ABSTRACT
Image-based techniques of flow surface measurements were used to evaluate calculated results by a two-dimensional flow simulation for the 2011 flood of the Ibo River. The target site has a large cobble bar at an abrupt bend, where the flow is made complicated with a transverse step just upstream of the bend and large-sized rocks distributed in its downstream reach. Measurements by techniques such as the Large-Scale Particle Image Velocimetry (LSPIV) and the Space-Time Image Velocimetry (STIV) were used as a bench mark data of the simulation, in which the distribution of roughness coefficient was modified to seek the most probable 2D solution. It was made clear that STIV yields more stable and reliable results than LSPIV even where breaking waves were generated with surface velocity of more than five meters per second. Moreover, the results were successfully used to obtain more appropriate combination of roughness parameters.
