Research

My research interest lies in the field of Ocean, Offshore and Coastal Engineering. Over the past many years, I have been developing state of the art numerical models to tackle the wave-structure interactions. Brief overview are given below, along with the recent development from my research group students.

Semi Arbitary Lagrangian and Eulerian FEM (SALE-FEM/FNPT) IITM-FNPT2D

See details and code release at  http://www.doe.iitm.ac.in/vsriram/fnpt-2d/

This is the computer code to reproduce the experimental wave tank as close as possible using the fully nonlinear potential flow theory developed in Sriram (2008). So far this code has been applied to study:

1. Submerged bar interaction.

2. Submerged cylinder interaction.

3. Sloshing.

4. Kinematics of Solitary waves and its interaction with continental shelf

5. Numerical and Physical speed of the nonlinear waves.

6. Rogue/freak waves.

7. Weak Coupling with ANSYS-CFX for offshore wind energy structure.

8. Hybrid coupling with IMLPG_R.

Results from SALE-FEM

 

 

Wave Elastic Structure Interaction using IMLPG_R (IITM-WESI)

In collaboration with Hydrodynamics research group at City University, an Improved Meshless Local Petrov Galerkin method has been developed. The advantage of this particle method is that it is free from pressure oscillations, so coupling with other solvers and for impact studies are feasible using this model.

Violent wave elastic structure Interaction

The aim of the research is to improve the understanding of fully nonlinear interaction between violent waves and elastic structures and to provide knowledge that can help to achieve a safe and cost-effective design of structures. For this, MLPG_R method is extended to study the interaction between the waves and the elastic structure. The elastic structure model is based on FEM. This research was funded by the Newton International fellowship (funded by The Royal Society, The Royal Academy of Engineers and British Academia) and the funding for follow-up activity every year would be 6000 GBP till 2021.

Results from WESI code

Users of this Code:

> Inhouse Testing phase

FNPT-NS solver

Violent Wave-Current Interaction with Offshore Wind energy Support Structure

A novel coupling concept has been introduced to model the experiments carried out at Large Wave tank (GWK tank, Hanover) by coupling the potential flow theory and Navier stokes equations (FNPT-NS solver). These two models are extensively developed over the past many years (see above IMLPG_R and SALEFEM). Further, a new set of experimental campaign will be carried out by towing the mono-pile under the action of waves generated by a wave-maker (free from spurious waves using second order corrected displacements), this would represent wave-current interaction with structure. This project is funded by the Alexander Von Humboldt Foundations.

Results from FNPT-NS solver

Users of this code:

1. Inhouse Testing phase.

IITM-WAVEGEN

This software was developed in order to generate the waves in the experimental wave tank. The software can generate signal to the wave paddle using first and second order wavemaker theory. Thus, making it possible to avoid any spurious wave generation. One can generate regular, Cnoidal, Solitary, N-waves, random waves, Focused waves and user defined waves (ex: field data). Further, one of the unique feature of this software is that one can simulataneosly run the FNPT-SALEFEM code (input from wavepaddle signal) and experimental waves. The test results shows the numerical code can reproduce the experiments with 95% accuracy for free surface elevation. The snapshot of the WAVEGEN is given below.

 

wavegen

Users of this tool:

1. Schneiderberg Flume (2m Flume), Franzius Institute, Germany.

2. Marienwerder (TWIN Flume), Franzius Institute, Germany.

3. 4m flume, IIT Madras

4. NIT Trichy.

 

FLUID-FLUID-ELASTIC SOLVER (IITM-2D FFES)

[Developed and Tested by Manoj Kumar, PhD]

The Fluid-Fluid-Elastic Structure (FFES) model is developed in the time domain to address the breaking wave impact on the structure.  The fluid-fluid model denotes that two different fluid models were used to describe fluid in the actual physical domain. The technique is a physics-based approximation to reduce the computational time, i.e. in the far-field inviscid fluid (fully nonlinear potential flow theory model), and near to the structure, viscous fluid (Navier Stokes model) is used. The coupled model then interacts with the elastic structure (based on Euler Bernoulli beam theory). The system of equations is strongly coupled both in space and time.

If the video is not playing click  https://www.youtube.com/watch?v=TWyoRs-ejec

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Shallow Water Equation Solver (IITM-FESWE)

[Developed and Tested by Shagun Agarwal, PhD]

This is an inhouse solver using 9 noded Lagrangian element based on FEM, leading to diagonal matrix. Thus, the simulation of the storm surge can be faster. The code is also ported with GPU. Coastal Inundation of typical Gaja Cyclone is shown below.
gaja1

 

 

Boussinesq Equation Solver (IITM-FEBOUSS)

[Developed and Tested by Shagun Agarwal, PhD]

This is an inhouse solver developed to address different aspects of the coastal engineering like tranquility, ship wakes, porous structures such as vegetation in large scale for practical purposes. The solver is based on FEM. Typical application of the solver is given below for chennai port as well as ship wakes.

3D Hybrid Boussinesq- NS solver (IITM-FEBOUSS-MLPG)

[Developed and Tested by Shagun Agarwal, PhD]

 This is the recent state of the art model, that couples the Boussinesq model with 3D NS solver based on FEM and MLPG (See details above).

3D RANSE solver (IITM-RANS3D)

[Developed and Tested by Dr.Shaswat Saincher, PostDoc]