Week 2 - Flow over a Cylinder.

VORTEX SHEDDING

Below figure shows the vortex shedding occurred when air like fluid passes the blunt body. vortex shedding which occurs in the wake region when fluid passes the bluff body, then alternate swirls are formed in the wake region at certain frequency. The alternating vortices formation creates the alternate forces at the shedding frequency. The frequency increases as the flow increases. The shedding frequency should be estimated to know whether it will match natural frequency of the body and creates the resonance.

In fluid dynamics the Karmen-Vortex street is a repeating pattern of swirl vortices, caused by a process called vortex shedding, which is responsible for the unsteady separation of flow of a fluid around the blunt body.

STROUHAL NO:

Strouhal no is the ratio of inertial force due to unsteadiness in the flow or local acceleration to the inertial force due to change in velocity from one point to another in the flow field when fluid passes the bluff body