Fluid-solid Interactions
Biological materials such as smooth muscle tissue, lung tissue, heart tissue have
compliance such that they deform under mechanical strain or fluid
pressure. A multiscale computational framework is being developed for
integrating subcellular responses at the nanoscale level with
structural modifications in the tissues and airways. A framework also
is being developed for coarse graining and averaging cell properties
for incorporation into large deformation finite element simulations of
the tissue. Coupled field analysis is being performed on the tissue
model by taking the interaction between the fluid and solid parts. The
fluid part is solved using the FLOTRAN solver of ANSYS, the impact of
which on the tissue structure is determined with the coupling of two
media. The analysis is performed sequentially by solving the fluid
media first using the FLOTRAN macro of ANSYS. The pressure loads from
the fluid are in turn applied on the structure, which deforms under the
fluid pressures. As a result, the fluid mesh is updated based on the
structural deformation and this is carried in an iterative manner until
the equilibrium (which is specified by the user) is reached. FSSOLV
macro provided by ANSYS was used to perform the analysis. When the
solid part is assumed rigid, the interaction is ignored and only the
flow analysis is performed. Currently, the fluid-structure interactions
are being carried out by coupling ANSYS with CFX through a flexible
interface using a distributed computing environment.