BiconeDrag updated – A data processing application for the oscillating conical bob interfacial shear rheometer

We present a new improved version of BiconeDrag, a code that allows one to obtain the values of interfacial dynamic moduli from dynamic experiments performed in rotational interfacial shear rheometers with bicone probes. The general structure of the program remains the same: starting from the values of the torque/angular displacement amplitude ratio, and by using the equations of the hydrodynamic field, it is possible to decouple the contribution of the subphase (bulk) drag from the true interfacial drag. In this new version we have improved the implementation of the boundary condition at the interface so that now it is built as second order centered finite differences (SOCFD hereafter) with the help of a line of phantom nodes. The new numerical implementation of the interfacial boundary condition yields smoother velocity profiles at the bicone rim, which result in a more accurate separation of interfacial and subphase drags and, consequently, in a more precise calculation of the interfacial dynamic moduli.