investigation of dune form downstream of inclined and vertical grade control structures in a laboratory model

The study of hydraulic phenomena such as scour and dune formation downstream of grade control structures (gcs), is of high importance due to their direct influence on the stability and life of these structures. this research, conducted through laboratory experiments, aimed to investigate the effects of falling height and downstream face angle on the height and length of dunes formed downstream of the gcs. previous studies have primarily focused on scour holes, while this research delved into the geometric characteristics of dunes. the results demonstrated that the height and length of dunes downstream of a gcs with a 60° downstream face were greater than those with a 90°. additionally, an increase in falling height led to a slight rise in dune height. furthermore, the ratio of dune crest depth to tailwater depth was found to be 0.84, indicating a distinct shape and stability for the formed dunes. the very high correlation coefficient obtained (r=98%) indicates a strong relationship between the variables under investigation, and the r²=96% suggests that 96% of the variations in the dependent variable (dune height or length) can be explained by the independent variables (falling height and gcs downstream angle)