  We propose a monolithic Eulerian variational formulation in non-classical
sense of continuum description for the analysis of micro-viscosity parameters
at micro-structural level. In this respect, Cosesrat fluid-structure
interaction CFSI phenomena is taken into account by considering
micro-rotational degrees of freedom of the particles. The governing equations
and variational formulation for CFSI problem are presented. The space and time
domains are discretized by the finite element method and semi-implicit scheme.
The model is implemented and evaluated using FreeFem++. The present model is
analyzed by computing a well known benchmark problem FLUSTRUK-FSI-3*, where the
flow around a flag attached with cylinder is considered for numerical test. The
obtained results suggest that the amplitude of oscillations and
micro-rotational viscosity varies inversely and micro-viscosity parameter
exhibit a significant effect on micro-rotation field as compare to velocity
field.
