Bubble rise dynamics in a quiescent liquid and impact on a cylinder

This study investigates the dynamics of a single bubble rising in a quiescent liquid and impacting a fixed cylinder using a resolved two-fluid approach. The resolved two-fluid approach is validated against experimental data and compared with a one-fluid approach through 2D axisymmetric and 3D simulations across a wide range of Reynolds and Eötvos numbers, and density ratios. The two-fluid model accurately reproduces the bubble shape, terminal velocity, and impact dynamics, showing agreement with both experimental observations and the one-fluid approach. A detailed analysis on the impact force coefficient exerted by the bubble on the cylinder is conducted with the two-fluid approach by varying the bubble’s Reynolds and Eötvos numbers and the density, viscosity, and bubble-to-cylinder diameter ratios (Re_b∈[1,80],Eö∈[10,116],ρ_l/ρ_g∈[25,1000],μ_l/μ_g∈[10,100], and d_b/D_c∈[0.5,1.0]). This study reveals that, when varying one dimensionless number at a time, the bubble Reynolds number has the most significant influence on the impact force coefficient, followed by the bubble-to-cylinder diameter ratio and the Eötvös number, while the effects of viscosity and density ratios are weaker. A correlation on the impact force coefficient (associated to the force applied by the bubble on the cylinder at impact) is proposed and may be useful for Euler–Lagrange point-particle methods.