I am sorry if this isn’t the most fun topic and was written in English, but this is what is taking over my life right now, so can definitely be described as research life! These two weeks I have prepared and conducted the experimental tests in Kashiwa Hypersonic Wind Tunnel. First, let me give a brief overview of my research. I use the pressure sensitive paint(PSP) to measure the surface pressure distribution of the model in wind tunnel. PSP is paint-like coating which fluoresces under a specific illumination wavelength in differing intensities depending on the external air pressure. A backward-facing step(BFS) model is used in this experiment. Flow around the backward-facing step is common in aerospace engineering application.
PSP measurement in hypersonic flows is usually challenged by the severe aerodynamic heating. The original plan was using the BFS model to test the usability of PSP in hypersonic wind tunnel. BFS is a simple geometry where the flow experiences. The PSP painted on the wake area can be free from the aerodynamic heating. The flow over backward-facing step is considered to be two-dimensional by many researchers. I also believed that the flow field would be simple. However, the complex flow structure was capture by the PSP measurement. Three-dimensional effects became the dominating factor of the flow pattern.
The experimental results are sometimes unexpected, but I feel encouraged by unhoped-for finding. To figure out the mechanism of this phenomenon, I decided to change the research direction. Although running a ‘new’ study can be tough, I feel excited about studying this complex flow structure of such simple geometry.