http://ir.lib.ruh.ac.lk/handle/iruor/14381 2026-05-14T02:26:03Z 2026-05-14T02:26:03Z http://ir.lib.ruh.ac.lk/handle/iruor/15750 2023-12-22T10:16:36Z 2023-10-01T00:00:00Z

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2023-10-01T00:00:00Z Rengarasu, Terrance http://ir.lib.ruh.ac.lk/handle/iruor/15749 2023-12-22T10:13:22Z 2023-10-01T00:00:00Z

Message of the Editor Rengarasu, Terrance

2023-10-01T00:00:00Z Dassanayake, D.H.H.P. Ahilash, N. Premasiri, A.J.M.S.D. Jayasekara, H.G.H.N. Subramaniam, D.N. http://ir.lib.ruh.ac.lk/handle/iruor/15741 2023-12-22T07:28:14Z 2023-10-01T00:00:00Z

An Investigation on the Shape Factors of Aggregates Dassanayake, D.H.H.P.; Ahilash, N.; Premasiri, A.J.M.S.D.; Jayasekara, H.G.H.N.; Subramaniam, D.N. The aggregate properties such as aggregate size distribution and aggregate shape distribution, affect the mechanical performance of concrete. Although shape of aggregates are computed using various computational methods in researches, it was not clear, which of them define the shape of an aggregate as a whole. This study aims to investigate the shape factors (two-dimensional) in defining the shape of an aggregate. Aggregates of size between 5 – 30 mm diameter were obtained from different batches of aggregate samples that underwent treatment of varied degrees of revolutions in LAAV. Fourteen different shape factors were quantified using image analysis techniques and were tested for ANOVA, regression, principal components and correlation analyses. No shape factor defined the shape of an aggregate individually, while several shape factors were highly correlated. A combination of at least three shape factors is required to define the shape of an aggregate numerically.

2023-10-01T00:00:00Z Meegahakumbura, S.P.S. Jeiroshan, K. Rajendran, K. Mathuwanthy, T. Dias, D.D. http://ir.lib.ruh.ac.lk/handle/iruor/15740 2023-12-22T07:17:49Z 2023-10-01T00:00:00Z

Impact of Influential Parameters on the Formation of Alternate Bars Meegahakumbura, S.P.S.; Jeiroshan, K.; Rajendran, K.; Mathuwanthy, T.; Dias, D.D. At lower discharge rates, channelized alluvial streams frequently exhibit alternate bars. In this study, bar bed forms were regenerated, and checked the sensitivity of parameters governing the formation process of these peculiar bedforms. Resulted water depth, the number of bars, and bar dimensions were measured by varying flow rate, channel slope, and mean grain size of the bed material. The ratio of Shield number to critical Shield number ranged between 2-11, which agreed with previous research findings. The bar length-to-width ratio of alternate natural bars was compared with modeled outputs, which showed an acceptable resemblance. Results revealed that the highest number of bars could be observed for intermediate discharge values (5 − 8cm3/s) when the bed slopes were maintained between 4.5◦ − 7◦. The formation process of these bedforms was signified once particle Reynold number concentrates towards 20. The bar formation process was curtailed beyond a threshold discharge irrespective of the favorable slope and particle Reynolds number, highlighting the sensitivity of the discharge for this phenomenon. Research outputs can be deployed to predict the possibility of bar formation based on the fluid dynamic and morpho-dynamic characteristics of the desired entity when designing reservoirs, hydropower generating schemes, irrigation water supply systems, etc.

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