Flow Field over the Rubber Dams Based on Fluid-Structure Intractions

Rubber dams are flexible cylindrical structures, attached to a rigid base, and are inflated with air and/or water. Most of the rubber dams are permanently inflated, however, they have the advantages of deflating and being flat, when they are not needed, and then inflated in a short period of time when they are required. Large deformation of the membrane due to the internal and external loads, makes the governing equations of such problem to be non-linear and complicated. In the present study, three-dimensional behavior of the rubber dams with respect to the boundary conditions of dam and flow was simulated numerically. Dam geometry and flow hydraulics were modeled, using ANSYS software, CFX and transient structural in workbench environment, simultaneously. Flow hydraulic characteristics and deformation of the dam are obtained, considering fluid-structure interaction. Water free-surface was obtained, applying two-phase air-water flow interface. SST turbulence model in CFX was employed for modelling the separation of flow, downstream of the inflatable dams. Due to the flexibility of the structure, large deformation theory was used in the transient structural solution. Consequently, different features of the flow field, including flow streamlines, velocity and pressure profiles are obtained and compared with those of the rigid circular-crested weirs. Results indicated that the flow hydraulic characteristics over the equilibrium shape of the rubber dams is analogous to those of the rigid circular-crested weirs.