Abstract:
Physical hydraulic model of Nam Haeng spillway and it components was built in hydraulic and coastal model laboratory, Department of Water Resources Engineering, Faculty of Engineering, Chulalongkorn University, in order to study flow behaviors of the spillway chute. Flow profile and flow energy of various discharges were investigated. Comparison of flow energy and flow profiles obtained from model measurement and other two methods of estimation namely, Manning's formula and boundary layer theory were made. In addition, effects of spillway surface roughness on flow energy and flow profile were investigated. Four commercially available sand papers were used as the chute bottom materials. The experiment results indicated that the spillway chute energy losses obtained from the model measurement were higher than the computed values from the Manning's formula and the boundary layer theory. However, flow energy computed from the two estimation methods mentioned above was insignificantly different. Average percent difference of energy losses between model measurement and the other two methods was about 80%. It also found that higher values of spillway chute surface roughness yielded higher flow energy losses and flow profile than the lower values.