Towards Quantitative Wall Shear Stress Measurements: Calibration of Liquid Crystals
2020
The wall shear stress distribution on an aerodynamically loaded component is of both practical and fundamental importance. Significant examples are the improvement of the performance of a vehicle, e.g. drag reduction, and more basic problems, such as the characterization of surface flows, e.g. with respect to flow control. The liquid crystal technique represents a promising diagnostics for measuring wall shear stress magnitude and orientation. In contrast to most other techniques, the direct measurement of two-dimensional wall shear stress distributions is straightforward.
In order to establish quantitative measurements of wall shear stress using the liquid crystal technique, an in-depth understanding of the influencing parameters is required. For their investigation, a novel generic flat plate test section was designed. The experiments are performed in such a way that a turbulent boundary layer is triggered at a corresponding Reynolds number within the test section. Due to the generic test case, precise and well-known flow boundary conditions can be established, which in turn are validated by probe measurements. Velocity and temperature profiles are recorded with high spatial resolution using a miniaturized combined Pitot-thermocouple probe. Furthermore, the operational range of the new test rig is presented. Preliminary wall shear stress measurements confirm the well-defined flow conditions in the test section and the potential of the measurement technique.
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
0
References
0
Citations
NaN
KQI