CFD modelling of pressure and shear rate in torsionally vibrating structures using ANSYS CFX and COMSOL Multiphysics

Abstract

This paper discusses numerical methodologies to simulate micro vibrations on a nontrivial torsionally oscillating structure. The torsional structure is the tip of a viscosity-density sensor using micro vibrations to measure the fluid properties. A 2D transient simulation of the fluid domain surrounding the tip of the sensor has been conducted in ANSYS CFX and COMSOL Multiphysics software. ANSYS CFX uses a frame of reference to induce the micro vibration whereas a moving wall approach is used in COMSOL Multiphysics for the full Navier-Stokes equation as well as their linearized form. The shear rate and pressure amplitude have been compared between the different numerical approaches. The obtained results show good agreement for both pressure and shear rate amplitudes in all models.