Abstract: In order improve flow quality of the specific open-jet test section, the design technology of  a certain  low speed wind tunnel open-jet test section was studied using computational fluid dynamics (CFD). It presents the control equations and boundary conditions for numerical simulation. Then the details of numerical results about the different configurations were given. Comparing with full open-jet test section, the velocity uniformity of model region is evidently improved by use of collector. Honeycomb and screens have profound function on the velocity field such as uniformity, direction field and turbulence level. Further investigation on the size of test section and collector  indicates that the flow quality of model region is significantly improved when several measures are implemented such as extending the entrance length before test section, increasing the test section caliber and the changing location and size of the collector. Combination of satisfactory parameters, which can produce a more uniform velocity profile to arrive at the expected level, was obtained based on numerical results.

Key words: low speed, wind tunnel, openjet test section, flow characteristic, numerical simulation, optimal design