Radial velocity () refers to the component of velocity of a fluid or object in the radial direction, which is directed outward from or inward toward a central point. In the context of a sphere, radial velocity specifically refers to the velocity component along a line that originates at the center of the sphere and extends outward or inward through a point on the sphere’s surface.Â
- is the radial velocity at a point on the surface of the sphere.
- is the free-stream velocity of the fluid far away from the sphere.
- is the angle between the free-stream velocity direction and the line connecting the sphere’s center to the point on its surface.