Browsing by Author "Rao, N.B.S."
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Item A laboratory investigation on a single row of suspended porous pipes is conducted in a two-dimensional wave flume to study their hydraulic performance under regular wave attack. The wave energy losses are computed and the effects of porosity, water depth, incident wave steepness and relative wave height on loss coefficient are studied. It is found that loss coefficient increases with an increase in incident wave steepness. Water depth has insignificant effect on K1 when wave steepness is varied. It is also observed that as porosity increases K1 decreases. For the range of variables studied, as the relative wave height increases, K1 decreases.(Energy dissipation in suspended porous pipe breakwaters in laboratory) Rao, S.; Rao, N.B.S.; Shirlal, K.G.2003Item A laboratory investigation on a single row of suspended porous pipes was conducted in a two-dimensional regular wave flume to study their hydraulic performance. The wave energy losses at the structure were computed and the effects of depth of submergence, incident wave steepness, water depth, pipe diameter, percentage of perforations, size of perforations and relative wave height on loss coefficient were studied. It was found that as incident wave steepness increases, loss coefficient K 1 increases. Water depth has insignificant effect on K 1. It is also observed that as percentage of perforations increases, K 1 increases. For the range of variables studied, as the relative wave height increases, K 1 decreases.(Energy dissipation at single row of suspended perforated pipe breakwaters) Rao, S.; Rao, N.B.S.; Shirlal, K.G.; Guddeti, G.R.2003Item A laboratory investigation on perforated hollow piles in two rows was conducted in a two dimensional regular wave flume to study the wave transmission and reflection characteristics. The influence of incident wave steepness, relative clear spacing between the piles and rows of piles on transmission co-efficient and reflection co-efficient have been investigated. The effect of staggering of piles in the rows on both transmission and reflection co-efficients was also studied. The present study has revealed that for perforated pile groups incident wave steepness, relative clear spacing between the piles, relative clear spacing between the rows of piles influence both transmission and reflection co-efficients. Staggering of piles reduces reflection from the perforated piles. Perforated piles have smaller transmission and reflection co-efficient values compared to that of non-perforated piles at lower wave steepness.(Wave transmission and reflection for two rows of perforated hollow piles) Rao, S.; Shirlal, K.G.; Rao, N.B.S.2002Item A laboratory investigation on single row suspended porous pipes was conducted in a two-dimensional regular wave flume to study their hydraulic performance. The effects of porosity, water depth, incident wave steepness and relative wave height on transmission and reflection coefficients were studied. It was found that (a) as incident wave steepness increases transmission coefficient Kt decreases and reflection coefficient Kt increases; (b) water depth has insignificant effect on Kt and Kt for porous pipes; (c) as porosity decreases Kt decreases and Kt increases; and (d) the range of variables studied, as the relative wave height increases Kt increases and Kr decreases.(Performance of single row of suspended porous pipe breakwater) Rao, S.; Rao, N.B.S.; Reddy, Y.V.B.2001Item A laboratory investigation on the suspended perforated hollow cylinders in a single row was conducted in a two-dimensional wave flume, to study their hydraulic performance. The influence of depth of submergence, size of pipes, percentage of perforations and water depth on wave reflection characteristics have been investigated. From the investigation it was found that, as the relative depth of submergence increases, reflection increases. Water depth has insignificant effect on reflection coefficient Kr. The reflection coefficient Kr increases as incident wave steepness increases. For perforated pipes, size of the pipe has negligible effect on Kr. Wave period alone does not directly influence the reflection. © 1999 Taylor & Francis Group, LLC.(Laboratory investigation on wave reflection characteristics of suspended perforated pipe breakwater) Rao, S.; Rao, N.B.S.1999Item Energy dissipation at single row of suspended perforated pipe breakwaters(2003) Rao, S.; Rao, N.B.S.; Shirlal, K.G.; Reddy, G.R.A laboratory investigation on a single row of suspended porous pipes was conducted in a two-dimensional regular wave flume to study their hydraulic performance. The wave energy losses at the structure were computed and the effects of depth of submergence, incident wave steepness, water depth, pipe diameter, percentage of perforations, size of perforations and relative wave height on loss coefficient were studied. It was found that as incident wave steepness increases, loss coefficient K 1 increases. Water depth has insignificant effect on K 1. It is also observed that as percentage of perforations increases, K 1 increases. For the range of variables studied, as the relative wave height increases, K 1 decreases.Item Energy dissipation in suspended porous pipe breakwaters in laboratory(2003) Rao, S.; Rao, N.B.S.; Shirlal, K.G.A laboratory investigation on a single row of suspended porous pipes is conducted in a two-dimensional wave flume to study their hydraulic performance under regular wave attack. The wave energy losses are computed and the effects of porosity, water depth, incident wave steepness and relative wave height on loss coefficient are studied. It is found that loss coefficient increases with an increase in incident wave steepness. Water depth has insignificant effect on K1 when wave steepness is varied. It is also observed that as porosity increases K1 decreases. For the range of variables studied, as the relative wave height increases, K1 decreases.Item In order to study sediment travelling paths across shoreline in different seasons, sediment samples were collected normal to the shoreline along three profiles, separated by 220m from Surathkal beach near Karnataka Regional Engineering College (K.R.E.C.), Karnataka. The sediments were analysed for their grain size characteristics (statistical parameters) and sediment trend matrix was prepared. By using sediment trend matrix, sediment travelling paths were drawn. It has been found that during premonsoon, sediments were moving predominantly towards offshore region, resulting in erosion. Sediments were moving predominantly towards shore and build-up of beach takes place during the post monsoon season.(Sediment trend matrix analysis along shore normal transects off Surathkal beach, Karnataka) Rao, S.; Shirlal, K.G.; Rao, N.B.S.2003Item Laboratory investigation on perforated hollow piles in a single row was conducted in a two dimensional regular wave flume to study the performance of such an arrangement in dissipating wave energy. The influence of spacing between the piles, size of perforations, different percentage of perforations and water depth on wave attenuation has been investigated. It is found that water depth has insignificant effect on transmission coefficient (K(t)) at higher wave steepness. K(t) decreases as the relative clear spacing of piles (b/D) decreases and also it decreases as the incident wave steepness increases. At lower value of b/D, K(t) decreases with increase in percentage of perforations. For the same percentage of perforations, the pile groups with larger size of perforations transmit more wave energy than pile groups with smaller size of perforations. The perforated hollow pile breakwater is an alternative solution to protect the coast from erosion where the erosion is due to wave energy concentration or onshore offshore movement of sand.(Wave attenuation characteristics of single row of perforated hollow piles in laboratory) Subba Rao; Rao, N.B.S.; Prasad, J.S.1999Item Laboratory investigation on wave reflection characteristics of suspended perforated pipe breakwater(1999) Rao, S.; Rao, N.B.S.A laboratory investigation on the suspended perforated hollow cylinders in a single row was conducted in a two-dimensional wave flume, to study their hydraulic performance. The influence of depth of submergence, size of pipes, percentage of perforations and water depth on wave reflection characteristics have been investigated. From the investigation it was found that, as the relative depth of submergence increases, reflection increases. Water depth has insignificant effect on reflection coefficient Kr. The reflection coefficient Kr increases as incident wave steepness increases. For perforated pipes, size of the pipe has negligible effect on Kr. Wave period alone does not directly influence the reflection. 1999 Taylor & Francis Group, LLC.Item Laboratory investigation on wave transmission through suspended perforated pipes(2001) Rao, S.; Rao, N.B.S.An experimental investigation on the hydraulic performance of suspended perforated hollow cylinders in a single row with a relative clear spacing of 0.15 between pipes was conducted in a two- dimensional wave flume. The influence of relative depth of submergence, incident wave steepness, size of pipes, size of perforations, percentage of perforations and water depth on wave attenuation has been investigated. From the investigation it was found that, as the depth of submergence increases transmission coefficient decreases. But beyond 50% of depth of submergence decrease in transmission is negligible. Transmission decreases as incident wave steepness increases. Forperforated pipes, size of the pipe has marginal effect on transmitted wave characteristics for the relative clear spacing considered. Perforated pipes with 25% of perforations are found to attenuate about 10% to 14% more wave energy than non-perforated pipes. Size of perforations does not have much effect on transmission for the same area of perforations. 2001 Taylor & Francis Group, LLC.Item Laboratory investigation on wave transmission through two rows of perforated hollow piles(1999) Rao, S.; Rao, N.B.S.; Sathyanarayana, V.S.Experimental investigations on perforated hollow piles in two rows were conducted in a two dimensional wave flume. The influence of water depth, incident wave steepness, clear spacing between the piles and the spacing of pile rows on transmission coefficient have been studied. The effect of staggering of piles in rows is investigated. The results are also compared with the results of experiments on piles without perforations. The investigations have revealed that perforated piles attenuate more wave energy than non-perforated piles. The transmission coefficient K(t) decreases as the wave steepness increases for both non-perforated and perforated piles. For non-perforated piles as relative clear spacing between the piles (b/D) decreases, for waves of higher steepness, K(t) decreases while for perforated piles as b/D decreases, K(t) is decreasing for all the steepness considered. As the relative clear spacing between the pile rows (B/D) increases K(t) initially decreases till B/D is around one and later it starts increasing for both non-perforated and perforated piles. Staggering of piles has little effect on K(t). It is also found that water depth has insignificant influence on transmission coefficient at higher steepness for both perforated and non-perforated piles. Wave period alone does not directly influence transmission coefficient K(t).Experimental investigations on perforated hollow piles in two rows were conducted in a two dimensional wave flume. The influence of water depth, incident wave steepness, clear spacing between the piles and the spacing of pile rows on transmission coefficient have been studied. The effect of staggering of piles in rows is investigated. The results are also compared with the results of experiments on piles without perforations. The investigations have revealed that perforated piles attenuate more wave energy than non-perforated piles. The transmission coefficient Kt decreases as the wave steepness increases for both non-perforated and perforated piles. For non-perforated piles as relative clear spacing between the piles (b/D) decreases, for waves of higher steepness, Kt decreases while for perforated piles as b/D decreases, Kt is decreasing for all the steepness considered. As the relative clear spacing between the pile rows (B/D) increases Kt initially decreases till B/D is around one and later it starts increasing for both non-perforated and perforated piles. Staggering of piles has little effect on Kt. It is also found that water depth has insignificant influence on transmission coefficient at higher steepness for both perforated and non-perforated piles. Wave period alone does not directly influence transmission coefficient Kt.Item Performance of single row of suspended porous pipe breakwater(2001) Rao, S.; Rao, N.B.S.; Reddy, Y.V.B.A laboratory investigation on single row suspended porous pipes was conducted in a two-dimensional regular wave flume to study their hydraulic performance. The effects of porosity, water depth, incident wave steepness and relative wave height on transmission and reflection coefficients were studied. It was found that (a) as incident wave steepness increases transmission coefficient Kt decreases and reflection coefficient Kt increases; (b) water depth has insignificant effect on Kt and Kt for porous pipes; (c) as porosity decreases Kt decreases and Kt increases; and (d) the range of variables studied, as the relative wave height increases Kt increases and Kr decreases.Item Sediment trend matrix analysis along shore normal transects off Surathkal beach, Karnataka(2003) Rao, S.; Shirlal, K.G.; Rao, N.B.S.In order to study sediment travelling paths across shoreline in different seasons, sediment samples were collected normal to the shoreline along three profiles, separated by 220m from Surathkal beach near Karnataka Regional Engineering College (K.R.E.C.), Karnataka. The sediments were analysed for their grain size characteristics (statistical parameters) and sediment trend matrix was prepared. By using sediment trend matrix, sediment travelling paths were drawn. It has been found that during premonsoon, sediments were moving predominantly towards offshore region, resulting in erosion. Sediments were moving predominantly towards shore and build-up of beach takes place during the post monsoon season.Item Wave attenuation characteristics of single row of perforated hollow piles in laboratory(1999) Subba, Rao; Rao, N.B.S.; Prasad, J.S.Laboratory investigation on perforated hollow piles in a single row was conducted in a two dimensional regular wave flume to study the performance of such an arrangement in dissipating wave energy. The influence of spacing between the piles, size of perforations, different percentage of perforations and water depth on wave attenuation has been investigated. It is found that water depth has insignificant effect on transmission coefficient (K(t)) at higher wave steepness. K(t) decreases as the relative clear spacing of piles (b/D) decreases and also it decreases as the incident wave steepness increases. At lower value of b/D, K(t) decreases with increase in percentage of perforations. For the same percentage of perforations, the pile groups with larger size of perforations transmit more wave energy than pile groups with smaller size of perforations. The perforated hollow pile breakwater is an alternative solution to protect the coast from erosion where the erosion is due to wave energy concentration or onshore offshore movement of sand.Item Wave transmission and reflection for two rows of perforated hollow piles(2002) Rao, S.; Shirlal, K.G.; Rao, N.B.S.A laboratory investigation on perforated hollow piles in two rows was conducted in a two dimensional regular wave flume to study the wave transmission and reflection characteristics. The influence of incident wave steepness, relative clear spacing between the piles and rows of piles on transmission co-efficient and reflection co-efficient have been investigated. The effect of staggering of piles in the rows on both transmission and reflection co-efficients was also studied. The present study has revealed that for perforated pile groups incident wave steepness, relative clear spacing between the piles, relative clear spacing between the rows of piles influence both transmission and reflection co-efficients. Staggering of piles reduces reflection from the perforated piles. Perforated piles have smaller transmission and reflection co-efficient values compared to that of non-perforated piles at lower wave steepness.