K. Murali

Bio: K. Murali is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Breakwater & Finite element method. The author has an hindex of 14, co-authored 73 publications receiving 700 citations. Previous affiliations of K. Murali include Swansea University & Institute of High Performance Computing Singapore.

Numerical Simulation of Wave Interaction with Submerged Porous Structures and Application for Coastal Resilience

Abstract: Srineash, VK; Kamath, A; Murali, K, and Bihs, H, 2020 Numerical simulation of wave interaction with submerged porous structures and application for coastal resilience Journal of Coastal Research, 36(4), 752–770 Coconut Creek (Florida), ISSN 0749-0208The study of wave interaction with porous structures is essential as coastal structures are often porous in nature because of their prominent energy dissipation characteristics The present work is focused on the numerical modeling of wave interaction with submerged porous structures, which are often classified as reef breakwaters and low-crested structures Numerical modeling of wave interaction with porous structures is considered to be a challenge for researchers because of the complexities associated with it The present study numerically investigates the wave interaction process through the porous media by representing the porous media using Volume-averaged Reynolds-Averaged Navier–Stokes (VRANS) equations For the study, an open-source RANS-based computational fluid dynamics tool, REEF3D, has been used for numerical modeling The study also consists of experiments that are used for validating the numerical model The numerical results for the free-surface elevation and the hydrodynamic pressure are compared with the experimental measurements and found to be in good agreement The numerical study is extended to different crest widths of the structure and varying wave parameters to investigate the effects of various dimensionless parameters affecting wave transmission The frequency-domain analysis is performed to investigate the energy distribution of the incident and transmitted waves Finally, the utility of the numerical model adopting VRANS equations has been demonstrated for climate-change mitigation studies This has been carried out by studying the effects of pressure reduction on a vertical seawall due to the presence of a porous reef breakwater in the sea side Pressure reduction up to 32% is calculated because of the presence of the porous structure in front of the seawall and this demonstrates the application of reef breakwaters for coastal resilience studies Such investigations are useful in protecting the existing coastal structures prone to severe wave conditions exceeding the design limits

Effect of the Tidal Currents at the Amphidromes on the Characteristics of an N-Wave-Type Tsunami

Abstract: The disturbance due to a tsunami is always coupled with permanent harmonic ocean tides. The tsunami based on its time of occurrence will combine with a particular tidal phase. Thus, a coast will experience a modified water level due to a high- or low-tide situation. On the other hand, the tidal current at the amphidromes may act as an attenuator or amplifier of the tsunami prior to its arrival at the shore. A one-dimensional numerical study has been carried out to demonstrate the effect of the amphidromic current on tsunami characteristics. A realistic N-wave profile of the initial perturbation has been considered for the initiation of a tsunami. The interaction of the amphidromic current with the phase velocity of an N-wave-type tsunami and the subsequent run-up along the shore has been investigated in this paper.

A comparative study of dynamic mesh updating methods used in the simulation of fluid-structure interaction problems with a non-linear free surface

Abstract: This paper compares the performance of three mesh movement algorithms: Laplacian smoothing, linear spring analogy and torsion spring analogy for a fluid mesh update in staggered fluid-structure interaction (FSI) simulations with a non-linear free surface. The mesh updating schemes are applied to simulate three representative cases of the above-stated dual moving boundary problem. The performances of the algorithms are gauged on the basis of their ability to delay the initiation of a complete remesh of the fluid domain while maintaining solution accuracy. To satisfy this dual objective, the mesh-updating algorithm should not only prevent mesh failure but should also maintain well-shaped triangles. The reasons for the failure of different schemes are explained and suitable modifications are suggested/implemented to enhance thier performance. It is shown that these modifications prove to be very successful in improving the effectiveness of the algorithms.

Sri Lanka Field Survey after the December 2004 Indian Ocean Tsunami

Abstract: In August 2005, a team surveyed the effects of the December 2004 Indian Ocean tsunami on the southern coast of Oman. Runup and inundation were obtained at 41 sites, extending over a total of 750 km of shoreline. Measured runup ranged from 3.25 m in the vicinity of Salalah to a negligible value at one location on Masirah Island. In general, the largest values were found in the western part of the surveyed area. Significant incidents were documented in the port of Salalah, where a 285-m-long vessel broke its moorings and drifted inside and outside the port, and another ship struck the breakwater while attempting to enter the harbor. The general hazard to Oman from tsunamis may be greatest from the neighboring Makran subduction zone in western Pakistan.