Kaushik Sasmal

Kaushik Sasmal
Technology Centre for Offshore and Marine, Singapore (TCOMS)

PhD

About

33
Publications
3,164
Reads
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150
Citations
Additional affiliations
November 2016 - October 2020
The University of Tokyo
Position
  • Researcher
November 2014 - March 2016
Education
January 2009 - July 2014
Indian Institute of Technology Kharagpur
Field of study
  • Physical Oceanography

Publications

Publications (33)
Article
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...
Article
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,...
Article
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...
Article
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...
Article
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...
Article
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...
Conference Paper
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...
Conference Paper
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...
Conference Paper
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...
Article
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...
Article
Full-text available
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...
Article
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...
Article
Full-text available
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...
Preprint
Full-text available
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...
Article
Full-text available
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...
Article
Full-text available
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...
Article
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...
Article
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...
Article
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...
Article
Full-text available
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...
Conference Paper
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...
Conference Paper
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...
Article
Full-text available
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...
Conference Paper
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...
Conference Paper
Full-text available
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...
Conference Paper
Full-text available
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...
Conference Paper
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...
Conference Paper
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...
Conference Paper
Full-text available
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...

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