This paper reports the particle image velocimetry (PIV) measurement of swirling flow in a confined rectangular-shaped model combustion chamber. Water is used as the working fluid, and the average profiles of axial, radial, and magnitudes of velocity are given. Flow behavior is investigated and a rebound angle term is defined to investigate the direct effects of the noncircular chamber shape. Flow behavior near the walls is discussed in detail, as are other important swirling flow features such as the appearance of corner and central toroidal recirculation zones. Additionally, experimental data are compared with simulation results. Analyses were performed via commercial software STAR-CCM+ version 9.0. The large eddy simulation (LES) dynamic Smagorinsky subgrid scale, realizable k–ε model, and k–ω shear-stress transport (SST) detached eddy version were used as simulation tools. Three different test filters of 1.0, 2.2, and 3.0 were applied to the LES to identify improvements in accuracy. The overall best turbulence model is compared to the experimental result and reliability of such model is evaluated. The ability of such model was profound within the upstream and to some extent unreliable in downstream.