Digital Terrain Models (DTMs) represent an essential source of information that can allow the behaviour of the urban floodplain, and its interactions with the drainage system, to be examined, understood and predicted. Typically, such data are obtained via Light Detection and Ranging (LiDAR).If a DTM does not contain adequate representation of urban features the results from the modelling efforts can be. This is due to the fact that urban environments contain variety of features, which can have functions of storing and/or diverting flows during flood events. The work described in this paper concerns further improvements of a LiDAR filtering algorithm which was discussed in a previous work. The key characteristics of this improved algorithm are: ability to deal with buildings, detect elevated road and represent them accordance to reality and deal with bridges and riverbanks. The algorithm was tested using a real-life data from a case study of Kuala Lumpur. The results have shown that the newly developed MPMA2 algorithm has better capabilities of identifying some of the features that are vital for urban flood modelling applications than any of the currently available algorithms and it leads to better agreement between simulated and observed flood depths and flood extents.
There are various sources of energy throughout the world, renewable as well as non-renewable through which renewable energy sources are considered more environmentally friendly. Encompassed by all the sources of renewable energy, hydropower is considered the most beneficial source of energy. Proper operation of hydropower plant is very important for generating maximum energy by utilizing the available. However, formation of vortices at power intake can cause number of problems. The stronger vortices have more negative effects on the performance of hydropower plant which can also, draw debris and air into an intake causing vibration and damage to turbines. The present study addresses the vortices formation at the intake dam, several types of vortices and anti-vortex applications in order to overcome the vortex formations.
The formation of vortex and swirling in any flow structures of the hydropower dam is undesirable, as it reduced the performance of turbine as well as lowered the efficiency of hydroelectric power generation. Furthermore, it could lead to the hydraulic losses at the entrance of power intakes, the blockage at the trash racks due to entrain debris and the reduction of the working life of turbines. This paper studied penstocks flows in the dam intake section numerically. The dynamics of penstocks flows at different operating conditions were analyzed to determine the vortex formation. To access the veracity of the current proposed numerical model, a validating study based on the particle image velocimetry (PIV) experiment was conducted. It was found the discrepancy between both numerical and experimental flow velocities is 12%, implying the numerical model is well-validated and the corresponding findings are acceptable. It was found that the vortex was formed in the penstock that located at the lowest level relative to other penstocks. Furthermore, the highest pressure of 4 MPa was recorded at the bottom section of the penstock which observed vortex. This numerical work provided useful insights for the future dam reliability analysis, particularly involving penstocks and intake section.
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