Comparison of background-oriented Schlieren and retroreflective shadowgraph visualizations of sand burner fire
Year: 2025
Type: article
Abstract: Simultaneous records of background-oriented schlieren (BOS) images and retroreflective shadowgrams (RS) of a stationary sand burner flame are compared to demonstrate the capabilities of each method. The schlieren images from the BOS method are post-processed in the PIVlab software via the reference image sequencing style method. The shadowgrams obtained in the RS setup are enhanced by adjusting the levels and contrast of the images. The range of length scales, the spectra at each length scale, and the effect of a glass sidewall window on the resolution of the images are determined. Adding glass as a sidewall will reduce the resolution and thus the number of detected eddies, but dominant eddies with their energy will remain unaffected. In addition, the convective heat transfer is calculated and analyzed for both visualization methods. The results show that, in the described system, the resolution of the BOS images is lower than that of the shadowgrams, so smaller eddies are not as clearly visible as in corresponding RS results. However, BOS has the advantage of more easily quantifying the parameters studied in the present work. The paper also describes a method to extract the heat transfer contours from shadowgrams, which complements a similar approach in which heat transfer is obtained from BOS images.
Institutions: UNSW Canberra, UNSW Sydney, Worcester Polytechnic Institute
Language: English
Subfield: Computational Mechanics
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,720
OpenAlex ID: W6903301222