Kaushik SasmalTechnology Centre for Offshore and Marine, Singapore (TCOMS)
Kaushik Sasmal
PhD
About
33
Publications
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150
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Introduction
Additional affiliations
November 2016 - October 2020
November 2014 - March 2016
Education
January 2009 - July 2014
Publications
Publications (33)
The ocean waves in the North Atlantic Ocean are internationally recognized to represent a wave climate suitable for the design of merchant ships. However, the accumulated knowledge from the past indicates that the encountered sea states are less severe than the Standard Wave Data recommended by the International Association of Classification Societ...
At reconnaissance to feasibility study stages of wave energy development, guidelines and standards recommend wave power assessments to be conducted for long periods of time, albeit at relatively coarse spatial resolutions. However, quite often developers need to make a preliminary site selection based on high-resolution information. Unfortunately,...
The three-dimensional numerical model SUNTANS is applied to investigate river plume mixing in Otsuchi Bay, an estuary located along the Sanriku Coast of Iwate, Japan. Results from numerical simulations with different idealized forcing scenarios (barotropic tide, baroclinic tide, and diurnal wind) are compared with field observations to diagnose dom...
The present paper explores the derivation of an alternative nonlinear eddy viscosity formulation based on Reynolds stress anisotropy and its implementation to numerical
ocean models. This formulation takes into account the vorticity in addition to the
mean strain rate. The proposed formulation does not include the stability function
method which is...
In the coming decades, the global maritime industry will face a most formidable technological and societal challenge set by climate change – achieving net zero carbon emissions by 2050. To meet this target, ships are shifting towards the use of low-carbon alternative fuels such as ammonia and methanol. While this paradigm shift to the bunkering of...
Fuel-saving potential by optimizing speed as well as route has been studied in a wide variety of operating conditions on a trans-Pacific route. Analysis using different seasonal weather patterns and various ship speeds allows a more robust estimation of possible fuel savings. Up to 18% reduction in fuel consumption was observed on eastbound voyages...
Operational forecasts of wind waves are crucial for various practical applications in nearshore and offshore areas. Wave fields such as wave height, wave period and wave directions are used for the speed and voyage optimization of ships. High-resolution information of wind waves is often required for the planning of operations within the ports. Usi...
The statistics of the waves in the North Atlantic Ocean have been used as the basis of ship design for decades. Recently, there have been efforts to update the scatter diagram of wave height and period based on the numerical hindcast data combined with AIS data. However, the validation of the extreme wave distribution is problematic due to the lack...
As the first recorded TC formation within 1.5 degrees of the equator, TC Vamei developed in the equatorial region on 27 December 2001 with diminishing Coriolis effect. Satellite-derived wave height exhibits high sea states during the passage of TC Vamei. In the present study, numerical experiments using the third-generation wave models, WAVEWATCH I...
Potential fuel savings using a speed optimization algorithm have been studied for two case vessels in four different seasons at three ship speeds. Up to 6% fuel savings were observed. It was found that the savings are higher in seasons with a higher likelihood of severe weather conditions. Larger savings were observed at lower ship speeds which mea...
Accurate knowledge of ocean surface waves is crucial for ship design. With the significant advancements in model physics and numerical resources, recent numerical wave hindcast data has the potential to provide environmental conditions for estimating the wave load in the ship design process. To help estimate extreme wave loads with quantified uncer...
Ships avoid severe sea states for the safety of lives and property and to save energy. Therefore, the actual sea states encountered by ships differ from nature and are affected by human operational effects that we refer to as the “ship operational effect”. The evaluation of the ship operational effect is crucial for the rational design of structura...
A numerical wave model has been set up and tuned for the Singapore region extending to the parts of the South-China Sea and Malacca Strait. The MIKE 21 spectral wave model was set up using ERA5/ECMWF wind and waves reanalysis data to compute the phase-averaged significant wave heights. The outputs of the calibrated model validates well with the ECM...
Accurate ocean surface wave knowledge is crucial for ship design. With the significant advancements of model physics and numerical resources, the recent numerical wave hindcast data has a potential to provide environmental conditions for wave load estimation in the ship design process. This study aims to quantify model uncertainty in the state of a...
The sea ice coverage in the summer Arctic Ocean from the Beaufort to Laptev Seas continues to decrease, and the largest waves in the western Arctic open waters are increasing year by year. By looking into the historical wave events in the ERA-Interim reanalysis data, we discovered that more than half of the extreme events are caused by cyclones tha...
Eddy viscosity models in turbulence modeling can be mainly classified as linear and nonlinear models. Linear formulations are simple and require less computational resources but have the disadvantage that, those can't predict actual flow pattern in complex geophysical flows where streamline curvature and swirling motion are predominant. A constitut...
High riverine freshwater discharge makes the salinity distribution highly heterogeneous in the Bay of Bengal (BoB). This paper investigates the impact of freshwater discharge from ten major rivers on the seasonal sea surface variability and the coastal Kelvin wave characteristics in the BoB using the Regional Ocean Modeling System (ROMS). Two numer...
In this paper, we consider the evolution of decaying homogeneous anisotropic turbulence
without mean velocity gradients, where only the slow pressure rate of strain is non zero. A
higher degree nonlinear return- to - isotropy model has been developed for the slow pressure strain
correlation, considering anisotropies in Reynolds stress, dissipation...
The present work explores the applicability of an alternative eddy viscosity formulation in numerical models dealing with the dynamics of the coastal ocean. The formulation is based on the Reynolds stress anisotropy–anisotropy being an important tool for capturing turbulent mixing. Initially idealized entrainment scenarios are evaluated that are ty...
The air–sea interaction process and its implication at the outfall location of a nuclear power plant have been studied using the Princeton ocean model (POM) under varied environmental forcing parameters (momentum and heat fluxes). In the first set of numerical experiments, constant momentum flux is used with reversing wind speeds of 2 and 10 ms −1...
The state-of-the-art numerical ocean models like the Princeton Ocean Model (POM) solves
for turbulence by solving the eddy viscosity through two equation models of Mellor and
Yamada (1982) or Canuto et al. (2001). They use stability function based method to
determine the turbulent viscosity. This involves computation of complex forms of stability
f...
Two different eddy viscosity formulae, developed for different engineering flow applications, have been
transformed for geophysical flows taking into account the second invariant of Reynolds stress anisotropy. These obviate the computations of the conventional stability functions for predicting eddy viscosity values with the help of state-of-the-a...
An improved model for the slow pressure strain of turbulence is developed. Reynolds stress models are routinely used in CFD modeling recently with the improvement of computer resources. The most widely used Reynolds stress model is the SSG (Speziale, Sarkar, Gatski) model. Our formulation is a mathematical addition/variation to that model. The util...
Study of dispersion of plume associated with nuclear reactors is of utmost importance in an urban environment especially near the coastal belt where millions of people live. In the present study an automated Coupled Atmosphere-Ocean Model (CAOM) that has been developed is used for predicting ocean states such as sea surface temperature and sea surf...
The present study is an attempt to examine the affect of different initial boundary conditions (NCEP FNL, GFS) on the regional numerical models (AWRF, WRF-3D Var) for the Thane cyclone initiated on 25 December, 2011 in the Bay of Bengal (BoB). Sensitivity experiments are made to observe track prediction, inten-sity and land fall positions of the cy...
The air-sea interaction process and its implication to an outfall location emanating from a nuclear power plant are investigated in the present study. The state-of-art numerical model POM under varied forcing parameters was investigated to understand the effect of atmospheric forcing on the resultant dispersion trajectories. The numerical experimen...
Eddy viscosity in turbulence is determined with the help of stability functions in three
dimensional state-of-art hydrodynamic numerical ocean models like POM. These stability functions
are functions of the shear number and the buoyancy number and are complex in nature. Moreover
these models take into consideration the fact that the return to is...
The present study reports on the dispersion of thermal plume from the outfall region of the Kalpakkam by using an automated flux coupling mechanism in a Coupled Atmosphere-Ocean Model (CAOM). This flux coupler have direct significance for ocean state forecast studies such as prediction of sea-surface temperature (SST), surface circulation etc. The...
The present study reports on the development of an automated atmosphere-ocean coupling system to enhance the understanding of oceanic processes. The coupled system has the capability to simulate features such as ocean surface circulation, sea-surface temperature (SST) in a real-time mode. To accomplish this task, two state-of-art models viz; Weathe...