Browsing by Author "Mallampalli, Premchand"

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Numerical study on maneuvering a container ship in shallow water waves
(International Journal of Innovative Research and Scientific Studies, 2023) Mallampalli, Premchand; Janardhanan, Sheeja; Karottu, Kesavadev Varikattu; Ommi, G.
Numerous practical and mathematical techniques have been piloted to study ships’ behavior in deep water conditions with and without waves, and shallow water conditions without waves, while only limited investigations have been carried out to assess ships’ behavior in shallow waters with wave conditions as the flow around the stern region and appendages and the interaction effects are intricate. Therefore, this study attempts to understand the infrequently explored subset of a vessel’s behavior in regular waves in shallow water conditions (channel depth to ship draft ratio taken as 1.5). A container ship (S175) model scaled at 1:36 was the subject of a numerical study in which it was subjected to static and dynamic maneuver simulations in head sea conditions. The waves were induced using the dispersion relationship of waves in a given depth. The trends of forces and moments acting on the hull while undergoing maneuvering motions were obtained using a smooth particle hydrodynamics-based computational fluid dynamics solver. The resulting periodic trends of forces and moments were analyzed using the Fourier series method to extract the Fourier coefficients and, in turn, calculate the hydrodynamic derivatives. The trajectories in turning circle and zigzag maneuvers were also simulated using a MATLAB code. The results demonstrate an increase in trajectory parameters and improvement in counter maneuverability owing to the complex flow physics around the hull when encountering regular waves in shallow water conditions compared to waves in deep waters and a lack of waves in shallow waters.
Numerical study on maneuvering a container ship in shallow water waves /
(IJIRSS, 2023-09-15) Mallampalli, Premchand; Janardhanan, Sheeja; Karottu, KesavadevVarikattu; Ommi, Gnaneswar
Numerous practical and mathematical techniques have been piloted to study ships’ behavior in deep water conditions with and without waves, and shallow water conditions without waves, while only limited investigations have been carried out to assess ships’ behavior in shallow waters with wave conditions as the flow around the stern regionandappendages and the interaction effects are intricate. Therefore, this study attemptsto understand the infrequently explored subset of a vessel’s behavior in regular waves in shallow water conditions(channel depth to ship draft ratio taken as 1.5). A container ship (S175) model scaledat 1:36 was the subject of a numerical study inwhich it was subjected to static and dynamic maneuver simulations in head sea conditions. The waves were induced using the dispersion relationship of waves in a given depth. The trends of forces and moments acting on the hull while undergoing maneuvering motions were obtained using a smooth particle hydrodynamics-based computational fluid dynamics solver. The resulting periodic trends of forces and moments were analyzed using the Fourier series method to extract the Fourier coefficients and,in turn,calculate the hydrodynamic derivatives. The trajectories in turning circle and zigzagmaneuverswere also simulated using a MATLAB code. The results demonstrate an increase in trajectory parameters and improvement in counter maneuverability owing to the complex flow physics around the hull whenencountering regular waves in shallow water conditionscompared to waves in deep watersand a lack of waves in shallow waters.
Safety aspects related to passenger transportation in NW-1
(2015-02) Mallampalli, Premchand; Kalyani, T.
Study on different concepts for design of a coastal research vessel
(IIT, Kharagpur, 2011-12) Mallampalli, Premchand
The design of any vessel is a series of compromises which trade off one property for another. Catamarans are particularly appropriate in the size range from 45 to 170 feet, where they offer many of the advantages of considerably longer conventional vessels in a shorter, wider, shallower draft, fuel efficient package. Designing and using modern catamarans is lot like designing and using aircraft where strength/weight considerations are crucial. Weight control is essential for good and safe performance offshore. Blind application of monohull design ideas has lead to the creation of a number of needlessly heavy (and thus expensive) catamarans with poor sea keeping. Fuel load takes the place of science cargo as the primary weight to be hauled, which in turn requires larger engines to achieve the design speed and range, which requires more fuel and so on. The design spiral then diverges from well-proven wholesome, catamaran design practice. This paper signifies the importance of catamaran hull form benefits as a research vessel and the reasons for selecting this hull form. Study is also done on the spacing between the two hulls with symmetrical demihull and asymmetrical demihull. Resistance, working deck space, operating cost options are the primary factors in determining catamaran hull form as the most efficient out of the comparison between monohull and catamaran. This paper signifies the effect of bulbous bow [9] in reducing the resistance components and increasing the volume of displacement for a given set of constraints.