|
There are two major types:
Open circuit Windtunnel
If the tunnel discharges its flow to the atmosphere (or laboratory, or pressure vessel, or other unprepared environment) it is called an open-circuit Windtunnel. The Open Circuit Windtunnel has a centrifugal blower
upstream or downstream of the test section.
Figure 2 below shows the schematic of a Open return wind tunnel.
Closed circuit Windtunnel
Closed-circuit tunnels have more uniform flow, in principle, than type (ii), and are the usual choice for large tunnels, but care is needed to maintain good flow at the entrance to the contraction. The flow at exit from the fourth corner (counting from the test section) is typically not much better than the exit flow from a centrifugal blower, although the corner vanes themselves have some effect in reducing turbulence (they can be regarded as honeycombs with walls in one direction only).
Figure 3 below shows the Schematic of a Closed return Wind tunnel.
|
