Comparison of free-surface and conservative Allen–Cahn phase-field lattice Boltzmann method

This study compares the free-surface lattice Boltzmann method (FSLBM) with conservative Allen–Cahn phase-field (PFLBM) in their ability to model two-phase flows which behavior of system is dominated by heavy phase. Both models are introduced and individual properties, strengths weaknesses thoroughly discussed. Six numerical benchmark cases were simulated both models, including (i) a standing gravity (ii) capillary wave, (iii) an unconfined rising gas bubble liquid, (iv) Taylor cylindrical tube, (v) vertical (vi) oblique impact drop into pool liquid. Comparing simulation results either analytical or experimental data from literature, four major observations made. Firstly, PFLBM selected was able simulate purely governed surface tension reasonable accuracy. Secondly, FSLBM, sharp interface model, generally requires lower resolution than PFLBM, diffuse model. However, limit case this not observed. Thirdly, simulations moving FSLBM accurately predicted bubble's shape rise velocity low computational resolution. Finally, PFLBM's accuracy found be sensitive choice model's mobility parameter width.