We present the computational results of the dynamics of single bubbles slowly formed from a submerged nozzle in a viscous liquid. Our simulations are carried out by a sharp interface coupled level set/volume-of-fluid (CLSVOF) method and the governing equations based on the CLSVOF method are solved through a hydrodynamic scheme with formal second-order accuracy. The application of two-phase computational fluid dynamics (CFD) for simulating bubble formation dynamics in a viscous liquid is a challenging task. We present unique, quantitative, comparisons between the results from CFD and experimental observations. As a result, it is shown that our computational method is robust to extreme variations in physical properties and extreme variations in interfacial topology, and it is shown that our method gives accurate results.