Author(s): D. Legono; A. P. Rahardjo; A. Hairani
Keywords: Hydraulics simulation; Energy losses; Stratified pipe; Experimental study
Abstract: The Jakarta flooding is getting more severe that number of locations being inundated, frequency of inundation, intensity of inundation, and unfortunately number of affected peoples have been increasing significantly. So far has not been investigated intensively regarding the performance of both macro system (the thirteen river systems in Jakarta) and the micro system (local drainage system) during the flooding period. It is obvious that the inundation might be caused by insufficient capacity of both systems to accommodate the heavy rainfall in the watershed system. An idea of introducing flood way of Ciliwung River by mean of underground tunnel is considered attractive because the land utilization is minimized. However, the hydraulic performance of such tunnel should essentially supports the reduction of flood disaster risk of Ciliwung River. This paper presents the result of hydraulic study of flow through stratified pipe as revealed by laboratory experiment as initial step to investigate the function of the aforementioned underground tunnel. The Bernoulli equation applying primary and secondary losses has been initially studied to predict the losses over the entirely flow over underground tunnel pipe course. Flow behavior by means of vortex around the transitional cross-section (both inlet and outlet), pressure distributions along the pipe flow, and friction losses along the pipe flow was studied applying the image processing techniques. The results of the experimental study show the complex behavior of flow over the stratified pipe flow and thus also the impractical utilization of further similar system as the underground tunnel to manage the flooding problems. Further discussion regarding the operation and maintenance of the stratified pipe for the underground tunnel utilization is also discussed and suggests the improper use of such system to solve the flooding problem in Jakarta area.