Oblique weir equation using incomplete self-similarity

Incomplete self-similarity (ISS) concept is employed to develop the equations from existing experimental results of flow over an oblique rectangular sharp-crested weir for both free and submerged flow. The stage-discharge relationship is obtained by theoretical analysis, based on the application of the dimensional analysis and the ISS theory. For analysis, the relations were found by trial and error procedure using the SPSS mathematical computer program that estimates the relation among multi-variable functions. Thus, equations to estimate the flow characteristics for both free and submerged flow are proposed. The results show a better compatibility with the experimental data than the previous equations given by the main author. Hence, the capabilities of ISS method for similar analysis and the powerful program of SPSS for multi-variable data analysis is shown. Finally, design guides together with examples are presented to show the simple use of the graphs obtained . Key words: dimensional analysis, incomplete self-similarity (ISS), oblique weir, experimental data.