While the majority of models indicate that liquid foaming tends to increase with rising viscosity and decrease with lower surface tension, liquid density, and bubble diameter, it is essential to recognize that these general trends may not universally hold true, as observed in select studies. For instance, Wu et al. noted that foaming height initially increased with viscosity and then decreased with further increase in viscosity. Midoux et al. plotted 𝐿 𝐺 𝜆𝜓 versus 𝐺 𝜆 (𝐿 and 𝐺 are the superficial liquid and gas flow rates, respectively; 𝜆 and 𝜓 are functions of liquid and gas densities, surface tension and viscosity) for various liquids in packed bed reactors. This plot aimed to distinguish between trickling, spray, pulsing, foaming pulsing, and foaming flows. Such a graphical representation is more helpful in identifying the onset and end of different types of liquid flows while changing the liquid properties.