Browsing by Author "Pavan Kumar, G. V. V."

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Assessing underwater noise levels during various port activities at the Visakhapatnam channel
(Indian Maritime University, Visakhapatnam, 2019) Pavan Kumar, G. V. V.; Prasanna Kumar, A.; Prasad, V. V. S.
Transport infrastructure is one of the most important factors for country’s progress or economic growth. Ports serve as important transportation hubs that facilitate goods movement. Visakhapatnam Port is the second largest port by volume of cargo handled located in the east coast of India. Under the modernization program the port is capable for handling vessels up to 14.5 m by maintenance dredging and some jetties extension with piling activity. The major activities of the port operation are the vessel handling using tugs and movement of other vessel within the inner harbor of the Visakhapatnam channel. The underwater noise levels of the channel are measured by deploying Omni-directional hydrophone at different location along the channel and the radiated noise levels due to the tug boat operations. The TASCAM data recorder is used to convert the voltage signal to sound file and Fast Fourier Transformation spectral analysis program for post-processing the time and frequency domain spectrum. The tug machinery self-noise indicated a peak amplitude of 157 dB re 1μ Pa at 425 Hz. The jetty modification work recorded the piling activity radiated noise levels as indicated in the spectrogram in the lower frequency of nearly one second duration. The anthropogenic noise due to tugs movement and the piling activity have major influence in increasing the ambient noise of the region. However, there are no evidence of presence any marine mammals getting effected due to the continuous shipping and other activities in the region. The present study shall help to develop measures to reduce the increase in the ambient noise levels of the region due to various anthropogenic sources as part of a major environment impact assessment study for developing a green port.
Development of autonomous dredger for inland waterways and enclosed water bodies
(EADA(I) Silver Jubilee Seminar, 2018-03-15) Pavan Kumar, G. V. V.; Ramesh, U. S.; Sivakholundu, K. M.
The conceptual layout of the proposed autonomous dredger is presented. The potential for dredging in inland water bodies - reservoirs and inland waterways – in India is five times larger than the conventional dredging (ports and channels). Unlike arine dredgers, these small dredgers cannot be directly scaled up due to restrictions imposed by transportation, environmental conditions, draft and deployment. To overcome some of the difficulties, Indian Maritime University at Visakhapatnam campus IMU[V] is working on the development of an Autonomous Dredger (AD). The design philosophy revolves around modularity, ase of transport and autonomous operation. Modularity will ensure that the dredger can be dismantled for road transport and assembled at dredge site with minimal handling machinery. AD is being designed for calm water operations with four point mooring support and meant for clay and sand removal by water jet based dredging. The autonomous operation will ensure unattended dredging operation on 24x7 basis. The AD will have an in-built bathymetric survey system that will provide pre and post dredging quantification. While deployment the overall reservoir site will be divided into small ‘cell’ of convenient size (say 100 x 100m). After deployment, the AD will survey, dredge and verify the work done autonomously within the cell. Manual intervention for operational purpose will be kept to a minimum for shifting the AD from one cell to next.
Identification of design drivers for ship radiated underwater noise and the airborne noise levels on tugs
(International Journal of Innovation Research & Development, 2015-07) Pavan Kumar, G. V. V.; Sasmita, P.
The most widespread and pervasive kind of anthropogenic energy is underwater sound. Shipping noise is a major contributor to the ambient noise levels of the oceans and a major source for adverse effects on marine mammals. Proper design considerations need to be studied on noise sources on ships to reduce airborne and underwater noise levels and improve safety. There is a need to identify the various noise sources (propeller, machinery and flow around ship) on ship and check alternatives means to dampen each noise source propagations, so has to have considerable damping in overall airborne and underwater noise levels in the initial design stages. Measurements of airborne noise have been carried out in various location of different propulsion type tugs in the channel of Visakhapatnam and a comparison of the results is tabulated. The measurements of the airborne noise levels on five tugs are noted during regular towing operation. The noise levels in the Engine room are well below the permissible limits but in other locations the noise levels are above the limits. The reason for the noise limits to be above the acceptable limits in upper deck regions being the position of the ventilation blower unit in the above deck and the windows in open condition during measurements. Also the average noise levels of Voith Schneider propulsion (VSP) and Schottel Rudder propulsion (SRP) is 103 dB. The vessel traffic noise levels at the entrance of the channel is around 69 dB. The most widespread and pervasive kind of anthropogenic energy is underwater sound. Shipping noise is a major contributor to the ambient noise levels of the oceans and a major source for adverse effects on marine mammals. Proper design considerations need to be studied on noise sources on ships to reduce airborne and underwater noise levels and improve safety. There is a need to identify the various noise sources (propeller, machinery and flow around ship) on ship and check alternatives means to dampen each noise source propagations, so has to have considerable damping in overall airborne and underwater noise levels in the initial design stages. Measurements of airborne noise have been carried out in various location of different propulsion type tugs in the channel of Visakhapatnam and a comparison of the results is tabulated. The measurements of the airborne noise levels on five tugs are noted during regular towing operation. The noise levels in the Engine room are well below the permissible limits but in other locations the noise levels are above the limits. The reason for the noise limits to be above the acceptable limits in upper deck regions being the position of the ventilation blower unit in the above deck and the windows in open condition during measurements. Also the average noise levels of Voith Schneider propulsion (VSP) and Schottel Rudder propulsion (SRP) is 103 dB. The vessel traffic noise levels at the entrance of the channel is around 69 dB.
Motion characteristics of a research vessel for short-term voyage
(Indian Maritime University, Visakhapatnam, 2019) SaiKiran, Lekkalaa.; Pradhyumna, S. K.; Pavan Kumar, G. V. V.; Nagesh, Bh.
All floating bodies are subjected to 6 degree of freedom due to various encountering forces. The design challenge lies in reducing the excessive ship behaviour and design a comfort class ships. Research vessel in specific to be design to best comfort since they can have used by non-seafarers. This paper shows the study on motion characteristics of the vessel where the real- time data measured from the newly built coastal research vessel. The data is obtained from the ships Motion Response Unit for the entire duration of the voyage which is approx. 6 hr. 30 mins. The results obtained indicate a peak roll amplitude of 12.03 Degree and average of 6.0 degree. The peakheave motion obtained 1.8m, pitch of 4.39 degree, surge of 3.9 and, sway of 7.6m.The results obtained indicate that the vessel behaved in a normal condition within the acceptable criteria in the sea state 3 which favourable for carrying out scientific activities. The dampening devices like the bilge keel, Anti-roll tank and other devices helped in improving the vessel performance.