Presenter Information

Marshall Philips


Mechanical and Aerospace Engineering

Research Advisor

Finaish, Fathi

Advisor's Department

Mechanical and Aerospace Engineering

Meeting Name

4th Annual UMR Undergraduate Research Symposium (1994: Mar. 23, Rolla, MO)


The purpose of this paper is to measure the velocity profile in the test section of the Variable Density Wind Tunnel (VDWT). The hot wire anemometer is chosen to measure the velocity profile because of its accuracy and its ability to be moved relatively close to the upper and lower surfaces of the wind tunnel. Special attention is paid to the uniformity of flow velocity in the free stream and whether it varies with position in the tunnel. The measurements were taken at two different stations, two different temperatures, and three different speeds.

Results indicate that the velocity profiles are adequate, having small boundary layers and uniform flow in the free stream, for all conditions tested with the exception of the combination of high temperatures and low velocity. At these conditions the flow in the free stream becomes nonuniform making it less desirable for use in father experiments.

The cause of this phenomenon is unknown; however, it could be due to small temperature gradients in the flow. Nonuniform flow temperature may cause density gradients and thus a slight amount of swirling in the flow. This swirling would introduce non-axial velocity components that could become significant at low velocities. Recommendations include further testing at higher temperatures, installing anti-turbulence screens, or avoid doing experiments under the unfavorable conditions altogether.

Document Type


Presentation Date

23 Mar 1994