About Me

Profile Picture

Vision

My short-term vision is to contribute significantly to the understanding of fluid dynamics in complex enclosures, particularly through innovative computational and experimental approaches. In the long term, I aspire to lead pioneering research in fluid mechanics, leveraging cutting-edge technologies and interdisciplinary collaboration to address challenges in energy efficiency, sustainability, and engineering design.

Research Objective

My research focuses on the stability and bifurcation analysis of shear-driven flows, particularly Taylor-Couette flow in unconventional geometries. This includes exploring phenomena such as vortex formation, flow instabilities, and turbulent transitions in enclosures of varying shapes. By integrating advanced numerical methods like meshless solvers with experimental techniques, I aim to bridge theoretical predictions with real-world observations.

Career Objective

My career objective is to excel as a researcher and academician in fluid mechanics. I aim to contribute to the global scientific community by solving complex fluid dynamics problems and mentoring the next generation of engineers and scientists. I am particularly interested in advancing the development of high-performance computational tools and experimental techniques.

Research Philosophy

I believe that impactful research is driven by curiosity, collaboration, and innovation. By embracing multidisciplinary approaches and adopting open scientific practices, I strive to tackle intricate challenges with creativity and rigor. My work is fueled by a passion for unraveling the mysteries of fluid mechanics, and I am committed to translating theoretical advancements into practical applications that benefit society.




Publications

Presented at Conferences

  • Meshless - linear stability analysis for computations of flow instabilities in Couette flow within elliptical enclosure
    Authors: A. Unnikrishnan, V. Narayanan, & S. P. Vanka
    First European Fluid Dynamics Conference, EFDC1 (2024)
  • Bifurcations in Taylor-Couette flow within an elliptical enclosure
    Authors: A. Unnikrishnan, V. Narayanan, et al.
    ICTAM2024
  • Global stability analysis of eccentric Taylor Couette flow
    Authors: A. Unnikrishnan & V. Narayanan
    Division of Fluid Dynamics Meeting Abstracts (2021)

Published as Book Chapters

  • Signature of Linear Instability in Transition Zone Measurements in Boundary Layer
    Authors: A. Unnikrishnan & N. Vinod
    In: Suryan, A., et al. (eds) Lecture Notes in Mechanical Engineering. Springer (2020)

Submitted / Under Review

  • Rethinking Pipe Flow Stability: Insights from a Meshless Global Analysis
    Authors: A. Unnikrishnan, & V. Narayanan
    Under review at Physics of Fluids

In Preparation

  • Meshless multigrid methods for solution of Navier Stokes equations
    Authors: A. Unnikrishnan, V. Narayanan, & S. P. Vanka
    2024
  • Global Stability modes for pipe flow and transient energy growth mechanisms
    Authors: A. Unnikrishnan & V. Narayanan
    2024



Projects

Non-modal Stability Analysis of Dusty Channel Flows

A. Unnikrishnan, A. Kumar, V. Narayanan, R. Govindarajan [2024-present]

  • Developing a code to solve for non-modal stability of dusty channel flows with Chebyshev spectral discretisation.
  • Analysing the transient energy growth and identifying the worst initial condition.

GPU Accelerated Meshless Multigrid Incompressible Navier-Stokes Solver

A. Unnikrishnan, V. Narayanan, S. P. Vanka [2024-present]

  • Developing an OpenACC accelerated meshless multigrid solver for solving the Navier-Stokes equations using a semi-implicit algorithm.

PIV Visualization of Dominant Motions in Taylor-Couette Systems with Square Enclosures

A. Unnikrishnan, H. Jung, S. Cheng, V. Narayanan, S. P. Vanka, L. P. Chamorro [2023-present]

  • Under review in Journal of Fluid Mechanics..
  • Conducted PIV visualization experiments on Taylor-Couette flow in square enclosures.
  • Performed POD and SPOD analysis on experimental data; conducted linear stability analysis of the subcritical case.

High-Order Meshless Global Stability Analysis of Taylor-Couette Flows in Complex Domains

A. Unnikrishnan, V. Narayanan, S. P. Vanka [2021-2023]

  • Published in Physics of Fluids, 36(6), 2024..
  • Developed a novel meshless method for the computation of stability of fluid flows in complex domains.

Taylor-Couette Flow in an Elliptical Enclosure Generated by an Inner Rotating Circular Cylinder

A. Unnikrishnan, V. Narayanan, L. P. Chamorro, S. P. Vanka [2023]

  • Published in Physics of Fluids, 36(3), 033604..
  • Meshless method in two dimensions coupled with Fourier spectral methods for three-dimensional simulations.

Shear-Driven Flow in an Elliptical Enclosure Generated by an Inner Rotating Circular Cylinder

A. Unnikrishnan, S. Shahane, V. Narayanan, S. P. Vanka [2022]

  • Published in Physics of Fluids, 34(1), 013607.
  • Developed a meshless method to simulate Couette flow between an ellipse and a rotating circular cylinder.
  • Identified Moffatt-like vortices resulting from shear-driven flow in a slender elliptical enclosure.

Global Stability Analysis of Eccentric Taylor-Couette Flow

A. Unnikrishnan, V. Narayanan [2021]

  • Submitted to APS Division of Fluid Dynamics Meeting Abstracts (Q15-007)..
  • Part of SPARC (Scheme for Promotion of Academic and Research Collaboration) project.
  • Developed a Chebyshev-Fourier spectral method for biglobal stability analysis of eccentric Taylor-Couette flow using bipolar coordinates.

Spherical Microphone Array to Identify and Isolate Instrumental Sounds in a Room

A. Unnikrishnan, N. V. George [2021]

  • Independent project to design and develop a spherical microphone array.
  • Used Autodesk Inventor for modelling and 3D printing for rapid prototyping.

Search for Chaotic Motion in Eccentric Taylor-Couette Flows with an Inner Periodically Oscillating Cylinder

A. Unnikrishnan, V. Narayanan [2020]

  • Independent project to study the recirculation region dynamics within a Taylor-Couette flow between eccentrically placed circular cylinders with periodically oscillating inner cylinder.

Global Stability Analysis of a Horizontal Taylor-Couette Setup, with Radial Temperature Gradient

A. Unnikrishnan, U. Ghosh [2019]

  • Independent project to develop a global stability code using Chebyshev-Fourier spectral method.

Signature of Linear Instability in Transition Zone Measurements in Flat-plate Boundary Layers

A. Unnikrishnan, V. Narayanan [2018]

  • Performed simulations and experiments to detect oscillations/acoustic pressure fluctuations in boundary layer flow over a flat plate with a favourable and an adverse pressure gradient.
  • Solved the Orr-Sommerfeld equation to obtain perturbation Eigen modes.
  • Conducted experimental validation in a wind tunnel using acoustic pressure sensors.

Effect of Fin Geometry on Heat Transfer in a Single Cylinder Automobile Engine

A. Unnikrishnan, P. Arjunan [2016]

  • Used ANSYS Fluent to model and analyse flow over multiple fin designs for a single-cylinder automobile engine.
  • Proposed a new fin design, showing improved heat transfer efficiency based on simulation studies.

Stress Distribution on Coatings Over a Dental Implant

Fettle Engineering Pvt. Ltd. [2015]

  • Internship providing first exposure to a commercial environment, modelling, and simulation software.
  • Collaborated with medical students to model dental implants using provided catalogues.
  • Demonstrated that a specific coating improved durability over previous models through simulation studies.



Technical Skills

Computational Fluid Dynamics (CFD)

  • Expertise in solving fluid dynamics problems using Navier-Stokes solvers, conducting global stability analyses, and employing high-order numerical techniques.
  • Experience with meshless methods, spectral methods, finite volume methods, and finite difference methods.

Experimental Techniques

  • Skilled in Particle Image Velocimetry (PIV).
  • Experience with CTA anemometers for flow measurement, surface microphones, and pressure sensors.

Programming Languages

  • Proficient in FORTRAN, C, C++, MATLAB, Python for computational modeling, numerical simulations, and data analysis.

Software Tools

  • Experience with CFD simulation tools such as ANSYS Fluent, OpenFOAM, and Tecplot for simulations and post-processing.
  • Proficient in modeling tools like ProE, Creo, CATIA, SolidWorks, AutoCAD, and Inventor.
  • Competent with Microsoft Office and multimedia tools.
  • Familiar with web development using HTML5, Tailwind CSS, and Bootstrap.

Practical Training

  • Hands-on training during internships at Integral Coach Factory (Chennai), National Petroleum Construction Company (Abu Dhabi), and Quality Technical Services (Abu Dhabi).
  • Gained insights into industrial manufacturing and engineering practices.



References

Prof. Vinod Narayanan

Indian Institute of Technology Gandhinagar, Gujarat, India

vinod@iitgn.ac.in

Prof. Surya Pratap Vanka

University of Illinois at Urbana Champaign, Illinois, USA

spvanka@illinois.edu

Prof. Leonardo Chamorro

University of Illinois at Urbana Champaign, Illinois, USA

lpchamo@illinois.edu



Contact