The main objectives of this study were to introduce a bubble irrigation system, compare the wetting fronts created by the bubble and free-flow systems, and test the viability of a bubble irrigation system. Two laboratory experiments were conducted using 2D flow to measure the wetting fronts. The first experiment measured the free-flow infiltration using an inverted, open plastic bottle. The second experiment tested the bubble-flow technique using an inverted, closed plastic bottle (ICPB). The results showed that the bubble-flow system created a larger width of wetting fronts at the beginning of the infiltration and then expanded less than that of the free-flow system. In contrast, the infiltration depth of the wetting fronts created by the bubble-flow system was much lower than that of the free-flow system. In conclusion, the wetting front width and depth in the bubble-flow system were slightly smaller than those in the free-flow system. In addition, the wetting fronts created by the ICPB were not moved upwards significantly, which proves the ability of specific distribution of the bubble-flow system on the wetting fronts. Therefore, the bubble irrigation system can be used as an alternative for distributing the moisture content in soil profiles.
Branching channel flow refers to any side water withdrawals from rivers or main channels.
Branching channels have wide application in many practical projects, such as irrigation and drainage
network systems, water and waste water treatment plants, and many water resources projects. In the
last decades, extensive theoretical and experimental investigations of the branching open channels
have been carried out to understand the characteristics of this branching flow, varying from case
studies to theoretical and experimental investigations. The objectives of this paper are to review and
summarise the relevant literatures regarding branching channel flow. These literatures were reviewed
based on flow characteristics, physical characteristics, and modeling of the branching flow.
Investigations of the flow into branching channel show that the branching discharge depends on many
interlinked parameters. It increases with the decreasing of the main channel flow velocity and Froude
number at the upstream of the branch channel junction. Also it increases with the increasing of the
branch channel bed slope. In subcritical flow, water depth in the branch channel is always lower than
the main channel water depth. The flow diversion to the branch channel leads to an increase of water
depth at the downstream of the main channel. From the review, it is important to highlight that most
of the study concentrated on flow characteristics in a right angle branch channel with a rigid boundary.
Investigations on different branching angles with movable bed have still to be explored.
The objectives of this study were firstly, to develop a simulation model (SM) for a single reservoir to identify the standard operating policy (SOP) of a reservoir based on a monthly operating period, and secondly, to evaluate the performance of the proposed Makhoul reservoir using a Developed Simulation Model (DSM) in reducing flood risk. This reservoir is located on the River Tigris, approximately 180 km upstream of Baghdad, Iraq. The performance of the reservoir in reducing flood risk was evaluated using two designs and records of flood waves gathered over two years. The first design was the present one, while the second was developed by increasing the operational storage to its maximum, based on the digital maps of the region. The flows downstream of the reservoir were compared, with and without the reservoir in the two years in question. Four parameters resulting from the two designs were compared: storage, surface area, elevation and power. The results suggested that the reservoir would be ineffective in reducing flood risk, but it would have the ability to provide hydroelectric power using the two designs, with the new one showing better ability at doing this. The reservoir can also serve purposes such as irrigation, fish wealth development and recreation. This DSM proved its effectiveness in evaluating the performance of the single storage system used for reservoirs.
Field surveys of the 2011 Tohoku Tsunami reported massive failures of many seawalls and coastal barriers. The massive damages are vivid evidence that there are flaws in the design of seawalls and barriers. With this as the background, a sequence of laboratory experiments using dam-break waves was performed to simulate the interactions between the tsunami-like bore flow and vertical seawall as well as to measure the bore-induced pressures and to estimate forces exerted on the vertical seawall model. The experimental result revealed that the maximum pressure (approximately 8 kPa) exerted on the vertical seawall was measured at the lowest pressure sensor location. Experimental data were used to re-examine the relevant empirical formulae found in the literature. The obtained results could be useful for calibrating mathematical and numerical models as well as for future research concerning the design of tsunami barriers.
Experimental data from a physical model of scouring around a cylindrical wide pier embedded in two
types of uniform sediment beds are presented. The effects of sediment sizes and various pier widths on
scour development and equilibrium scour depth of wide bridge piers are described. Existing literature
suggest that the empirical scour prediction equations based on laboratory data over-predict scour depths
for large structures. The present study has attempted to fill this gap for a cylindrical wide pier. Further,
equations for the estimation of non-dimensional maximum scour depth for a wide cylindrical pier
embedded in uniform sediment were proposed as functions of the sediment coarseness.