in general depends upon Reynolds number, but is also dependent on the shape and orientation of the particle with respect to the flow. Charts are available to determine drag coefficient.
(Fig. 29b)
Terminal or settling velocity of a single particle in fluid may be calculated as
If the fluid moves–up with velocity , velocity of the particle with respect to a stationary observer,
, so that the relative velocity or drag remains the same.
depends on
which cannot be directly calculated because the velocity (settling) is not known. Therefore, iteration is required to determine . In the previous lecture, we took-up such an example. However, there is a criterion to check if the settling is in the Stoke’s regime (creeping flow) or in Newton’s region (high flow when inertial effects are important), which is calculated independent of velocity:
in general depends upon Reynolds number, but is also dependent on the shape and orientation of the particle with respect to the flow. Charts are available to determine drag coefficient. 
, velocity of the particle with respect to a stationary observer,
, so that the relative velocity or drag remains the same.
which cannot be directly calculated because the velocity (settling) is not known. Therefore, iteration is required to determine 
. In the previous lecture, we took-up such an example. However, there is a criterion to check if the settling is in the Stoke’s regime (creeping flow) or in Newton’s region (high flow when inertial effects are important), which is calculated independent of velocity:
