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.

Role of vegetation on beach run-up due to regular and cnoidal waves.

Abstract: The effectiveness of measures in protecting the coast against natural hazards depends on the extent of run-up by ocean waves, which is an essential parameter in their planning and design. Although, several formulae have been derived in the past for estimation of run-up in laboratory studies for a variety of wave front structures, certain uncertainties still remain pertaining to flat slopes and long waves. To understand the performance characteristics of vegetation in attenuating run-up, a comprehensive experimental investigation was taken up. The studies were carried out with regular and cnoidal waves propagating over a plane slope of 1 ∶ 30 in the presence and absence of vegetation of different characteristics. The results on the variation of dimensionless run-up as a function of wave and vegetal parameters are presented and discussed in this paper.

Estimation of hull-propeller interaction of a self-propelling model hull using a RANSE solver

Abstract: Viscous flow around the self-propelled hull was investigated at model scale with a RANSE solver using k-ϵ turbulence model by coupling the flow around the hull model with the flow generated by the rotating propeller. Hence, the challenges involved in the coupling of flow past ship hull with propeller flow of lower-order scale have been brought out and addressed here. Propeller rotation is accounted for by mesh motion; the solution domain is represented by a rotating cylindrical domain encompassing the propeller and a fixed rectangular domain around the hull for the remaining part of the solution domain; both these domains are interfaced by sliding interfaces. Comparisons are made between the simulated results and corresponding experimental results for hull resistance, propeller thrust and propeller RPM. It is shown that the flow field in the self-propelling condition is well reproduced in the simulation, and the estimated thrust deduction factor and RPM agree well with the measured ones. Among the various...

An artificial compressibility based fractional step method for solving time dependent incompressible flow equations. Temporal accuracy and similarity with a monolithic method

Abstract: In this note, an artificial compressibility based fractional step method is analysed against a monolithic scheme for solving incompressible flow equations. The artificial compressibility (AC) procedure presented in this paper is stabilized via a characteristic based split (CBS), and thus it is referred to as the AC-CBS method. The monolithic method used for comparison in the present study is the pressure stabilized Petrov–Galerkin (PSPG) method. It is shown that the AC-CBS and PSPG procedures are identical in structure, except for the stabilization parameters. For unsteady problems, a dual time stepping algorithm is employed in the AC-CBS scheme. Unlike classical fractional step methods, this dual time stepping mechanism circumvents the temporal pressure splitting error, and thus provides the anticipated temporal accuracy. The temporal accuracy of the AC-CBS method is demonstrated via a standard benchmark problem. Up to fourth order time accurate schemes are introduced for a thorough analysis of the AC-CBS scheme.

Wave-Induced Pressures and Forces on Deck Slabs near the Free Surface

Abstract: The hydrodynamic interaction of regular and random waves with a model offshore deck has been investigated in a wave flume. The hydrodynamic pressures and forces on the model as well as its reflection and transmission characteristics are investigated in a dimensionless form. The experiments were carried out for three different clearances (e) between the still water level and the subface of the model. In order to investigate the effects of relative clearance of the deck ( e/H in case of regular waves and e/ Hs in case of random waves), different wave steepnesses ( H/L in case of regular waves and Hs / Lp in case of random waves) were employed by varying wave height (H) and wavelength (L) . The effects of the wave steepness, relative clearance of the deck, relative length of the model ( B/L in case of regular waves and B/ Lp in case of random waves) on the pressures and forces on the deck slab are investigated with a well controlled experimental program. The variation of the pressures along the length of the...

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.