Faculty Publications

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    Laboratory investigations of wave attenuation by simulated vegetation of varying densities
    (Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2019) John, B.M.; Shirlal, K.G.; Rao, S.
    Coastal communities across the world are facing the need to adapt to rising sea levels, an increase in the frequency of natural hazards like storm surges, cyclones, tsunamis, and an increase in beach erosion. This present-day scenario calls for a sustainable, environment-friendly, and cost efficient solution for coastal protection. Under these circumstances, the role of vegetation in providing ecosystem services to coastal populations is becoming increasingly prominent. This work presents the results of an experimental study carried out with simulated rigid submerged and emergent vegetation meadows of varying plant densities in a wave flume 50 m long, 0.71 m wide and 1.1 m deep. The material used for modeling the vegetation is nylon. The tests are carried out with regular waves for water depths of 0.40 and 0.45 m, and wave periods 1.4–2 s at an interval of 0.2 s. Five different wave heights ranging from 0.08 to 0.16 m at an interval of 0.02 m are generated. Measurements of wave heights at different locations indicate an exponential decay in wave height along the vegetation meadow which leads to wave attenuation and confirms that vegetation can be a viable option for coastal protection. © 2017, © 2017 Indian Society for Hydraulics.
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    Comprehensive Analysis of Gabion Configurations for Modelling Tsunami-Resilient Rubble Mound Breakwaters
    (Springer, 2025) Sajan, M.K.; Sah, B.; Kumar, S.; Chaudhary, B.
    Coastal communities face significant threats from tsunamis, which cause extensive damage to infrastructure and endanger human lives. Rubble mound breakwaters, widely adopted structures in ports and harbours globally, serve as the first line of defense against tsunami waves. However, their failures in past tsunamis highlight the need for enhanced resilience. The performance of rubble mound breakwaters under tsunami conditions has received limited research attention, and few studies have explored effective countermeasures to mitigate tsunami-induced damages. This study addresses this research gap by performing a comprehensive evaluation through physical model tests, analytical studies and numerical simulations, focusing on the behaviour of rubble mound breakwaters under tsunami overflow. Observations from the responses of conventional models during overflow tests informed the proposal of a reinforcing technique utilizing gabions as a countermeasure to enhance tsunami resilience. Measurements of crest displacements and excess pore water pressure developed in both the foundation soils and the breakwater during tsunami overflow were ascertained to comparatively analyse the performance of the proposed reinforced models. An in-depth analysis was conducted on the placement and positioning of gabions to identify the most effective configuration for transforming a conventional rubble mound breakwater into a tsunami-resilient structure. Among the various gabion placement configurations studied, the stepped configuration demonstrated a remarkable 97.8% reduction in settlement during tsunami overflow. Further analytical and numerical studies were performed to assess the performance of the proposed gabion-reinforced model under tsunami overflow conditions. This proposed technique presents significant potential for protecting a wide range of coastlines by enhancing the resilience of rubble mound breakwaters against tsunamis. © The Author(s), under exclusive licence to Indian Geotechnical Society 2025.