  A microfluidic device is constructed from PDMS with a single channel having a
short section that is a thin flexible membrane, in order to investigate the
complex fluid-structure interaction that arises between a flowing fluid and a
deformable wall. Experimental measurements of membrane deformation and pressure
drop are compared with predictions of two-dimensional and three-dimensional
computational models which numerically solve the equations governing the
elasticity of the membrane coupled with the equations of motion for the fluid.
It is shown that the two-dimensional model, which assumes a finite thickness
elastic beam that is infinitely wide, approximates reasonably well the
three-dimensional model, and is in excellent agreement with experimental
observations of the profile of the membrane, when the width of the membrane is
beyond a critical thickness, determined to be roughly twice the length of the
membrane.
