Check out section 2.9 in this paper: https://www.mdpi.com/2311-5521/5/4/216/pdf
There is also this paper (Reference 9 from above): Jin, G.; Yan, C.; Sun, L.; Xing, D.; Zhou, B. Void fraction of dispersed bubbly flow in a narrow rectangular channel under rolling conditions. Prog. Nucl. Energy 2014, 70, 256–265.