NUMERICAL PREDICTION METHOD FOR MULTIPHASE FIELDS TO PREDICT FLUID FORCES ACTING ON MULTIPLE RIGID CYLINDERS

摘要

The applicability of a computational method was investigated to predict the fluid forces acting on multiple rigid cylinders in wave-induced flows. The free-surface flows including cylinders are treated as incompressible gas, liquid and solid fields in the computational method, MICS (Multiphase Incompressible flow solver with Collocated grid System), which is a solver for multiphase fields. The solid objects included in the flows are represented by tetrahedron elements. The areas occupied by the elements are modeled as the incompressible fluids which have the same densities as the solid objects. The basic equations for the modeled fluids are discretized with a finite volume method on a collocated grid system and they are solved with MAC procedures. The fluid forces against the objects are estimated with the volume integral of the momentum equations for the solid areas. The prediction method was applied to the experiments, in which a water tank equipped with multiple cylinders was accelerated in one direction and the fluid forces on the cylinders were measured by means of strain gages. As a result of the computations, it was confirmed that the predicted time-histories and peak values of the fluid forces are generally in good agreement with the experiments. By making comparisons with experimental results, the applicability of the computational method was discussed.