Transonic Mach number determination in a blow-down windtunnel with solid walls and a downstream throat

Transonic Mach number determination in a blow-down windtunnel with solid walls and a downstream throat

Bannink, W.J.
Bakker, P.G.

Delft University of Technology, Department of Aerospace Engineering

1983-10-31

In this report calibration measurements are described of the transonic flow in the TST27 windtunnel (test section: 28 cm x 25.3 cm) of the Laboratory for High Speed Aerodynamics, Department of Aerospace Engineering, University of Technology Delft. The tunnel has solid walls and the Mach number in the high subsonic and transonic flow regime is controlled by a downstream sonic throat. Along the tunnel centre line the static pressure distribution was measured with a long static tube ranging from the settling chamber to the diffusor; the measurements were made with and without a model in the test section. The model, having a single circular arc profile with a thickness of 2 cm and a chordlength of 10 cm, was mounted on one of the side walls of the tunnel over the full height of the test section. Using the measured distributions of static pressures the distribution of the ratio of the effective sonic cross-sectional area with and without model has been determined. Far upstream of the model (> 14 chordlengths) the above mentioned ratio of sonic cross-sectional areas was constant, meaning that no influence of the model is felt there. In that region reference positions have been chosen in the tunnel side wall, where the pressures will be used to deteinnine the free stream Mach number of the tunnel flow.

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Delft University of Technology

Campus only

Report LR-402

Aerospace Engineering Reports

report

(c) 1983 Delft University of Technology, Department of Aerospace Engineering