Bends contribute to a flexible layout of pipeline system, but also lead to intensive energy costs due to the complex flow characteristic. This experimental study is conducted to investigate the impact of a single coarse particle on the flow field in a bend. The velocity profiles of fluid on the axial symmetry plane of the bend are measured using time-resolved particle image velocimetry. The flow structures are extracted using the proper orthogonal decomposition method. The results reveal that there is a shear-layer flow in the bend during the transportation. With the increase in particle size, the particle has a dominant influence on the flow energy distribution of the overall flow. The impact of particles on the first few energetic flows is mainly in the latter part of the transportation, both temporally and spatially. As the particle size decreases, the most energetic unsteady flow within the bend changes from the convective flow to the flow of the shear layer.