The lecturer from the Department of Structural Engineering and Water Resources at the Faculty of Engineering / the University of Kufa, Dr. Fadel Abdul Abbas, participated in the second international conference of civil and environmental engineering technology, with the research entitled: “CFD based model to identify the minimum length of a gradual rectangular expansion operated under supercritical flow”. This conference, organized by the University of Kufa in cooperation with the Faculty of Engineering / Civil Engineering Department, is held on the virtual free conference call.
The researcher explained that the computational fluid dynamics program (CFD) was used to derive a mathematical model to link the length of the gradual expansion (Le) with other hydraulic and engineering factors for flow in rectangular channels under supercritical flow conditions. The program simulated five models of different lengths and expansion lengths of 30 cm, 50 cm, 75 cm, 100 cm, and 125 cm in the CFD v18.2 program and was verified by practical data which was measured in the laboratory results. Pointing to the treatment of all models of CFD programs based on the model (K-epsilon), while the finite element was built by the Multi-Zone method.
The researcher indicated that five velocity values were applied at the entrance to the simulation model (V-inlet) and for each model are 1.5 m/s, 1.6 m/s, 1.7 m/s, 1.8 m/s, and 2 m/s, as measured Water depths along the channel in multiple sections, before expansion (y1), and within expansion (yc) and after expansion (y2). While the results of the program analysis showed that the minimum length of expansion to maintain the flow within a supercritical range was 0.35 m and the (Le/W) ratio was 1.167. The results of the two-dimensional relationship were compared with the laboratory results. The comparison showed a good statistical correlation, where the highest difference between the two groups of results was 13.8%. While the determination coefficient (R2) for this equation was 0.973.