Extensional flow is defined as flow which is created by pulling on a molten polymer and it can happen on contraction situations. Whereas, shear flow is used in solid mechanics and in fluid dynamics.
In extensional flow, velocity is 0 at stagnation point , whereas in shear flow, there is no such points.
In extensional flow, there is possibility of stretching and also possibility of breakage and in shear flow effects are transient.
