On the nonlinear interpretation of a vibrating wire viscometer operated at large amplitude

A non-linear interpretation is proposed for the vibrating wire (VW) viscometer operated with the transient or ringdown method. This new interpretation is motivated by the necessity of having an acceptable signal to noise ratio (SNR) such that a measurement can be performed in 1 s. A large SNR is achieved by a large oscillation amplitude such that the requisite conditions for the linear interpretation are no longer met. We demonstrate the applicability of a new non-linear interpretation with wires of length 40 mm and 50 mm over a viscosity range from 0.3 to 159 mPa s where the maximum amplitude of motion is approximately two thirds of the radius.