The models of centrifugal pumps are tested in order to know the performance of the prototypes. Models and prototypes are compared based on geometric similarity, kinematic similarity and dynamic similarity.

When the ratio of all the corresponding linear dimensions of the model and the prototype are equal, then they are said to have geometric similarity. In other words, geometric similarity is said to exist between the model and the prototype, if both of them are identical in shape, but differ only in size.

When the ratio of corresponding velocities at corresponding points are equal, then the model and the prototype are said to have kinematic similarity.

When the ratio of corresponding forces acting at corresponding points are equal, then the model and the prototype are said to have dynamic similarity.