Experimental study of linear proportional weirs for circle conduit

Proportional weirs in which the discharge is linearly related to the head are known as linear proportional weirs. Because of unit power of their head, linear proportional weirs are more preferable than other traditional weirs in some situations. In this research, based on theoretical concepts different linear proportional weirs having inverted triangular, chimney and two inverted triangular sections were designed. Then, the weirs were constructed and their linear relationship was examined experimentally. 180 runs were conducted to compile the data in the discharge range between 1 and 8 l/s. The data proved the presence of linear relationships for all the examined weirs. The results are shown that relative error of 50%, 66% and 73% of experimental data for inverted triangular weir, chimney weir and two inverted triangle weir are between 1%±. Also, it is observed that the two inverted triangular weir performed better than that of other two weirs, that is, the two inverted triangular weir data had the minimum deviation from its proposed relationship.