RESEARCH BLOG

This page contains some of the research I have worked on over the years. The topics are computational in nature and vary from Lagrangian methods used in free-vortex methods and particle tracking, to full-fledged structured and unstructured computational fluid dynamics used to simular flow past rotorcrafts.

 

My primary research interests lie in,

  • Computational aerodynamics of flow past bodies

  • Mathematical and numerical modelling

  • Algorithms and their applications 

  • Overall design of aerospace vehicles

HAMSTR: A hybrid unstructured-structured methodology

A novel meshing and discretization paradigm for computational fluid dynamics that blends the relative ease of construction of unstructured grids with the accuracy, efficiency and robustness of structured grids. This technique is realized by exploiting the idea of Hamiltonian paths and strand grids.

 

Numerical Modelling of Rotorcraft Brownout

Brownout is a phenomenon that often occurs when rotorcraft operate over ground surfaces covered with mobile sediment material, such as loose soil, gravel or sand. Through a series of complex fluid dynamic uplift and sediment mobilizations mechanisms, the rotor wake stirs up a dust cloud that can quickly engulf the rotorcraft; which is both a safety of flight issue and one that results in high wear and tear of rotor blades and engine components.

 

The interactional aerodynamics around rotor(s), fuselage and the sediment is modelled in this work using a Lagrangian methodology and expedited using graphics processing units (GPUs).

HYDRA: Hybrid Design and Rotorcraft Analysis

HYDRA is a conceptual design toolkit co-developed with Ananth Sridharan that focuses on evaluating and analyzing unconventional (and conventional) configurations for a given mission profile. The toolkit is primarily written in Python and is integrated to other higher-fidelity methods such as a free-vortex wake and finite element analysis, which are written in a compiler based language. The goal is provide an insight into the aircraft performance and characteristics for a chosen configuration and mission.

 

HeliX: A High Speed Rotorcraft for Medevac Missions

HeliX was University of Maryland's response to the annual graduate design competition (this edition hosted by Eurocopter), which required a search and rescue vehicle capable of rescuing victims from a natural disaster. HeliX uses highly optimized proprotors and blades that enable it to travel at 317 knots. HeliX was adjudged the winner in the graduate category amongst international teams.

Particle Clustering Techniques for Modelling Dust Clouds

Particle clustering methods have been explored for application to the problem of predicting “brownout” conditions. A significant issue in such simulations is the tracking of the very large number of particles needed to predict with acceptable fidelity the dual-phase flow properties and optical characteristics of the dust clouds. It is shown that in some conditions they offer the potential to significantly reduce the computational costs of brownout dust cloud simulations while still retaining good accuracy. 

Algorithms and Some Applications

This section discusses some of the algorithms written and used towards practical applications in my work. One of the perennial issues with numerical codes, especially those geared towards a large amount of "number crunching" is that they require unfavourable amount of wall-clock time. Particularly, these algorithms have been used to group particles in a brownout cloud, find the wall distance used in turbulence modelling, or simulate the collision of particles with an airfoil.

 

Helicopter Design Competition (Faculty Advising)

During my stay at the University of Maryland, I had the privilege of working with talented students as part of the American Helicopter Society's international student design competition from 2016-2018. The three designs (all of which won the first place in their respective years) were the teams' response to an emergency vehicle that is deployed from a C-130J flying at 10,000 ft and 140 knots (2016 - Halcyon), 24 hour hovering machine (2017 - Elysium), and a reconfigurable high-speed urban vehicle (2018 - Metaltail).

 

Bharath Govindarajan

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