Application of 3 component Laser-Doppler Velocimetry in transonic flow over a Delta wing

Kurzfassung

In the development of numerical codes for the prediction of aerodynamic flows is a strong need to obtain reliable flow field data which is suited to validate turbulence models used in Navier-Stokes calculations. In three dimensional boundary layers Laser-Doppler Velocimetry (LDV) is the appropriate technique usually applied to obtain this kind of data. Since LDV, being a single point measurement technique, is a time consuming method, it is desirable to have the ability to make use of data from different experiments and research groups. Therefore it is necessary to have a standard to compare experimental results obtained by different LDV processors and to define a consistent mathematical algorithm to process data from the different LDV experiments. This is the objective of the present paper. In an European activity four different research groups have conducted common experiments in industrial wind tunnels and finally compared the results to qualify LDV for the application in industrial wind tunnel and to define a standard to compare LDV data coming from different sources. Velocity data as well as turbulent quantities have been successfully acquired close to the surface of the model. The obtained experimental data show the 3D Laser Doppler Velocimeter set-up has been successfully adapted to the investigation in transonic flows. The comparison of the two transformation matrixes obtained by the two different systems leads to the results that the both system show no significantly different transformation matrix. To compare the velocity data obtained by the different processors a common mathematical algorithm has been applied by all groups. Finally an extensive comparison of the data obtained by the different systems has been made